{
    "children": [
        {
            "children": [
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "cc-early-math-counting", 
                                    "title": "Counting"
                                }, 
                                {
                                    "description": "", 
                                    "id": "cc-early-math-count-object-topic", 
                                    "title": "Counting objects"
                                }, 
                                {
                                    "description": "", 
                                    "id": "cc-early-math-comparing-numbers", 
                                    "title": "Comparing numbers through 10"
                                }
                            ], 
                            "description": "", 
                            "id": "cc-early-math-counting-topic", 
                            "title": "Counting"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "cc-early-math-tens", 
                                    "title": "Tens"
                                }, 
                                {
                                    "description": "", 
                                    "id": "cc-early-math-hundreds", 
                                    "title": "Hundreds"
                                }, 
                                {
                                    "description": "", 
                                    "id": "cc-early-math-skip-counting", 
                                    "title": "Skip-counting"
                                }, 
                                {
                                    "description": "", 
                                    "id": "cc-early-math-patterns-topic", 
                                    "title": "Patterns"
                                }
                            ], 
                            "description": "", 
                            "id": "cc-early-math-place-value-topic", 
                            "title": "Place value and patterns"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "basic-addition-subtraction", 
                                    "title": "Basic addition and subtraction"
                                }, 
                                {
                                    "description": "", 
                                    "id": "cc-early-math-add-subtract-10", 
                                    "title": "Addition and subtraction within 10"
                                }, 
                                {
                                    "description": "", 
                                    "id": "cc-early-math-add-subtract-20", 
                                    "title": "Addition and subtraction within 20"
                                }, 
                                {
                                    "description": "", 
                                    "id": "cc-early-math-add-subtract-100", 
                                    "title": "Addition and subtraction within 100"
                                }, 
                                {
                                    "description": "", 
                                    "id": "cc-early-math-add-subtract-1000", 
                                    "title": "Addition and subtraction within 1000"
                                }
                            ], 
                            "description": "", 
                            "id": "cc-early-math-add-sub-topic", 
                            "title": "Addition and subtraction"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "cc-early-math-measurement", 
                                    "title": "Measurement"
                                }, 
                                {
                                    "description": "", 
                                    "id": "cc-early-math-data", 
                                    "title": "Data"
                                }, 
                                {
                                    "description": "", 
                                    "id": "cc-early-math-time-money-topic", 
                                    "title": "Time and money"
                                }
                            ], 
                            "description": "", 
                            "id": "cc-early-math-measure-data-topic", 
                            "title": "Measurement and data"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "cc-early-math-recognizing-shapes", 
                                    "title": "Recognizing shapes"
                                }, 
                                {
                                    "description": "", 
                                    "id": "cc-early-math-composing-shapes", 
                                    "title": "Composing shapes"
                                }
                            ], 
                            "description": "", 
                            "id": "cc-early-math-geometry-topic", 
                            "title": "Geometry"
                        }
                    ], 
                    "description": " ", 
                    "id": "early-math", 
                    "title": "Early math"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "Adding and subtracting is the basis of all mathematics.  This tutorial introduces you to one-digit addition and subtraction.  You might become pretty familiar with the number line too!", 
                                    "id": "basic_addition", 
                                    "title": "Intro to addition and subtraction"
                                }, 
                                {
                                    "description": "In this tutorial, we'll start adding and subtracting numbers that have two (yes, two!) digits.  We won't be doing any carrying or borrowing (you'll learn what those are shortly) so you can see that adding or subtracting two digit numbers is really just an extension of what you already know.", 
                                    "id": "two_dig_add_sub", 
                                    "title": "Two digit addition and subtraction"
                                }, 
                                {
                                    "description": "You're somewhat familar with adding, say, 17+12 or 21+32, but what happens for 13+19?  Essentially, what happens when I max out the \"ones place\".  In this tutorial, we'll introduce you to the powerful tool of carrying and why it works.", 
                                    "id": "addition_carrying", 
                                    "title": "Addition with carrying"
                                }, 
                                {
                                    "description": "You can subtract 21 from 45, but are a bit perplexed trying to subtract 26 from 45 (how do you subtract the 6 in 26 from the 5 in 45).  This tutorial is your answer.  You'll see that we can essentially \"regroup\" the value in a number from one place to another to solve your problem.  This is also often called borrowing (although it is like \"borrowing\" sugar from your neighbor in that you never give it back).", 
                                    "id": "sub_borrowing", 
                                    "title": "Subtraction with borrowing (regrouping)"
                                }
                            ], 
                            "description": "Adding and subtracting positive and negative whole numbers. Starts with 1+1=2 and covers carrying, borrowing, and word problems.", 
                            "id": "addition-subtraction", 
                            "title": "Addition and subtraction"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Let's introduce ourselves to two of the most fundamental ideas in all of mathematics:  multiplication and division!", 
                                    "id": "mult-div-concept", 
                                    "title": "Concept of multiplication and division"
                                }, 
                                {
                                    "description": "If 3 kids each have two robot possums, how many total robot possums do we have?\n\nYou liked addition, but now you're ready to go to the next level.  Depending on how you view it, multiplication is about repeated addition or scaling a number or seeing what number you get when you have another number multiple times.  If that last sentence made little sense, you might enjoy this tutorial.", 
                                    "id": "multiplication_fun", 
                                    "title": "Basic multiplication"
                                }, 
                                {
                                    "description": "Every time you split your avocado harvest with your 10 pet robot possums, you've been dividing.  You don't farm avocados?  You only have 8 robot possums?  No worries.  I'm sure you've divided as well.\n\nMultiplication is awesome, but you're ready for the next step. Division is the art of trying to split things into equal groups.  Like subtraction undoes addition, division also undoes multiplication.  After this tutorial, you'll have a basic understanding of all of the core operations in arithmetic!", 
                                    "id": "delightful_division", 
                                    "title": "One-digit division"
                                }, 
                                {
                                    "description": "Math is super useful in the real world.  In this tutorial, we'll get some practice figuring out things that would have been tough without the powerful tools of multiplication and division!", 
                                    "id": "mult-div-word-problems", 
                                    "title": "Starter multiplication and division word problems"
                                }, 
                                {
                                    "description": "You know your multiplication tables and are ready to learn how to multiply *any* number (actually, any whole number).  Imagine the possibilities!  This tutorial will make you unstoppable.", 
                                    "id": "multi_digit_multiplication", 
                                    "title": "Multi-digit multiplication"
                                }, 
                                {
                                    "description": "You know your multiplication tables and are getting the hang of basic division.  In this tutorial, we will journey into the world of loooong division (sometimes, referred to as \"long division\", but that's not as much fun to say).\n\nAfter this tutorial, you'll be able to divide any whole number by any other.  The fun will not stop!", 
                                    "id": "long_division", 
                                    "title": "Loooong division!"
                                }, 
                                {
                                    "description": "Tired of \"standard multiplication\".  In this tutorial we'll explore a different way.  Not only is lattice multiplication interesting, it'll help us appreciate that there are many ways to do things.  We'll also try to grasp why it works in the first place.  Enjoy!", 
                                    "id": "lattice_multiplication", 
                                    "title": "Lattice multiplication"
                                }, 
                                {
                                    "description": "Feeling constrained by traditional long division?  Want to impress your friends, family and even your enemies?  Well, partial quotient division may be for you (or it might not).  This very optional tutorial will show you that there are many ways to slice a walnut (just made up that colloquialism).", 
                                    "id": "partial_quotient_division", 
                                    "title": "Partial quotient division"
                                }, 
                                {
                                    "description": "In this tutorial, we'll start to challenge you with more sophisticated multiplication and division word problems.\n\nIf you understand mult-digit multiplication and long division, you have all the tools you need to tackle these.\n\nMay the force be with you!", 
                                    "id": "advanced-mult-div-word-problems", 
                                    "title": "Fancy multiplication and division word problems"
                                }, 
                                {
                                    "description": "Most of us learn to multiply eventually, but only a select-few actually understand what the multiplication represents.  This tutorial, with the help of area models, will allow you to be part of this elite group. ", 
                                    "id": "area-models-multiplication", 
                                    "title": "Area models and multiplication"
                                }
                            ], 
                            "description": "Multiplying and dividing positive and negative whole numbers, understanding place value, and rounding numbers.", 
                            "id": "multiplication-division", 
                            "title": "Multiplication and division"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "What is a \"negative number\"?  What happens when I add or subtract one of these?\n\nIf you come to this tutorial armed with the basics of adding and subtracting numbers, you'll learn about what happens in the world below zero!  You will learn what negative numbers are and how we can add and subtract them.\n\n", 
                                    "id": "add-sub-negatives", 
                                    "title": "Negative number basics"
                                }, 
                                {
                                    "description": "You understand that negative numbers represent how far we are \"below zero\".  Now you are ready to add and subtract them!  In this tutorial, we will explain, give examples, and give practice adding and subtracting negative numbers.  \n\nThis is a super-important concept for the rest of your mathematical career so, no pressure, learn it as well as you can!", 
                                    "id": "adding_subtracting_negatives", 
                                    "title": "Adding and subtracting negative numbers"
                                }, 
                                {
                                    "description": "It is starting to dawn on you that negative numbers are incredibly awesome.  So awesome that you are feeling embarrassed to think how excited you are about them!\n\nWell, the journey is just beginning.  In this tutorial we will think about multiplying and dividing numbers throughout the number line!", 
                                    "id": "mult_div_negatives", 
                                    "title": "Multiplying and dividing negative numbers"
                                }, 
                                {
                                    "description": "You'll find absolute value absolutely straightforward--it is just the \"distance from zero.\"  If you have a positive number, it is its own absolute value.  If you have a negative number, just make it positive to get the absolute value.  \n\nAs you'll see as you develop mathematically, this idea will eventually extend to more contexts and dimensions, so it's super important that you understand this core concept now.", 
                                    "id": "abs_value_tutorial", 
                                    "title": "Absolute value"
                                }
                            ], 
                            "description": "Extending our understanding of numbers below 0.  Thinking about \"absolute\" distance from 0.", 
                            "id": "absolute-value", 
                            "title": "Negative numbers and absolute value"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "You've been using decimals all of your life.  When you pay $0.75 at a vending machine, 0.75 is a decimal.  When you see the ratings of gymnastics judges at the Olympics (\"9.5, 9.4, 7.5 (booooo)\"), those are decimals.  This tutorial will help you understand this powerful tool all the better.  Before you know it, you'll be representing numbers that are in-between whole numbers all the time!", 
                                    "id": "decimal_place_value", 
                                    "title": "Conceptualizing decimals and place notation"
                                }, 
                                {
                                    "description": "Let's explore how we can regroup and redistribute value among the various place values in a decimal number.", 
                                    "id": "regrouping-decimals", 
                                    "title": "Regrouping decimals"
                                }, 
                                {
                                    "description": "Let's think about where decimals are on a number line.  It will help us understand what decimals represent in general!", 
                                    "id": "decimals-on-number-line", 
                                    "title": "Decimals on a number line"
                                }, 
                                {
                                    "description": "Let's test our understanding of decimals by comparing them to one another!", 
                                    "id": "comparing-decimals", 
                                    "title": "Comparing decimals"
                                }, 
                                {
                                    "description": "You get the general idea of decimal is and what the digits in different places represent (place value).  Now you're ready to do something with the decimals.  Adding and subtracting is a good place to start.  This will allow you to add your family's expenses to figure out if your little brother is laundering money (perhaps literally).  Have fun!", 
                                    "id": "adding_decimals", 
                                    "title": "Adding and subtracting decimals"
                                }, 
                                {
                                    "description": "The real world is seldom about whole numbers.  If you precisely measure anything, you're likely to get a decimal.  If you don't know how to multiply these decimals, then you won't be able to do all the powerful things that multiplication can do in the real world (figure out your commission as a robot possum salesperson, determining how much shag carpet you need for your secret lair, etc.).", 
                                    "id": "multiplying_decimals", 
                                    "title": "Multiplying decimals"
                                }, 
                                {
                                    "description": "You can add, subtract and multiply decimals.  You know you'd feel a bit empty if you couldn't divide them as well. But something more powerful is going to happen.  If you are like us, you never quite liked those pesky remainders when dividing whole numbers.  Well, those pesky remainders better watch out because they are going to be divided too!!!! Ah ha ha ha ha!!!!!", 
                                    "id": "dividing_decimals", 
                                    "title": "Dividing decimals"
                                }, 
                                {
                                    "description": "Both fractions and decimals are desperate to capture that little part of our heart that desires to express non-whole numbers.  But must we commit?  Can't we have business in the front and party in the back (younger people should look up the word \"mullet\" to see a hair-style worth considering for your next trip to the barber)?  Can't it look like a pump, but feel like a sneaker?  Well, if 18-wheelers can turn into self-righteous robots, then why can't decimals and fractions turn into each other?", 
                                    "id": "decimal_to_fraction", 
                                    "title": "Converting between fractions and decimals"
                                }, 
                                {
                                    "description": "At least 50% of the math that you end up doing in your real life will involve percentages.  We're not really sure about that figure, but it sounds authoritative.  Anyway, unless you've watched this tutorial, you're really in no position to argue otherwise.\n\nAs you'll see \"percent\" literally means \"per cent\" or \"per hundred\".  It's a pseudo-decimally thing that our society likes to use even though decimals or fractions alone would have done the trick.  Either way, we're 100% sure you'll find this useful.", 
                                    "id": "percent_tutorial", 
                                    "title": "Intro to percentages"
                                }, 
                                {
                                    "description": "Whether you're calculating a tip at your favorite restaurant or figuring out how many decades you'll be paying your student debt because of the interest, percents will show up again and again and again in your life.  This tutorial will expose you to some of these problems before they show up in your actual life so you can handle them with ease (kind of like a vaccine for the brain).  Enjoy.", 
                                    "id": "percent_word_probs", 
                                    "title": "Percent word problems"
                                }, 
                                {
                                    "description": "Laziness is usually considered a bad thing.  But sometimes, it is useful to be lazy in a smart way.  Why do a big, hairy calculation if you just need a rough estimate? Why keep track of 2.345609 when you only need 2.35? \n\nThis tutorial will get you comfortable with sometimes being a little rough with numbers.  By being able to round and estimate them, it'll only add one more tool to your toolkit.", 
                                    "id": "decimal_rounding_estimation", 
                                    "title": "Estimating and rounding with decimals"
                                }, 
                                {
                                    "description": "There is a strong temptation in life to appear precise, even when you are aren't accurate.   If you  precisely measure one dimension of a carpet to be 3.256 meters and eyeball the other dimensional to be \"roughly 2 meters\", can you really claim that the area is  6.512 square meters (3.256 x 2)?  Isn't that a little misleading?  \n\nThis tutorial gets us thinking about this conundrum and gives us the best practices that scientists and engineers use to not mislead each other.", 
                                    "id": "significant_figures_tutorial", 
                                    "title": "Significant figures"
                                }, 
                                {
                                    "description": "In our decimal number system, as we move places to the left, the place values increase by a factor of 10 (likewise, they decrease by a factor of 10 as we move rightward).  This idea gets direct application when we multiply or divide a decimal number by 10 because it has the effect of shifting every place value one to the right or left (sometime seen as moving the decimal point).", 
                                    "id": "multiplying-dividing-by-10-decim", 
                                    "title": "Moving the decimal to multiply and divide by 10"
                                }, 
                                {
                                    "description": "If you think you know how to convert between decimals, fractions and percentages and are familiar with negative numbers, this tutorial is a good place to test all of those skills at the same time.", 
                                    "id": "decimals-percentages-fractions", 
                                    "title": "Adding and subtracting decimals, percentages, and fractions"
                                }
                            ], 
                            "description": "Understanding decimals conceptually, using operations with decimals, rounding and estimating with decimals, and converting decimals.", 
                            "id": "decimals", 
                            "title": "Decimals"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "If you don't understand fractions, you won't be even 1/3 educated.  Glasses will seem half empty rather than half full.  You'll be lucky to not be duped into some type of shady real-estate scheme or putting far too many eggs in your cake batter.\n\nGood thing this tutorial is here.  You'll see that fractions allow us to view the world in entirely new ways.  You'll see that everything doesn't have to be a whole.  You'll be able to slice and dice and then put it all back together (and if you order now, we'll throw in a spatula warmer for no extra charge).", 
                                    "id": "understanding_fractions", 
                                    "title": "Understanding fractions"
                                }, 
                                {
                                    "description": "Do you want 2/3 or 4/6 of this pizza?  Doesn't matter because they are both the same fraction.  This tutorial will help us explore this idea by really visualizing what equivalent fractions represent.", 
                                    "id": "visualizing-equivalent-fractions", 
                                    "title": "Visualizing equivalent fractions"
                                }, 
                                {
                                    "description": "There are literally infinite ways to represent any fraction (or number for that matter).  Don't believe us?  Let's take 1/3.  2/6, 3/9, 4/12 ... 10001/30003 are all equivalent fractions (and we could keep going)!  \n\nIf you know the basics of what a fraction is, this is a great tutorial for recognizing when fractions are equivalent and then simplifying them as much as possible!", 
                                    "id": "Equivalent_fractions", 
                                    "title": "Equivalent fractions and simplified form"
                                }, 
                                {
                                    "description": "In this tutorial, we'll practice understanding what quantities fractions actually represent and comparing those to each other.", 
                                    "id": "comparing-fractions", 
                                    "title": "Comparing fractions"
                                }, 
                                {
                                    "description": "In this tutorial, we'll see that a fraction can be broken up (or decomposed) into a bunch of other fractions.  You might see the world in a completely different way after this.", 
                                    "id": "decomposing-fractions", 
                                    "title": "Decomposing fractions"
                                }, 
                                {
                                    "description": "You've already got 2 cups of sugar in the cupboard.  Your grandmother's recipe for disgustingly-sweet-fudge-cake calls for 3 and 1/3 cups of sugar.  How much sugar do you need to borrow from you robot neighbor?\n\nAdding and subtracting fractions is key.  It might be a good idea to look at the equivalent fractions tutorial before tackling this one.", 
                                    "id": "Adding_and_subtracting_fractions", 
                                    "title": "Adding and subtracting fractions"
                                }, 
                                {
                                    "description": "We've already had some good practice adding fractions with like denominators.  We'll now add fractions with unlike denominators. This is a very big deal.  After this tutorial, you'll be able to add, pretty much, any two (or three or four or... ) fractions!", 
                                    "id": "fractions-unlike-denom", 
                                    "title": "Adding and subtracting fractions with unlike denominators"
                                }, 
                                {
                                    "description": "You know what a fraction is and are now eager to apply this knowledge to real-world situations (especially ones where the denominators aren't equal)?  Well, you're about to see that adding and subtracting fractions is far more powerful (and fun) then you've ever dreamed possible!", 
                                    "id": "adding-subtracting-fractions-wp", 
                                    "title": "Adding and subtracting with unlike denominator word problems"
                                }, 
                                {
                                    "description": "What is 2/3 of 2/3? If 4/7 of the class are boys, how many boys are there?\n\nMultiplying fractions is not only super-useful, but super-fun as well.", 
                                    "id": "multiplying_fractions", 
                                    "title": "Multiplying fractions"
                                }, 
                                {
                                    "description": "Multiplying fractions is useful. Period. That's all we really have to say.  Believe us don't believe us.  You'll learn eventually.  \n\nThis tutorial will have you multiplying in real-world scenarios (which is almost as fun as completely artificial, fake scenarios).", 
                                    "id": "multiplying-fractions-word-probl", 
                                    "title": "Multiplying fractions word problems"
                                }, 
                                {
                                    "description": "We can often have fractions whose numerators are not less than the denominators (like 23/4  or 3/2 or even 6/6).  These top-heavy friends are called improper fractions.  Since they represent a whole or more (in absolute terms), they can also be expressed as a combination of a whole number and a \"proper fraction\" (one where the numerator is less than the denominator) which is called a \"mixed number.\"  They are both awesome ways of representing a number and getting acquainted with both (as this tutorial does) is super useful in life!", 
                                    "id": "mixed_numbers", 
                                    "title": "Mixed numbers and improper fractions"
                                }, 
                                {
                                    "description": "You know the basics of what mixed numbers are.  You're now ready to add and subtract them.  This tutorial gives you plenty of examples and practice in this core skill!", 
                                    "id": "Mixed_number_add_sub", 
                                    "title": "Mixed number addition and subtraction"
                                }, 
                                {
                                    "description": "My recipe calls for a cup and a half of blueberries and serves 10 people.  But I have 23 people coming over.  How many cups of blueberries do I need?\n\nYou know that mixed numbers and improper fractions are two sides of the same coin (and you can convert between the two).  In this tutorial we'll learn to multiply and divide mixed numbers (mainly by converting them into improper fractions first).", 
                                    "id": "mixed_number_mult_div", 
                                    "title": "Mixed number multiplication and division"
                                }, 
                                {
                                    "description": "If you already know a bit about both decimals and fractions, this tutorial will help build a bridge between the two.  Through a bunch of examples and practice, you'll be able operate in both worlds.  Have fun!", 
                                    "id": "decimals_fractions", 
                                    "title": "Decimals and fractions"
                                }, 
                                {
                                    "description": "This is one exciting tutorial.  In it, we will understand that fractions can represent division (and the other way around).  Then we will create fractions by dividing whole numbers and then start dividing the fractions themselves.  We'll see that dividing by something is the exact same thing as multiplying by that thing's reciprocal!", 
                                    "id": "dividing-fractions-tutorial", 
                                    "title": "Dividing fractions"
                                }, 
                                {
                                    "description": "In this tutorial, we'll become fraction dividing experts!  In particular, we'll understand what it means to divide a fraction by another fraction.  Too much fun!!!", 
                                    "id": "div-fractions-fractions", 
                                    "title": "Dividing fractions by fractions"
                                }, 
                                {
                                    "description": "The world of numbers can be split up into multiple \"sets\", many of which overlap with each other (integers, rational numbers, irrational numbers, etc.).  This tutorial works through examples that expose you to the terminology of the various sets and how you can differentiate them.", 
                                    "id": "number_sets", 
                                    "title": "Number sets"
                                }
                            ], 
                            "description": "Understanding fractions conceptually, using operations with fractions, and converting fractions.", 
                            "id": "fractions", 
                            "title": "Fractions"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Learn to tell time with some fun exercises!", 
                                    "id": "telling-time", 
                                    "title": "Telling time"
                                }
                            ], 
                            "description": "", 
                            "id": "telling-time-topic", 
                            "title": "Telling time"
                        }
                    ], 
                    "description": "The first math topic. Start here if you want to learn the basics (or just want to make sure you know these topics).", 
                    "id": "arithmetic", 
                    "title": "Arithmetic"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "What is a \"negative number\"?  What happens when I add or subtract one of these?\n\nIf you come to this tutorial armed with the basics of adding and subtracting numbers, you'll learn about what happens in the world below zero!  You will learn what negative numbers are and how we can add and subtract them.\n\n", 
                                    "id": "add-sub-negatives-pre-alg", 
                                    "title": "Negative number basics"
                                }, 
                                {
                                    "description": "You understand that negative numbers represent how far we are \"below zero\".  Now you are ready to add and subtract them!  In this tutorial, we will explain, give examples, and give practice adding and subtracting negative numbers.  \n\nThis is a super-important concept for the rest of your mathematical career so, no pressure, learn it as well as you can!", 
                                    "id": "add-subtract-negatives-pre-alg", 
                                    "title": "Adding and subtracting negative numbers"
                                }, 
                                {
                                    "description": "It is starting to dawn on you that negative numbers are incredibly awesome.  So awesome that you are feeling embarrassed to think how excited you are about them!\n\nWell, the journey is just beginning.  In this tutorial we will think about multiplying and dividing numbers throughout the number line!", 
                                    "id": "mult-div-negatives-pre-alg", 
                                    "title": "Multiplying and dividing negative numbers"
                                }, 
                                {
                                    "description": "You'll find absolute value absolutely straightforward--it is just the \"distance from zero.\"  If you have a positive number, it is its own absolute value.  If you have a negative number, just make it positive to get the absolute value.  \n\nAs you'll see as you develop mathematically, this idea will eventually extend to more contexts and dimensions, so it's super important that you understand this core concept now.", 
                                    "id": "abs-value-pre-alg", 
                                    "title": "Absolute value"
                                }
                            ], 
                            "description": "", 
                            "id": "negatives-absolute-value-pre-alg", 
                            "title": "Negative numbers and absolute value"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Whether you are trying to impress your dog's friends (who are obsessed with figuring out number divisibility) or quickly factor a number, it can be very useful to tell whether a number is divisible by another.  This tutorial walks through some of the more standard divisibility methods and describes why they work.", 
                                    "id": "divisibility_tests", 
                                    "title": "Divisibility tests"
                                }, 
                                {
                                    "description": "In this tutorial, we'll begin to think about the numbers that \"make up\" the number.  This will be useful throughout our study of math.  Whether we are adding fractions, exploring mystical number patterns, or breaking computer codes, factoring numbers are key!  Eye of the tiger!", 
                                    "id": "divisibility_and_factors", 
                                    "title": "Divisibility and factors"
                                }, 
                                {
                                    "description": "Prime numbers have been studied by mathematicians and mystics for ages (seriously).  They are both basic and mysterious.  The more you explore them, the more you will realize that the universe is a fascinating place.  This tutorial will introduce you to the magical world of prime numbers.", 
                                    "id": "prime_numbers", 
                                    "title": "Prime numbers"
                                }, 
                                {
                                    "description": "You know what prime numbers are and how to identify them.  In this tutorial, we'll see that *all* positive whole numbers can be broken down into products of prime numbers (In some way, prime numbers are the \"atoms\" of the number world that can be multiplied to create any other number).  Besides being a fascinating idea, it is also extremely useful.  Prime factorization can be used to decrypt encrypted information!", 
                                    "id": "prime_factorization", 
                                    "title": "Prime factorization"
                                }, 
                                {
                                    "description": "Life is good, but it can always get better.  Just imagine being able to find the smallest number that is a multiple of two other numbers!  Other than making your life more fulfilling, it will allow you to do incredible things like adding fractions.", 
                                    "id": "least_common_multiple", 
                                    "title": "Least common multiple"
                                }, 
                                {
                                    "description": "You know how to find factors of a number.  But what about factors that are common to two numbers?  Even better, imagine the largest factors that are common to two numbers.   I know.  Too exciting!", 
                                    "id": "greatest_common_divisor", 
                                    "title": "Greatest common divisor"
                                }
                            ], 
                            "description": "Understanding and finding factors and multiples. After these videos, you'll be ready for fractions.", 
                            "id": "factors-multiples", 
                            "title": "Factors and multiples"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "You've been using decimals all of your life.  When you pay $0.75 at a vending machine, 0.75 is a decimal.  When you see the ratings of gymnastics judges at the Olympics (\"9.5, 9.4, 7.5 (booooo)\"), those are decimals.  This tutorial will help you understand this powerful tool all the better.  Before you know it, you'll be representing numbers that are in-between whole numbers all the time!", 
                                    "id": "decimal-place-value-pre-alg", 
                                    "title": "Conceptualizing decimals and place notation"
                                }, 
                                {
                                    "description": "Let's explore how we can regroup and redistribute value among the various place values in a decimal number.", 
                                    "id": "regrouping-decimals-pre-alg", 
                                    "title": "Regrouping decimals"
                                }, 
                                {
                                    "description": "Let's think about where decimals are on a number line.  It will help us understand what decimals represent in general!", 
                                    "id": "decimals-on-number-line-pre-alg", 
                                    "title": "Decimals on a number line"
                                }, 
                                {
                                    "description": "Let's test our understanding of decimals by comparing them to one another!", 
                                    "id": "comparing-decimals-pre-alg", 
                                    "title": "Comparing decimals"
                                }, 
                                {
                                    "description": "You get the general idea of decimal is and what the digits in different places represent (place value).  Now you're ready to do something with the decimals.  Adding and subtracting is a good place to start.  This will allow you to add your family's expenses to figure out if your little brother is laundering money (perhaps literally).  Have fun!", 
                                    "id": "adding-decimals-pre-alg", 
                                    "title": "Adding and subtracting decimals"
                                }, 
                                {
                                    "description": "The real world is seldom about whole numbers.  If you precisely measure anything, you're likely to get a decimal.  If you don't know how to multiply these decimals, then you won't be able to do all the powerful things that multiplication can do in the real world (figure out your commission as a robot possum salesperson, determining how much shag carpet you need for your secret lair, etc.).", 
                                    "id": "multiplying-decimals-pre-alg", 
                                    "title": "Multiplying decimals"
                                }, 
                                {
                                    "description": "You can add, subtract and multiply decimals.  You know you'd feel a bit empty if you couldn't divide them as well. But something more powerful is going to happen.  If you are like us, you never quite liked those pesky remainders when dividing whole numbers.  Well, those pesky remainders better watch out because they are going to be divided too!!!! Ah ha ha ha ha!!!!!", 
                                    "id": "dividing-decimals-pre-alg", 
                                    "title": "Dividing decimals"
                                }, 
                                {
                                    "description": "Both fractions and decimals are desperate to capture that little part of our heart that desires to express non-whole numbers.  But must we commit?  Can't we have business in the front and party in the back (younger people should look up the word \"mullet\" to see a hair-style worth considering for your next trip to the barber)?  Can't it look like a pump, but feel like a sneaker?  Well, if 18-wheelers can turn into self-righteous robots, then why can't decimals and fractions turn into each other?", 
                                    "id": "decimal-to-fraction-pre-alg", 
                                    "title": "Converting between fractions and decimals"
                                }, 
                                {
                                    "description": "", 
                                    "id": "percent-intro-pre-alg", 
                                    "title": "Intro to percentages"
                                }, 
                                {
                                    "description": "Whether you're calculating a tip at your favorite restaurant or figuring out how many decades you'll be paying your student debt because of the interest, percents will show up again and again and again in your life.  This tutorial will expose you to some of these problems before they show up in your actual life so you can handle them with ease (kind of like a vaccine for the brain).  Enjoy.", 
                                    "id": "percent-word-probs-pre-alg", 
                                    "title": "Percent word problems"
                                }, 
                                {
                                    "description": "Laziness is usually considered a bad thing.  But sometimes, it is useful to be lazy in a smart way.  Why do a big, hairy calculation if you just need a rough estimate? Why keep track of 2.345609 when you only need 2.35? \n\nThis tutorial will get you comfortable with sometimes being a little rough with numbers.  By being able to round and estimate them, it'll only add one more tool to your toolkit.", 
                                    "id": "dec-rounding-estimation-pre-alg", 
                                    "title": "Estimating and rounding with decimals"
                                }, 
                                {
                                    "description": "There is a strong temptation in life to appear precise, even when you are aren't accurate.   If you  precisely measure one dimension of a carpet to be 3.256 meters and eyeball the other dimensional to be \"roughly 2 meters\", can you really claim that the area is  6.512 square meters (3.256 x 2)?  Isn't that a little misleading?  \n\nThis tutorial gets us thinking about this conundrum and gives us the best practices that scientists and engineers use to not mislead each other.", 
                                    "id": "sig-figs-pre-alg", 
                                    "title": "Significant figures"
                                }, 
                                {
                                    "description": "In our decimal number system, as we move places to the left, the place values increase by a factor of 10 (likewise, they decrease by a factor of 10 as we move rightward).  This idea gets direct application when we multiply or divide a decimal number by 10 because it has the effect of shifting every place value one to the right or left (sometime seen as moving the decimal point).", 
                                    "id": "mult-div-by-10-dec-pre-alg", 
                                    "title": "Moving the decimal to multiply and divide by 10"
                                }, 
                                {
                                    "description": "If you think you know how to convert between decimals, fractions and percentages and are familiar with negative numbers, this tutorial is a good place to test all of those skills at the same time.", 
                                    "id": "dec-perc-frac-pre-alg", 
                                    "title": "Adding and subtracting decimals percentages and fractions"
                                }
                            ], 
                            "description": "", 
                            "id": "decimals-pre-alg", 
                            "title": "Decimals"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "If you don't understand fractions, you won't be even 1/3 educated.  Glasses will seem half empty rather than half full.  You'll be lucky to not be duped into some type of shady real-estate scheme or putting far too many eggs in your cake batter.\n\nGood thing this tutorial is here.  You'll see that fractions allow us to view the world in entirely new ways.  You'll see that everything doesn't have to be a whole.  You'll be able to slice and dice and then put it all back together (and if you order now, we'll throw in a spatula warmer for no extra charge).", 
                                    "id": "understanding-fractions-pre-alg", 
                                    "title": "Understanding fractions"
                                }, 
                                {
                                    "description": "Do you want 2/3 or 4/6 of this pizza?  Doesn't matter because they are both the same fraction.  This tutorial will help us explore this idea by really visualizing what equivalent fractions represent.", 
                                    "id": "visualizing-equiv-fracs-pre-alg", 
                                    "title": "Visualizing equivalent fractions"
                                }, 
                                {
                                    "description": "There are literally infinite ways to represent any fraction (or number for that matter).  Don't believe us?  Let's take 1/3.  2/6, 3/9, 4/12 ... 10001/30003 are all equivalent fractions (and we could keep going)!  \n\nIf you know the basics of what a fraction is, this is a great tutorial for recognizing when fractions are equivalent and then simplifying them as much as possible!", 
                                    "id": "equivalent-fractions-pre-alg", 
                                    "title": "Equivalent fractions and simplified form"
                                }, 
                                {
                                    "description": "In this tutorial, we'll practice understanding what quantities fractions actually represent and comparing those to each other.", 
                                    "id": "comparing-fractions-pre-alg", 
                                    "title": "Comparing fractions"
                                }, 
                                {
                                    "description": "In this tutorial, we'll see that a fraction can be broken up (or decomposed) into a bunch of other fractions.  You might see the world in a completely different way after this.", 
                                    "id": "decomposing-fractions-pre-alg", 
                                    "title": "Decomposing fractions"
                                }, 
                                {
                                    "description": "We've already had some good practice adding fractions with like denominators.  We'll now add fractions with unlike denominators. This is a very big deal.  After this tutorial, you'll be able to add, pretty much, any two (or three or four or... ) fractions!", 
                                    "id": "fractions-unlike-denom-pre-alg", 
                                    "title": "Adding and subtracting fractions with unlike denominators"
                                }, 
                                {
                                    "description": "You've already got 2 cups of sugar in the cupboard.  Your grandmother's recipe for disgustingly-sweet-fudge-cake calls for 3 and 1/3 cups of sugar.  How much sugar do you need to borrow from you robot neighbor?\n\nAdding and subtracting fractions is key.  It might be a good idea to look at the equivalent fractions tutorial before tackling this one.", 
                                    "id": "add-and-subtract-fracs-pre-alg", 
                                    "title": "Adding and subtracting fractions"
                                }, 
                                {
                                    "description": "You know what a fraction is and are now eager to apply this knowledge to real-world situations (especially ones where the denominators aren't equal)?  Well, you're about to see that adding and subtracting fractions is far more powerful (and fun) then you've ever dreamed possible!", 
                                    "id": "add-subtract-fracs-wp-pre-alg", 
                                    "title": "Adding and subtracting with unlike denominator word problems"
                                }, 
                                {
                                    "description": "What is 2/3 of 2/3? If 4/7 of the class are boys, how many boys are there?\n\nMultiplying fractions is not only super-useful, but super-fun as well.", 
                                    "id": "multiplying-fractions-pre-alg", 
                                    "title": "Multiplying fractions"
                                }, 
                                {
                                    "description": "Multiplying fractions is useful. Period. That's all we really have to say.  Believe us don't believe us.  You'll learn eventually.  \n\nThis tutorial will have you multiplying in real-world scenarios (which is almost as fun as completely artificial, fake scenarios).", 
                                    "id": "mult-fracs-word-probs-pre-alg", 
                                    "title": "Multiplying fractions word problems"
                                }, 
                                {
                                    "description": "We can often have fractions whose numerators are not less than the denominators (like 23/4  or 3/2 or even 6/6).  These top-heavy friends are called improper fractions.  Since they represent a whole or more (in absolute terms), they can also be expressed as a combination of a whole number and a \"proper fraction\" (one where the numerator is less than the denominator) which is called a \"mixed number.\"  They are both awesome ways of representing a number and getting acquainted with both (as this tutorial does) is super useful in life!", 
                                    "id": "mixed-numbers-pre-alg", 
                                    "title": "Mixed numbers and improper fractions"
                                }, 
                                {
                                    "description": "You know the basics of what mixed numbers are.  You're now ready to add and subtract them.  This tutorial gives you plenty of examples and practice in this core skill!", 
                                    "id": "mixed-number-add-sub-pre-alg", 
                                    "title": "Mixed number addition and subtraction"
                                }, 
                                {
                                    "description": "My recipe calls for a cup and a half of blueberries and serves 10 people.  But I have 23 people coming over.  How many cups of blueberries do I need?\n\nYou know that mixed numbers and improper fractions are two sides of the same coin (and you can convert between the two).  In this tutorial we'll learn to multiply and divide mixed numbers (mainly by converting them into improper fractions first).", 
                                    "id": "mixed-number-mult-div-pre-alg", 
                                    "title": "Mixed number multiplication and division"
                                }, 
                                {
                                    "description": "If you already know a bit about both decimals and fractions, this tutorial will help build a bridge between the two.  Through a bunch of examples and practice, you'll be able operate in both worlds.  Have fun!", 
                                    "id": "decimals-fractions-pre-alg", 
                                    "title": "Decimals and fractions"
                                }, 
                                {
                                    "description": "This is one exciting tutorial.  In it, we will understand that fractions can represent division (and the other way around).  Then we will create fractions by dividing whole numbers and then start dividing the fractions themselves.  We'll see that dividing by something is the exact same thing as multiplying by that thing's reciprocal!", 
                                    "id": "dividing-fractions-pre-alg", 
                                    "title": "Dividing fractions"
                                }, 
                                {
                                    "description": "In this tutorial, we'll become fraction dividing experts!  In particular, we'll understand what it means to divide a fraction by another fraction.  Too much fun!!!", 
                                    "id": "div-fractions-fractions-pre-alg", 
                                    "title": "Dividing fractions by fractions"
                                }
                            ], 
                            "description": "", 
                            "id": "fractions-pre-alg", 
                            "title": "Fractions"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Would you rather go to a college with a high teacher-to-student ratio or a low one?  What about the ratio of girls-to-boys?  What is the ratio of eggs to butter in your favorite dessert?\n\nRatios show up EVERYWHERE in life.  This tutorial introduces you to what they (and proportions) are and how to make good use of them!", 
                                    "id": "ratios_and_proportions", 
                                    "title": "Ratios and proportions"
                                }, 
                                {
                                    "description": "How fast can a robot possum fly?  What is the rate at which a hungry you can consume avocados?  \n\nThis tutorial helps you make sense of these fundamental questions in life.", 
                                    "id": "rates_tutorial", 
                                    "title": "Rates"
                                }, 
                                {
                                    "description": "Wait, I'm in Europe and my car only tells my distance traveled in kilometers!  But I'm used to a units of distance devised by the Romans to measure the average length of 1000 paces of a soldier (the \"mile\")!  How do I operate?  \n\nThis tutorial is about the fundamental skill of unit conversion.  Sal's cousin Nadia being a bit confused  with this was actually the reason why he started tutoring her (which led to the creation of the Khan Academy).", 
                                    "id": "unit_conversion", 
                                    "title": "Unit conversion"
                                }, 
                                {
                                    "description": "You might be surprised to realize that only two countries in the world use feet, miles, or yards or a bunch of other \"English System\" conventions  (the irony being that the English don't even use the \"English System\" any more).   Everyone else, including the English, now use the metric system which is actually much more logical.\n\nLearn about kilo and milli and centi and become a metric unit megastar!", 
                                    "id": "metric-system-tutorial", 
                                    "title": "Metric system unit conversion"
                                }, 
                                {
                                    "description": "There are three major conventions for measuring temperature in the world, Fahrenheit, Celsius and Kelvin.  If converting between the three gives you cold feet, then this tutorial might warm them up.", 
                                    "id": "farenheit-celsius-conversion", 
                                    "title": "Fahrenheit and Celsius conversion"
                                }
                            ], 
                            "description": "", 
                            "id": "rates-and-ratios", 
                            "title": "Ratios, proportions, units, and rates"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "This tutorial is less about statistics and more about interpreting data--whether it is presented as a table, pictograph, bar graph or line graph.  Good for someone new to these ideas.  For a student in high school or college looking to learn statistics, it might make sense to skip (although it might not hurt either).", 
                                    "id": "reading_data", 
                                    "title": "Reading and interpreting data"
                                }, 
                                {
                                    "description": "The world seldom gives you two numbers and tells you which operation to perform.  More likely, you'll be presented with a bunch of information and you (yes, YOU) need to make sense of them.  This tutorial gives you practice doing exactly that.  When watching videos, pause and attempt it before Sal.  Then work on as many problems as you want in the exercise at the end of the tutorial.", 
                                    "id": "multistep-word-problems-tut", 
                                    "title": "Multi-step word problems"
                                }, 
                                {
                                    "description": "Equality is usually a good thing, but the world is not a perfect place.  No matter how hard we try, we can't help but compare one thing to another and realize how unequal they may be.\n\nThis tutorial gives you the tools to do these comparisons in the mathematical world (which we call inequalities).  You'll become familiar with the \"greater than\" and \"less than symbols\" and learn to use them.", 
                                    "id": "greater-than-less-than", 
                                    "title": "Inequalities : Greater than and less than basics"
                                }, 
                                {
                                    "description": "You've probably been learning how to do arithmetic for some time and feel pretty good about it.  This tutorial will make you feel even better once by showing you a bunch of examples of where it can be applied (using multiple skills at a time).  Get through the exercises here and you really are an arithmetic rock star!", 
                                    "id": "cross-topic-arithmetic", 
                                    "title": "Cross topic arithmetic"
                                }, 
                                {
                                    "description": "Let's explore how numbers can grow in different ways and use what we learn to figure out where they can go.  We think you'll find this tutorial on number patterns more fun that you do :)\n\n", 
                                    "id": "number-patterns", 
                                    "title": "Number patterns"
                                }, 
                                {
                                    "description": "Let's construct and interpret expressions from word problems.  We can also think about what the effects of parentheses are.", 
                                    "id": "constructing-numeric-expressions", 
                                    "title": "Constructing numeric expressions"
                                }
                            ], 
                            "description": "You already have many tools in your mathematical toolkit.  In this topic, you'll use these in settings that you're likely to encounter in the real world!", 
                            "id": "applying-math-reasoning-topic", 
                            "title": "Applying mathematical reasoning"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Addition was nice.  Multiplication was cooler.  In the mood for a new operation that grows numbers even faster?  Ever felt like expressing repeated multiplication with less writing?  Ever wanted to describe how most things in the universe grow and shrink?  Well, exponents are your answer!\n\nThis tutorial covers everything from basic exponents to negative and fractional ones.  It assumes you remember your multiplication, negative numbers and fractions.", 
                                    "id": "world-of-exponents", 
                                    "title": "The world of exponents"
                                }, 
                                {
                                    "description": "A strong contender for coolest symbol in mathematics is the radical.  What is it?  How does it relate to exponents?  How is the square root different than the cube root?  How can I simplify, multiply and add these things?  \n\nThis tutorial assumes you know the basics of exponents and exponent properties and takes you through the radical world for radicals (and gives you some good practice along the way)!", 
                                    "id": "radical-radicals", 
                                    "title": "The square root"
                                }, 
                                {
                                    "description": "If you're familiar with the idea of a square root, we're about to take things one step (dimension?) further with the cube root.  This generally refers to finding a number that ,when cubed, is equal to the number that you're trying to find the cube root of!", 
                                    "id": "cube-root-tutorial", 
                                    "title": "The cube root"
                                }, 
                                {
                                    "description": "Tired of hairy exponent expressions?  Feel compelled to clean them up?  Well, this tutorial might just give you the tools you need.\n\nIf you know a bit about exponents, you'll learn a ton more in this tutorial as you learn about the rules for simplifying exponents.", 
                                    "id": "exponent-properties", 
                                    "title": "Exponent properties"
                                }, 
                                {
                                    "description": "It's normally a bad idea to hang around with negative people or do negative things, but we think it's OK to associate with negative exponents.  And fractional exponents are even more fun.\n\nThis idea will open up entirely new vistas to your mathematical life.  ", 
                                    "id": "negative-exponents-tutorial", 
                                    "title": "Negative and fractional exponents"
                                }, 
                                {
                                    "description": "Scientists and engineers often have to deal with super huge (like 6,000,000,000,000,000,000,000) and super small numbers (like 0.0000000000532) .  How can they do this without tiring their hands out?  How can they look at a number and understand how large or small it is without counting the digits?  The answer is to use scientific notation.\n\nIf you come to this tutorial with a basic understanding of positive and negative exponents, it should leave you with a new appreciation for representing really huge and really small numbers!", 
                                    "id": "scientific-notation", 
                                    "title": "Scientific notation"
                                }, 
                                {
                                    "description": "When people want to think about the general size of things but not worry about the exact number, they tend to think in terms of \"orders of magnitude\".  This allows us to analyze and make comparisons between numbers very quickly, which allows us to make decisions about them quickly as well.", 
                                    "id": "orders-of-magnitude", 
                                    "title": "Orders of magnitude"
                                }, 
                                {
                                    "description": "You already understand what scientific notation is.  Now you'll actually use it to compute values and solve real-world problems.", 
                                    "id": "computing-scientific-notation", 
                                    "title": "Computing with scientific notation"
                                }
                            ], 
                            "description": "Understanding and solving exponents without algebra.", 
                            "id": "exponents-radicals", 
                            "title": "Exponents, radicals, and scientific notation"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "You've been counting for a while now.  It's second nature to go from \"9\" to \"10\" or \"99\" to \"100\", but what are you really doing when you add another digit?  How do we represent so many numbers (really as many as we want) with only 10 number symbols (0, 1, 2, 3, 4, 5, 6, 7, 8, 9)?\n\nIn this tutorial you'll learn about place value.  This is key to better understanding what you're really doing when you count, carry, regroup, multiply and divide with mult-digit numbers.  If you really think about it, it might change your worldview forever!", 
                                    "id": "place_value", 
                                    "title": "Place value"
                                }, 
                                {
                                    "description": "If you're looking to create an army of robot dogs, will it really make a difference if you have 10,300 dogs, 9,997 dogs or 10,005 dogs?  Probably not.  All you really care about is how many dogs you have to, say, the nearest thousand (10,000 dogs).\n\nIn this tutorial, you'll learn about conventions for rounding whole numbers.  Very useful when you might not need to (or cannot) be completely precise.", 
                                    "id": "rounding_whole_numbers", 
                                    "title": "Rounding whole numbers"
                                }, 
                                {
                                    "description": "Whether with words or numbers, we'll try to understand multiple ways of representing a whole number quantity.  We'll even play with place value a good bit to make sure that everything is clicking!", 
                                    "id": "whole-number-representations-tut", 
                                    "title": "Understanding whole number representations"
                                }, 
                                {
                                    "description": "Regrouping involves taking value from one place and giving it to another.  It is a great way to make sure you understand place value.  It is also super useful when subtracting multi-digit numbers (the process is often called \"borrowing\" even though you never really \"pay back\" the value taken from one place and given to another).", 
                                    "id": "regrouping-whole-numbers", 
                                    "title": "Regrouping whole numbers"
                                }, 
                                {
                                    "description": "How many times do you need to cut a cake?  How many fence posts do you need?\n\nThese life altering decisions will be based on how well you count.  ", 
                                    "id": "counting tutorial", 
                                    "title": "Counting"
                                }, 
                                {
                                    "description": "More numbers than you probably imagine can be represented as the ratio of two integers.  We call these rational numbers. But there are also really amazing numbers that can't.  As you can guess, we call them irrational numbers.", 
                                    "id": "rational-irrational-numbers", 
                                    "title": "Rational and irrational numbers"
                                }, 
                                {
                                    "description": "If you have the expression \"3 + 4 x 5\", do you add the 3 to the 4 first or multiply the 4 and 5 first?  To clear up confusion here, the math world has defined which operation should get priority over others.  This is super important.  You won't really be able to do any involved math if you don't get this clear.  But don't worry, this tutorial has your back.", 
                                    "id": "order_of_operations", 
                                    "title": "Order of operations"
                                }, 
                                {
                                    "description": "The distributive property is an idea that shows up over and over again in mathematics.  It is the idea that 5 x (3 + 4) = (5 x 3) + (5 x 4).  If that last statement made complete sense, no need to watch this tutorial.  If it didn't or you don't know why it's true, then this tutorial might be a good way to pass the time :)", 
                                    "id": "ditributive_property", 
                                    "title": "The distributive property"
                                }, 
                                {
                                    "description": "2 + 3 = 3 + 2, 6 x 4 = 4 x 6.  Adding zero to a number does not change the number.  Likewise, multiplying a number by 1 does not change it.\n\nYou may already know these things from working through other tutorials, but some people (not us) like to give these properties names that sound far more complicated than the property themselves.  This tutorial (which we're not a fan of), is here just in case you're asked to identify the \"Commutative Law of Multiplication\".   We believe the important thing isn't the fancy label, but the underlying idea (which isn't that fancy).", 
                                    "id": "arithmetic_properties", 
                                    "title": "Arithmetic properties"
                                }
                            ], 
                            "description": "This tutorial will help us make sure we can go deep on arithmetic. We'll explore various ways to represent whole numbers, place value, order of operations, rounding and various other properties of arithmetic.", 
                            "id": "order-of-operations", 
                            "title": "Arithmetic properties"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Area is how we thinking about how much space something takes in two dimensions such as comparing how much land one property takes up versus another.  In this tutorial, we'll take a conceptual look at how area is actually measured (especially for rectangles).", 
                                    "id": "area-basics", 
                                    "title": "Area basics"
                                }, 
                                {
                                    "description": "Have you ever wondered how much fencing you need to surround a plot of land?  No?  Well, you should still go through this tutorial just in case.  You'll learn all about how to think about and calculate perimeter--essentially the length of the boundary of a figure.", 
                                    "id": "perimeter", 
                                    "title": "Perimeter"
                                }, 
                                {
                                    "description": "In this tutorial, you'll stretch your understanding of area and perimeter by applying it to word problems.", 
                                    "id": "rectangle-area-perimeter-word-pr", 
                                    "title": "Rectangle area and perimeter word problems"
                                }, 
                                {
                                    "description": "Volume measures how much 3-dimensional \"space\" an object takes up.  We'll see in this tutorial that it is an extension of length (1-D) or area (2-D) to three dimensions!", 
                                    "id": "volume-introduction-rectangular", 
                                    "title": "Volume of a box or rectangular prism"
                                }
                            ], 
                            "description": "From length to area to volume to time, thinking about how we measure things.", 
                            "id": "measurement", 
                            "title": "Measurement"
                        }
                    ], 
                    "description": "If you've mastered the basics of arithmetic and are ready to learn more about numbers and operations, you're in the right place!", 
                    "id": "pre-algebra", 
                    "title": "Pre-algebra"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "Did you realize that the word \"algebra\" comes from Arabic (just like \"algorithm\" and \"al jazeera\" and \"Aladdin\")?  And what is so great about algebra anyway?  \n\nThis tutorial doesn't explore algebra so much as it introduces the history and ideas that underpin it.", 
                                    "id": "overview_hist_alg", 
                                    "title": "Overview and history of algebra"
                                }, 
                                {
                                    "description": "Wait, why are we using letters in math?  How can an 'x' represent a number?  What number is it?  I must figure this out!!! Yes, you must.\n\nThis tutorial is great if you're just beginning to delve into the world of algebraic variables and expressions.", 
                                    "id": "variable-and-expressions", 
                                    "title": "Variables and expressions"
                                }, 
                                {
                                    "description": "Using the combined powers of Chuck Norris and polar bears (which are much less powerful than Mr. Norris) to better understand what expressions represent and how we can manipulate them.\n\nGreat tutorial if you want to understand that expressions are just a way to express things!", 
                                    "id": "manipulating-expressions", 
                                    "title": "Manipulating expressions"
                                }, 
                                {
                                    "description": "All the symbols you write in math are just a language or short-hand to represent real-world ideas.  In this tutorial, we'll get experience writing algebraic expressions to elegantly represent real-life ideas.", 
                                    "id": "writing-expressions-tutorial", 
                                    "title": "Writing and interpreting expressions"
                                }, 
                                {
                                    "description": "Much of algebra seems obsessed with \"doing the same thing to both sides\".  Why is this?  How can we develop an intuition for which algebraic operations are valid and which ones aren't?\n\nThis tutorial takes a high-level, conceptual walk-through of what an equation represents and why we do the same thing to both sides of it.", 
                                    "id": "algebra_why", 
                                    "title": "The why of algebra"
                                }, 
                                {
                                    "description": "This tutorial is a survey of all the core ideas in a traditional first-year algebra course.  It is by no means comprehensive (that's what the other 600+ videos are for), but it will hopefully whet your appetite for more algebra!", 
                                    "id": "yoga_plans", 
                                    "title": "Super Yoga plans"
                                }, 
                                {
                                    "description": "The core underlying concepts in algebra are variables, expressions, equations and inequalities.  You will see them throughout your math life (and even life after school).  \n\nThis tutorial won't give you all the tools that you'll later learn to analyze and interpret these ideas, but it'll get you started thinking about them.", 
                                    "id": "feel-for-equations-and-inequalit", 
                                    "title": "Getting a feel for equations and inequalities"
                                }, 
                                {
                                    "description": "You already know some basic algebra and you've been exposed to units for some time now.  In this tutorial, we meld these two ideas to think about units within the context of algebraic expressions.", 
                                    "id": "units-algebra", 
                                    "title": "Working with units algebraically"
                                }
                            ], 
                            "description": "Videos exploring why algebra was developed and how it helps us explain our world.", 
                            "id": "introduction-to-algebra", 
                            "title": "Introduction to algebra"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Algebra seems mysterious to me.  I really don't \"get\" what an equation represents.  Why do we do the same thing to both sides?\n\nThis tutorial is a conceptual journey through the basics of algebra.  It is made for someone just beginning their algebra adventure.  But even folks who feel pretty good that they know how to manipulate equations might pick up a new intuition or two.", 
                                    "id": "why-of-algebra", 
                                    "title": "The why of algebra"
                                }, 
                                {
                                    "description": "This tutorial is a survey of the major themes in basic algebra in five videos!  From basic equations to graphing to systems, it has it all.  Great for someone looking for a gentle, but broad understanding of the use of algebra.  Also great for anyone unsure of which gym plan they should pick!", 
                                    "id": "super-yoga", 
                                    "title": "Super Yoga plans"
                                }, 
                                {
                                    "description": "Like the \"Why of algebra\" and \"Super Yoga plans\" tutorials, we'll introduce you to the most fundamental ideas of what equations mean and how to solve them.  We'll then do a bunch of examples to make sure you're comfortable with things like 3x \u2013 7 = 8.  So relax, grab a cup of hot chocolate, and be on your way to becoming an algebra rockstar.\n\nAnd, by the way, in any of the \"example\" videos, try to solve the problem on your own before seeing how Sal does it.  It makes the learning better!", 
                                    "id": "equations_beginner", 
                                    "title": "Equations for beginners"
                                }, 
                                {
                                    "description": "Now that we are reasonably familiar with what a linear equation is and how we can solve them, let's apply these skills to tackling real-world problems.", 
                                    "id": "linear-equation-word-problems-tu", 
                                    "title": "Linear equation word problems"
                                }, 
                                {
                                    "description": "You've been through \"Equation examples for beginners\" and are feeling good.  Well, this tutorial continues that journey by addressing equations that are just a bit more fancy.  By the end of this tutorial, you really will have some of the core algebraic tools in your toolkit!", 
                                    "id": "basic-equation-practice", 
                                    "title": "More fancy equations for beginners"
                                }, 
                                {
                                    "description": "Not every linear equation has exactly one solution.  Some have no solutions and others might have an infinite number of solutions.  This tutorial will give you the intuition on when these different situations arise.", 
                                    "id": "solutions-linear-equations", 
                                    "title": "Solutions to linear equations"
                                }, 
                                {
                                    "description": "You feel comfortable solving for an unknown.  But life is all about stepping outside of your comfort zone--it's the only way you can grow!  This tutorial takes solving equations to another level by making things a little more abstract.  You will now solve for a variable, but it will be in terms of other variables.  Don't worry, we think you'll find it quite therapeutic once you get the hang of it.", 
                                    "id": "solving_for_variable", 
                                    "title": "Solving for a variable"
                                }, 
                                {
                                    "description": "You know that converting a fraction into a decimal can sometimes result in a repeating decimal.  For example: 2/3 = 0.666666..., and 1/7 = 0.142857142857... \n\nBut how do you convert a repeating decimal into a fraction?  As we'll see in this tutorial, a little bit of algebra magic can do the trick!", 
                                    "id": "conv_rep_decimals", 
                                    "title": "Converting repeating decimals to fractions"
                                }, 
                                {
                                    "description": "In 72 years, Sal will be 3 times as old as he is today (although he might not be... um... capable of doing much).  How old is Sal today?\n\nThese classic questions have plagued philosophers through the ages.  Actually, they haven't.  But they have plagued algebra students!  Even though few people ask questions like this in the real-world, these are strangely enjoyable problems.", 
                                    "id": "age_word_problems_tut", 
                                    "title": "Age word problems"
                                }, 
                                {
                                    "description": "You are absolutely tired of not knowing how to deal with equations that have absolute values in them.  Well, this tutorial might help.", 
                                    "id": "absolute-value-equations", 
                                    "title": "Absolute value equations"
                                }, 
                                {
                                    "description": "You feel good about your rapidly developing equation-solving ability.  Now you're ready to fully flex your brain.  \n\nIn this tutorial, we'll explore equations that don't look so simple at first, but that, with a bit of skill, we can turn into equations that don't cause any stress!  Have fun!", 
                                    "id": "complicated_equations", 
                                    "title": "Simplifying complicated equations"
                                }, 
                                {
                                    "description": "When solving equations, there is a natural hunger to figure out what an unknown is equal to.  This is especially the case if we want to evaluate an expression that the unknown is part of.  This tutorial exposes us to a class of solvable problems that challenges this hunger and forces us to be the thinking human beings that we are!\n\nIn case you're curious, these types of problems are known to show up on standardized exams to see if you are really a thinking human (as opposed to a robot possum).", 
                                    "id": "exp_unknown_vars", 
                                    "title": "Evaluating expressions with unknown variables"
                                }, 
                                {
                                    "description": "This tutorial is for you if you already have the basics of solving equations and are looking to put your newfound powers to work in more examples.", 
                                    "id": "More-equation-practice", 
                                    "title": "More equation practice"
                                }, 
                                {
                                    "description": "Some of Sal's oldest (and roughest) videos on algebra.  Great tutorial if you want to see what Khan Academy was like around 2006.  You might also like it if you feel like Sal has lost his magic now that he doesn't use the cheapest possible equipment to make the videos.", 
                                    "id": "old-school-equations", 
                                    "title": "Old school equations with Sal"
                                }
                            ], 
                            "description": "", 
                            "id": "solving-linear-equations-and-inequalities", 
                            "title": "Linear equations"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "In this tutorial you'll discover that much of the logic you've used to solve equations can also be applied to think about inequalities!", 
                                    "id": "inequalities", 
                                    "title": "Thinking algebraically about inequalities"
                                }, 
                                {
                                    "description": "You're starting to get comfortable with a world where everything isn't equal.  In this tutorial, we'll add more constraints to think of at the same time.  You may not realize it, but the ability to understand and manipulate compound and absolute value inequalities is key to many areas of science, engineering, and manufacturing (especially when tolerances are concerned)!", 
                                    "id": "compound_absolute_value_inequali", 
                                    "title": "Compound and absolute value inequalities"
                                }, 
                                {
                                    "description": "Algebra isn't just some voodoo concocted to keep you from running outside.  It is a way of representing logic and manipulating ideas.  This tutorial will have blood flowing to your brain in record quantities as you actually have to think about what the algebraic expressions and equations actually mean!", 
                                    "id": "structure-expressions-linear", 
                                    "title": "Structure in linear expressions"
                                }
                            ], 
                            "description": "Exploring a world where both sides aren't equal anymore!", 
                            "id": "linear_inequalities", 
                            "title": "Linear inequalities"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "How can we communicate exactly where something is in two dimensions?  Who was this Descartes character?  \n\nIn this tutorial, we cover the basics of the coordinate plane.  We then delve into graphing points and determining whether a point is a solution of an equation.  This will be a great tutorial experience if you are just starting to ramp up your understanding of graphing or need some fundamental review.", 
                                    "id": "coordinate-plane", 
                                    "title": "Coordinate plane"
                                }, 
                                {
                                    "description": "In this tutorial, we'll work through examples that show how a line can be viewed as all of coordinates whose x and y values satisfy a linear equation.  Likewise, a linear equation can be viewed as describing a relationship between the x and y values on a line.", 
                                    "id": "graphing_solutions2", 
                                    "title": "Graphing solutions to equations"
                                }, 
                                {
                                    "description": "There are many ways to graph a line and this tutorial covers one of the simpler ones.  Since you only need two points for a line, let's find what value an equation takes on when x = 0 (essentially the y-intercept) and what value it takes on when y = 0 (the x-intercept).  Then we can graph the line by going through those two points.", 
                                    "id": "graphing_with_intercepts", 
                                    "title": "x-intercepts and y-intercepts of linear functions"
                                }, 
                                {
                                    "description": "In this tutorial we'll think deeper about how one variable changes with respect to another.  Pay attention because you'll find that these ideas will keep popping up in your life!", 
                                    "id": "proportional-relationships", 
                                    "title": "Proportional relationships"
                                }, 
                                {
                                    "description": "In proportional relationships, the ratio between one variable and the other is always constant.  In the context of rate problems, this constant ratio can also be considered a rate of change.  This tutorial allows you dig deeper into this idea.", 
                                    "id": "rates-proportional", 
                                    "title": "Rates for proportional relationships"
                                }, 
                                {
                                    "description": "If you've ever struggled to tell someone just how steep something is, you'll find the answer here.  In this tutorial, we cover the idea of the slope of a line.  We also think about how slope relates to the equation of a line and how you can determine the slope or y-intercept given some clues.\n\nThis tutorial is appropriate for someone who understands the basics of graphing equations and want to dig a bit deeper.  After this tutorial, you will be prepared to start thinking deeper about the equation of a line.", 
                                    "id": "slope-and-intercepts", 
                                    "title": "Slope"
                                }, 
                                {
                                    "description": "Math is beautiful because there are so many way to appreciate the same relationship.  In this tutorial, we'll use our knowledge of slope to actually graph lines that have been expressed in slope-intercept form.", 
                                    "id": "graphing-slope-intercept", 
                                    "title": "Graphing linear equations in slope-intercept form"
                                }, 
                                {
                                    "description": "You know a bit about slope and intercepts.  Now we will develop that know-how even further to construct the equation of a line in slope-intercept form.\n\n", 
                                    "id": "equation-of-a-line", 
                                    "title": "Constructing equations in slope-intercept form"
                                }, 
                                {
                                    "description": "You know the slope of a line and you know that it contains a certain point.  Well, in this tutorial, you'll see that you can quickly take this information (and that knowledge the definition of what slope is) to construct the equation of this line in point-slope form!  You'll also manipulate between point-slope, slope-intercept and standard form.", 
                                    "id": "point-slope-form", 
                                    "title": "Point-slope form and standard form"
                                }, 
                                {
                                    "description": "You're familiar with graphing lines, slope and y-intercepts.  Now we are going to go further into analytic geometry by thinking about distances between points, midpoints, parallel lines and perpendicular ones.  Enjoy!", 
                                    "id": "more-analytic-geometry", 
                                    "title": "More analytic geometry"
                                }, 
                                {
                                    "description": "In this tutorial we'll see how to graph linear inequalities on the coordinate plane. We'll also learn how to determine if a particular point is a solution of an inequality.", 
                                    "id": "graphing-linear-inequalities", 
                                    "title": "Graphing linear inequalities"
                                }, 
                                {
                                    "description": "Use similar triangles to explain why the slope m is the same between any two distinct points on a non-vertical line in the coordinate plane.  We'll connect this idea to the equation y = mx for a line through the origin and the equation y = mx + b for a line intercepting the vertical axis at b (cc.8.ee.6).  ", 
                                    "id": "triangle-similarity-slope", 
                                    "title": "Triangle similarity and constant slope"
                                }, 
                                {
                                    "description": "Even when a function is nonlinear, we can calculate the average rate of change over an interval (we'll need calculus to calculate the rate of change at a particular value of the independent variable).  This tutorial will give you practice doing just that.", 
                                    "id": "average-rate-of-change", 
                                    "title": "Average rate of change"
                                }, 
                                {
                                    "description": "Much of the reason why math is interesting is that it can be used to model real-world phenomena.  In this tutorial, we'll do just this with graphs.", 
                                    "id": "equations-modeling", 
                                    "title": "Modeling with graphs"
                                }
                            ], 
                            "description": "Use the power of algebra to understand and interpret points and lines (something we typically do in geometry).  This will include slope and the equation of a line.", 
                            "id": "linear-equations-and-inequalitie", 
                            "title": "Graphing and analyzing linear functions"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Whether in the real world or a cliche fantasy one, systems of equations are key to solving super-important issues like \"the make-up of change in a troll's pocket\" or \"how can order the right amount of potato chips for a King's party.\"  Join us as we cover (and practice with examples and exercises) all of the major ways of solving a system: graphically, elimination, and substitution.  This tutorial will also help you think about when system might have no solution or an infinite number of solutions.  Very, very exciting stuff!", 
                                    "id": "systems-of-eq-overview", 
                                    "title": "A system for solving the King's problems"
                                }, 
                                {
                                    "description": "Have no time for trolls, kings and parrots and just want to get to the essence of system.  This might be a good tutorial for you.  As you can see, this stuff is so important that we're covering it in several tutorials!", 
                                    "id": "fast-systems-of-equations", 
                                    "title": "Super fast systems of equations"
                                }, 
                                {
                                    "description": "This tutorial focuses on solving systems graphically.  This is covered in several other tutorials, but this one gives you more examples than you can shake a chicken at.  Pause the videos and try to do them before Sal does.", 
                                    "id": "systems-through-examples", 
                                    "title": "Solving systems graphically"
                                }, 
                                {
                                    "description": "You know how to solve systems of equations (for the most part).  This tutorial will take things a bit deeper by exploring cases when you might have no solutions or an infinite number of them.", 
                                    "id": "systems-solutions", 
                                    "title": "Thinking about solutions to systems"
                                }, 
                                {
                                    "description": "This tutorial is focused on solving systems through substitution.  This is covered in several other tutorials, but this one focuses on substitution with more examples than you can shake a dog at.  As always, pause the video and try to solve before Sal does.", 
                                    "id": "systems-with-substitution", 
                                    "title": "Solving systems with substitution"
                                }, 
                                {
                                    "description": "You can solve a system of equations with either substitution or elimination.  This tutorial focuses with a ton of examples on elimination.  It is covered in other tutorials, but we give you far more examples here.  You'll learn best if you pause the videos and try to do the problem before Sal does.", 
                                    "id": "solving-systems-addition-elimination", 
                                    "title": "Solving systems with elimination (addition-elimination)"
                                }, 
                                {
                                    "description": "This tutorial doesn't involve talking parrots and greedy trolls, but it takes many of the ideas you might have learned in that tutorial and applies them to word problems.  These include rate problems, mixture problems, and others.  If you can pause and solve the example videos before Sal does, we'd say that you have a pretty good grasp of systems.  Enjoy!", 
                                    "id": "systems-word-problems", 
                                    "title": "Systems of equations word problems"
                                }, 
                                {
                                    "description": "You feel comfortable with systems of equations, but you begin to realize that the world is not always fair.  Not everything is equal!  In this short tutorial, we will explore systems of inequalities.  We'll graph them.  We'll think about whether a point satisfies them.  We'll even give you as much practice as you need.  All for 3 easy installments of... just kidding, it's free (although the knowledge obtained in priceless).  A good deal if we say so ourselves!", 
                                    "id": "system-of-inequalities", 
                                    "title": "Systems of inequalities"
                                }, 
                                {
                                    "description": "Two equations with two unknowns not challenging enough for you?  How about three equations with three unknowns?  Visualizing lines in 2-D too easy?  Well, now you're going to visualize intersecting planes in 3-D, baby. (Okay, we admit that it is weird for a website to call you \"baby.\")  Tired of linear systems?  Well, we might just bring a little nonlinearity into your life, honey. (You might want to brush up on your solving quadratics before tackling the non-linear systems.)  As always, try to pause the videos and do them before Sal does!", 
                                    "id": "fancier-systems", 
                                    "title": "Systems with three variables"
                                }, 
                                {
                                    "description": "In this tutorial, we'll use what we know about equations, inequalities and systems to answer some very practical real-world problems (and a few fake, impractical ones as well just for fun).", 
                                    "id": "modeling-constraints", 
                                    "title": "Modeling constraints"
                                }
                            ], 
                            "description": "Solving a system of equations or inequalities in two variables by elimination, substitution, and graphing.", 
                            "id": "systems-of-eq-and-ineq", 
                            "title": "Systems of equations and inequalities"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "\"Monomials\" sounds like a fancy word, but it just refers to single terms like \"4x\"  or \"8xy\"  or \"17x^2z\".  In this tutorial, we'll learn to multiply and divide them using ideas you're already familiar with (like exponent properties and greatest common factor).", 
                                    "id": "multiplying monomials", 
                                    "title": "Multiplying and dividing monomials"
                                }, 
                                {
                                    "description": "In this tutorial you'll learn that multiplying things like (4x-7)(-9x+5) just require the distributive property that you learned in elementary school.  We'll touch on the FOIL method because it seems to be covered in a lot of schools, but we don't like it (we don't think it is good to memorize processes without knowing the why).  ", 
                                    "id": "multiplying-binomials", 
                                    "title": "Multiplying binomials"
                                }, 
                                {
                                    "description": "You already know a bit about multiplying expressions.  We'll now reverse course and look at how to think about an expression as the product of simpler ones (just like we did when we find the factors of numbers).", 
                                    "id": "Factoring-simple-expressions", 
                                    "title": "Factoring simple expressions"
                                }, 
                                {
                                    "description": "Not only is factoring quadratic expressions (essentially second-degree polynomials) fun, but it is good for you.  It will allow you to analyze and solve a whole range of equations.  It will allow you to impress people at parties and move up the career ladder.  How exciting!", 
                                    "id": "factoring-quadratic-expressions", 
                                    "title": "Factoring quadratic expressions"
                                }, 
                                {
                                    "description": "You will encounter very factorable quadratics that don't always seem so.  This tutorial will expand your arsenal by exposing you to special products like difference-of-squares and perfect square quadratics.", 
                                    "id": "factoring-special-products", 
                                    "title": "Factoring special products"
                                }, 
                                {
                                    "description": "Factoring by grouping is probably the one thing that most people never really learn well.  Your fate doesn't have to be the same.  In this tutorial, you'll see how factoring by grouping can be used to factor a quadratic expression where the coefficient on the x^2 term is something other than 1?    ", 
                                    "id": "factoring-by-grouping", 
                                    "title": "Factoring by grouping"
                                }, 
                                {
                                    "description": "We'll now extend the application of our quadratic-factoring toolkit, by factoring expressions with two variables.  As we'll see, this is really just an extension of what you probably already know (or at least will know after working through this tutorial).  Onward!", 
                                    "id": "factoring-quadratics-in-two-vari", 
                                    "title": "Factoring quadratics in two variables"
                                }, 
                                {
                                    "description": "\"Polynomials\" sound like a fancy word, but you just have to break down the root words.  \"Poly\" means \"many\".  So we're just talking about \"many nomials\" and everyone knows what a \"nomial\" is.  Okay, most of us don't.  Well, a polynomials has \"many\" terms. \n\nFrom understanding what a \"term\" is to basic simplification, addition and subtraction of polynomials, this tutorial will get you very familiar with the world of many \"nomials.\" :)", 
                                    "id": "polynomial_basics", 
                                    "title": "Polynomial basics"
                                }, 
                                {
                                    "description": "You'll see in this tutorial that multiplying polynomials is just an extension of the same distributive property that you've already learned to multiply simpler expression (that's why we think FOIL is lame--it doesn't generalize and it is more memorization than real understanding).", 
                                    "id": "multiplying_polynomials", 
                                    "title": "Multiplying polynomials"
                                }
                            ], 
                            "description": "This topic will add a ton of tools to your algebraic toolbox.  You'll be able to multiply any expression and learn to factor a bunch a well.  This will allow you to solve a broad array of problems in algebra.", 
                            "id": "multiplying-factoring-expression", 
                            "title": "Multiplying and factoring expressions"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Let's explore one of the most fundamental ways to solve a quadratic equation when it is already written in terms of a square of an expression in x--solve for the expression and take the square root.  As we'll see, equations are not always in this form, and that is where completing the square--which puts equations in this form--is essential!", 
                                    "id": "quadratics-square-root", 
                                    "title": "Solving quadratics by taking square root"
                                }, 
                                {
                                    "description": "Just saying the word \"quadratic\" will make you feel smart and powerful.  Try it.  Imagine how smart and powerful you would actually be if you know what a quadratic is.  Even better, imagine being able to completely dominate these \"quadratics\" with new found powers of factorization.  Well, dream no longer.\n\nThis tutorial will be super fun.  Just bring to it your equation solving skills, your ability to multiply binomials and a non-linear way of thinking!", 
                                    "id": "factoring_quadratics", 
                                    "title": "Solving quadratics by factoring"
                                }, 
                                {
                                    "description": "You're already familiar with factoring quadratics, but have begun to realize that it only is useful in certain cases.  Well, this tutorial will introduce you to something far more powerful and general.  Even better, it is the bridge to understanding and proving the famous quadratic formula.\n\nWelcome to the world of completing the square!", 
                                    "id": "completing_the_square", 
                                    "title": "Completing the square"
                                }, 
                                {
                                    "description": "Probably one of the most famous tools in mathematics, the quadratic formula (a.k.a. quadratic equation) helps you think about the roots of ANY quadratic (even ones that have no real roots)!  As you'll see, it is just the by-product of completing the square, but understanding and applying the formula will take your algebra skills to new heights.\n\nIn theory, one could apply the quadratic formula in a brainless way without understanding factoring or completing the square, but that's lame and uninteresting.  We recommend coming to this tutorial with a solid background in both of those techniques.  Have fun!", 
                                    "id": "quadratic-formula", 
                                    "title": "The quadratic formula (quadratic equation)"
                                }, 
                                {
                                    "description": "Tired of lines?  Not sure if a parabola is a disease of the gut or a new mode of transportation? Ever wondered what would happen to the graph of a function if you stuck an x\u00b2 someplace?  Well, look no further.\n\nIn this tutorial, we will study the graphs of quadratic functions (parabolas), including their foci and whatever the plural of directrix is.", 
                                    "id": "solving_graphing_quadratics", 
                                    "title": "Graphing quadratics"
                                }, 
                                {
                                    "description": "You are familiar with factoring quadratic expressions and solving quadratic equations.  Well, as you might guess, not everything in life has to be equal.\n\nIn this short tutorial we will look at quadratic inequalities.", 
                                    "id": "quadratic_inequalities", 
                                    "title": "Quadratic inequalities"
                                }, 
                                {
                                    "description": "This tutorial has a bunch of extra, but random, videos on quadratics.  A completely optional tutorial that you may or may not want to look at.  If you do, watch it last.  There are some Sal oldies here and some random examples.", 
                                    "id": "quadratic_odds_ends", 
                                    "title": "Quadratic odds and ends"
                                }
                            ], 
                            "description": "In this topic, we'll analyze, graph and solve quadratic equations.", 
                            "id": "quadratics", 
                            "title": "Quadratic equations"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "In this tutorial, we're going to significantly deepen our understanding of the world of exponents.  In particular, we'll look at what it means to raise something to a negative exponent and also think about various exponent properties for rewriting expressions.", 
                                    "id": "alg-integer-exponents", 
                                    "title": "Properties of exponents"
                                }, 
                                {
                                    "description": "In this tutorial, you will learn about how to manipulate expressions with exponents in them.  We'll give lots of example to make sure you see a lot of scenarios.  For optimal learning (and fun), pause the video before Sal does an example.", 
                                    "id": "exponent-properties-algebra", 
                                    "title": "Exponent properties examples with variables"
                                }, 
                                {
                                    "description": "If you're familiar with taking square roots and cube roots (and other roots), then you're ready to see that we can also express these as exponents in ways that are consistent with the exponent properties you know and love!", 
                                    "id": "fractional-exponents-tut", 
                                    "title": "Fractional exponents"
                                }, 
                                {
                                    "description": "You already know what square roots and cube roots are, now you will apply that knowledge to simplify variable expressions that involve radicals.", 
                                    "id": "simplifying-radical-expressions", 
                                    "title": "Simplifying radical expressions"
                                }, 
                                {
                                    "description": "You're enjoying algebra and equations, but you miss radicals.  Wouldn't it be unbelievably awesome if you could solve equations with radicals in them.  Well, your dreams can come true.\n\nIn this tutorial, we work through a bunch of examples to help you understand how to solve radical equations.  As always, pause the videos and try to solve the example before Sal does.", 
                                    "id": "radical_equations", 
                                    "title": "Radical equations"
                                }
                            ], 
                            "description": "Solving exponential and radical expressions and equations. Using scientific notation and significant figures.", 
                            "id": "exponent-equations", 
                            "title": "Exponent expressions and equations"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Relationships can be any association between sets of numbers while functions have only one output for a given input.  This tutorial works through a bunch of examples of testing whether something is a valid function.  As always, we really encourage you to pause the videos and try the problems before Sal does!", 
                                    "id": "relationships_functions", 
                                    "title": "Function introduction"
                                }, 
                                {
                                    "description": "Not all relationships are functions.  In this tutorial, you'll learn which are!", 
                                    "id": "recognizing-functions", 
                                    "title": "Recognizing functions"
                                }, 
                                {
                                    "description": "What values can you and can you not input into a function?  What values can the function output?  The domain is the set of values that the function is defined for (i.e., the values that you can input into a function).  The range is the set of values that the function output can take on.\n\nThis tutorial covers the ideas of domain and range through multiple worked examples.  These are really important ideas as you study higher mathematics.", 
                                    "id": "domain_and_range", 
                                    "title": "Domain and range"
                                }, 
                                {
                                    "description": "Whether you are talking about how force relates to acceleration or how the cost of movie tickets relates to the number of people going, it is not uncommon in this universe for things to vary directly.  Similarly, when you are, say, talking about how hunger might relate to seeing roadkill, things can vary inversely.\n\nThis tutorial digs deeper into these ideas with a bunch of examples of direct and inverse variation.", 
                                    "id": "direct_inverse_variation", 
                                    "title": "Direct and inverse variation"
                                }, 
                                {
                                    "description": "You've already graphed functions when you graphed lines and curves in other topics so this really isn't anything new.  Now we'll do a few more examples in this tutorial, but we'll use the function notation to make things a bit more explicit.", 
                                    "id": "graphing_functions", 
                                    "title": "Graphing functions"
                                }, 
                                {
                                    "description": "This is a super fun tutorial where we'll evaluate expressions that involve functions.  We'll add, subtract, multiply and divide them.  We'll also do composite functions which involves taking the output of one function to be the input of another one!\n\nAs always, pause the video and try the problem before Sal does!", 
                                    "id": "eval-function-expressions", 
                                    "title": "Evaluating function expressions"
                                }, 
                                {
                                    "description": "Functions associate a set of inputs with a set of outputs (in fancy language, they \"map\" one set to another).  But can we go the other way around?  Are there functions that can start with the outputs as inputs and produce the original inputs as outputs?  Yes, there are!  They are called function inverses!\n\nThis tutorial works through a bunch of examples to get you familiar with the world of function inverses.", 
                                    "id": "function_inverses", 
                                    "title": "Function inverses"
                                }, 
                                {
                                    "description": "Are you bored of the traditional operators of addition, subtraction, multiplication and division?  Do even exponents seem a little run-of-the-mill?\n\nWell in this tutorial, we will--somewhat arbitrarily--define completely new operators and notation (which are essentially new function definitions without the function notation).  Not only will this tutorial expand your mind, it could be the basis of a lot of fun at your next dinner party!", 
                                    "id": "new_operators", 
                                    "title": "New operator definitions"
                                }, 
                                {
                                    "description": "These oldie-but-maybe-goodies are the original function videos that Sal made years ago for his cousins.  Despite the messy handwriting, some people claim that they like these better than the new ones (they claim that there is a certain charm to them).  We'll let you decide.", 
                                    "id": "classic-function-videos", 
                                    "title": "Classic function videos"
                                }, 
                                {
                                    "description": "Now that you know how to solve linear, quadratic and exponential equations, we'll apply these incredible skills to a wide-range of real-world (and sometimes not-so-real-world) situations.", 
                                    "id": "one-variable-modeling", 
                                    "title": "Modeling with one-variable equations and inequalities"
                                }
                            ], 
                            "description": "Identifying, solving, and graphing various types of functions.", 
                            "id": "algebra-functions", 
                            "title": "Functions"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "You remember a thing or two about ratios and proportions from you pre-algebra days.  Well, how can we use these same ideas to solve problems in algebra.\n\nThis tutorial re-introduces ratios in an algebraic context and helps us solve some awesome problems!", 
                                    "id": "ratios_algebra", 
                                    "title": "Ratios and proportions"
                                }, 
                                {
                                    "description": "In this tutorial, we will explore more advanced examples involving ratios, proportions, and rates.", 
                                    "id": "advanced-ratios", 
                                    "title": "Advanced ratios, proportions, and rates"
                                }, 
                                {
                                    "description": "In this tutorial, we'll use the powers of algebra to actually prove what we've always suspected to be true of rational and irrational numbers!", 
                                    "id": "alg-rational-irrational-numbers", 
                                    "title": "Rational and irrational numbers"
                                }
                            ], 
                            "description": "What ratios and proportions are.  Using them to solve problems in the real world.", 
                            "id": "ratio-proportion-topic", 
                            "title": "Ratios and proportions"
                        }
                    ], 
                    "description": "Conceptual videos and worked examples from basic algebra.", 
                    "id": "algebra", 
                    "title": "Algebra I"
                }, 
                {
                    "children": [
                        {
                            "description": "Roughly 2400 years ago, Euclid of Alexandria wrote Elements which served as the world's geometry textbook until recently.  Studied by Abraham Lincoln in order to sharpen his mind and truly appreciate mathematical deduction, it is still the basis of what we consider a first year course in geometry.\n\nThis tutorial gives a bit of this background and then lays the conceptual foundation of points, lines, circles and planes that we will use as we journey through the world of Euclid.", 
                            "id": "intro_euclid", 
                            "title": "Introduction to Euclidean geometry"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "This tutorial will define what an angle is and help us think about how to measure them.  If you're new to angles, this is a great place to start.", 
                                    "id": "Angle_basics", 
                                    "title": "Angle basics and measurement"
                                }, 
                                {
                                    "description": "Welcome.  I'd like to introduce you to Mr. Angle.  Nice to meet you.  So nice to meet you.  \n\nThis tutorial introduces us to angles.  It includes how we measure them, how angles relate to each other and properties of angles created from various types of intersecting lines.  Mr. Angle is actually far more fun than you might initially presume him to be.", 
                                    "id": "ang_intro", 
                                    "title": "Angles between intersecting and parallel lines"
                                }, 
                                {
                                    "description": "Do the angles in a triangle always add up to the same thing?  Would I ask it if they didn't?  What do we know about the angles of a triangle if two of the sides are congruent (an isosceles triangle) or all three are congruent (an equilateral)?  This tutorial is the place to find out.", 
                                    "id": "triang_prop_tut", 
                                    "title": "Angles with triangles and polygons"
                                }, 
                                {
                                    "description": "These are some of the classic, original angle video that Sal had done way back when (like 2007).  Other tutorials are more polished than this one, but this one has charm.  Also not bad if you're looking for more examples of angles between intersected lines, transversals and parallel lines.", 
                                    "id": "old_angles", 
                                    "title": "Sal's old angle videos"
                                }, 
                                {
                                    "description": "In this tutorial we'll look at the most famous types of angle-pairs--complementary and supplementary angles.  This aren't particularly deep concepts, but you'll find they do come in handy!", 
                                    "id": "complementary-supplementary-angl", 
                                    "title": "Complementary and supplementary angles"
                                }
                            ], 
                            "description": "This topic continues our journey through the world of Euclid by helping us understand angles and how they can relate to each other.", 
                            "id": "parallel-and-perpendicular-lines", 
                            "title": "Angles and intersecting lines"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Two figures are congruent if you can go from one to another through some combination of translations, reflections and rotations.  In this tutorial, we'll really internalize this by working through the actual transformations.", 
                                    "id": "transformations-congruence", 
                                    "title": "Transformations and congruence"
                                }, 
                                {
                                    "description": "We begin to seriously channel Euclid in this tutorial to really, really (no, really) prove things--in particular, that triangles are congruents.  You'll appreciate (and love) what rigorous proofs are.  It will sharpen your mind and make you a better friend, relative and citizen (and make you more popular in general).  Don't have too much fun.", 
                                    "id": "cong_triangle", 
                                    "title": "Congruence postulates"
                                }, 
                                {
                                    "description": "This tutorial uses our understanding of congruence postulates to prove some neat properties of isosceles and equilateral triangles.", 
                                    "id": "isoscleles_equil", 
                                    "title": "Congruence and isosceles and equilateral triangles"
                                }
                            ], 
                            "description": "If you can take one figure and flip, shift and rotate (not resize) it to be identical to another figure, then the two figures are congruent.  This topic explores this foundational idea in geometry.", 
                            "id": "congruent-triangles", 
                            "title": "Congruence"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Two figures are similar if you can get from one to another through some combinations of translations, reflections, rotations AND DILATIONS (so you can scale up and down).  This tutorial helps give us an intuition for this.", 
                                    "id": "similarity-and-transformations", 
                                    "title": "Similarity and transformations"
                                }, 
                                {
                                    "description": "This tutorial explains a similar (but not congruent) idea to congruency (if that last sentence made sense, you might not need this tutorial).  Seriously, we'll take a rigorous look at similarity and think of some reasonable postulates for it.  We'll then use these to prove some results and solve some problems.  The fun must not stop!", 
                                    "id": "triangle_similarlity", 
                                    "title": "Triangle similarity"
                                }, 
                                {
                                    "description": "We spend a lot of time in geometry proving that triangles are congruent or similar.  We now apply this ability to some really interesting problems (seriously, these are fun)!", 
                                    "id": "cc-solving-prob-similar-tri", 
                                    "title": "Solving problems with similar and congruent triangles"
                                }, 
                                {
                                    "description": "These videos may look similar (pun-intended) to videos in another playlist but they are older, rougher and arguably more charming.  These are some of the original videos that Sal made on similarity.  They are less formal than those in the \"other\" similarity tutorial, but, who knows, you might like them more.", 
                                    "id": "old_school_similarity", 
                                    "title": "Old school similarity"
                                }
                            ], 
                            "description": null, 
                            "id": "similarity", 
                            "title": "Similarity"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Named after the Greek philosopher who lived nearly 2600 years ago, the Pythagorean theorem is as good as math theorems get (Pythagoras also started a religious movement).  It's simple.  It's beautiful.  It's powerful.\n\nIn this tutorial, we will cover what it is and how it can be used.  We have another tutorial that gives you as many proofs of it as you might need.", 
                                    "id": "pyth_theor", 
                                    "title": "Pythagorean theorem"
                                }, 
                                {
                                    "description": "The Pythagorean theorem is one of the most famous ideas in all of mathematics.  This tutorial proves it.  Then proves it again... and again... and again.  More than just satisfying any skepticism of whether the Pythagorean theorem is really true (only one proof would be sufficient for that), it will hopefully open your mind to new and beautiful ways to prove something very powerful.", 
                                    "id": "pythagorean_proofs", 
                                    "title": "Pythagorean theorem proofs"
                                }, 
                                {
                                    "description": "We hate to pick favorites, but there really are certain right triangles that are more special than others.  In this tutorial, we pick them out, show why they're special, and prove it!  These include 30-60-90 and 45-45-90 triangles (the numbers refer to the measure of the angles in the triangle).", 
                                    "id": "special_right_triangles", 
                                    "title": "Special right triangles"
                                }, 
                                {
                                    "description": "In this tutorial, you will learn all the trigonometry that you are likely to remember in ten years (assuming you are a lazy non-curious, non-lifelong learner).  But even in that non-ideal world where you forgot everything else, you'll be able to do more than you might expect with the concentrated knowledge you are about to get.", 
                                    "id": "cc-geometry-trig", 
                                    "title": "Sine, cosine and tangent trigonometric functions"
                                }, 
                                {
                                    "description": "In this tutorial, we will build on our understanding of similarity to get a deeper appreciation for the motivation behind trigonometric ratios and relationships.", 
                                    "id": "cc-geometry-trig-similarity", 
                                    "title": "Trig ratios and similarity"
                                }
                            ], 
                            "description": "Triangles are not always right (although they are never wrong), but when they are it opens up an exciting world of possibilities.  Not only are right triangles cool in their own right (pun intended), they are the basis of very important ideas in analytic geometry (the distance between two points in space) and trigonometry.", 
                            "id": "right_triangles_topic", 
                            "title": "Right triangles and trigonometry"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "You first learned about perimeter and area when you were in grade school.  In this tutorial, we will revisit those ideas with a more mathy lense.  We will use our prior knowledge of congruence to really start to prove some neat (and useful) results (including some that will be useful in our study of similarity).", 
                                    "id": "perimeter_area_tutorial", 
                                    "title": "Perimeter and area of triangles"
                                }, 
                                {
                                    "description": "The triangle inequality theorem is, on some level, kind of simple.  But, as you'll see as you go into high level mathematics, it is often used in fancy proofs.\n\nThis tutorial introduces you to what it is and gives you some practice understanding the constraints on the dimensions of a triangle.", 
                                    "id": "triangle_inequality_theorem", 
                                    "title": "Triangle inequality theorem"
                                }, 
                                {
                                    "description": "Named after Helge von Koch, the Koch snowflake is one of the first fractals to be discovered. It is created by adding smaller and smaller equilateral bumps to an existing equilateral triangle.  Quite amazingly, it produces a figure of infinite perimeter and finite area!", 
                                    "id": "koch_snowflake", 
                                    "title": "Koch snowflake fractal"
                                }, 
                                {
                                    "description": "Named after Heron of Alexandria, Heron's formula is a power (but often overlooked) method for finding the area of ANY triangle.  In this tutorial we will explain how to use it and then prove it!", 
                                    "id": "heron_formula_tutorial", 
                                    "title": "Heron's formula"
                                }, 
                                {
                                    "description": "Circles are everywhere.  How can we measure how big they are?  Well, we could think about the distance around the circle (circumference).  Another option would be to think about how much space it takes up on our paper (area).  Have fun!", 
                                    "id": "circum_area_circles", 
                                    "title": "Circumference and area of circles"
                                }, 
                                {
                                    "description": "Not everything in the world is a rectangle, circle or triangle.  In this tutorial, we give you practice at finding the perimeters and areas of these less-than-standard shapes!", 
                                    "id": "area_non_standard", 
                                    "title": "Perimeter and area of non-standard shapes"
                                }, 
                                {
                                    "description": "Tired of perimeter and area and now want to measure 3-D space-take-upness.  Well you've found the right tutorial.  Enjoy!", 
                                    "id": "volume_tutorial", 
                                    "title": "Volume and surface area"
                                }, 
                                {
                                    "description": "", 
                                    "id": "cross-sections", 
                                    "title": "Cross sections of 3D objects"
                                }
                            ], 
                            "description": "A broad set of tutorials covering perimeter area and volume with and without algebra.", 
                            "id": "basic-geometry", 
                            "title": "Perimeter, area, and volume"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "This tutorial will review some of the basic of circles and then think about lengths of arcs and areas of sectors.", 
                                    "id": "circles", 
                                    "title": "Circle arcs and sectors"
                                }, 
                                {
                                    "description": "We'll now dig a bit deeper in our understanding of circles by looking at central, inscribed and circumscribed angles.  This is fun and beautiful as is, but you'll also see that it shows up on a lot of math standardized tests. Why do people like to put geometry like this on standardized tests?  Because it shows deductive reasoning skills which are super important in every walk of life!", 
                                    "id": "central-inscribed-circumscribed", 
                                    "title": "Central, inscribed and circumscribed angles"
                                }, 
                                {
                                    "description": "You know that a circle can be viewed as the set of all points that whose distance from the center is equal to the radius.  In this tutorial, we use this information and the Pythagorean Theorem to derive the equation of a circle.", 
                                    "id": "equation-of-a-circle", 
                                    "title": "Equation of a circle"
                                }, 
                                {
                                    "description": "This more advanced (and very optional) tutorial is fun to look at for enrichment.  It builds to figuring out the formula for the area of a triangle inscribed in a circle!", 
                                    "id": "area-inscribed-triangle", 
                                    "title": "Area of inscribed triangle"
                                }, 
                                {
                                    "description": "Let's use what we know about geometry to answer some really, really interesting questions.", 
                                    "id": "geometric-models", 
                                    "title": "Geometric models"
                                }
                            ], 
                            "description": "", 
                            "id": "cc-geometry-circles", 
                            "title": "Circles"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "In this tutorial, we study lines that are perpendicular to the sides of a triangle and divide them in two (perpendicular bisectors).  As we'll prove, they intersect at a unique point called the cicumcenter (which, quite amazingly, is equidistant to the vertices).  We can then create a circle (circumcircle) centered at this point that goes through all the vertices. \n\nThis tutorial is the extension of the core narrative of the Geometry \"course\".  After this, you might want to look at the tutorial on angle bisectors.", 
                                    "id": "perpendicular_bisectors", 
                                    "title": "Perpendicular bisectors"
                                }, 
                                {
                                    "description": "This tutorial experiments with lines that divide the angles of a triangle in two (angle bisectors).  As we'll prove, all three angle bisectors actually intersect at one point called the incenter (amazing!).  We'll also prove that this incenter is equidistant from the sides of the triangle (even more amazing!).  This allows us to create a circle centered at the incenter that is tangent to the sides of the triangle (not surprisingly called the \"incircle\").", 
                                    "id": "angle_bisectors", 
                                    "title": "Angle bisectors"
                                }, 
                                {
                                    "description": "You've explored perpendicular bisectors and angle bisectors, but you're craving to study lines that intersect the vertices of a a triangle AND bisect the opposite sides.  Well, you're luck because that (medians) is what we are going to study in this tutorial.  We'll prove here that the medians intersect at a unique point (amazing!) called the centroid and divide the triangle into six mini triangles of equal area (even more amazing!).  The centroid also always happens to divide all the medians in segments with lengths at a 1:2 ration (stupendous!).", 
                                    "id": "medians_centroids", 
                                    "title": "Medians and centroids"
                                }, 
                                {
                                    "description": "Ok.  You knew triangles where cool, but you never imagined they were this cool!  Well, this tutorial will take things even further.  After perpendicular bisectors, angle bisector and medians, the only other thing (that I can think of) is a line that intersects a vertex and the opposite side (called an altitude).  As we'll see, these are just as cool as the rest and, as you may have guessed, intersect at a unique point called the orthocenter (unbelievable!).", 
                                    "id": "altitudes", 
                                    "title": "Altitudes"
                                }, 
                                {
                                    "description": "This tutorial brings together all of the major ideas in this topic.  First, it starts off with a light-weight review of the various ideas in the topic.  It then goes into a heavy-weight proof of a truly, truly, truly amazing idea.  It was amazing enough that orthocenters, circumcenters, and centroids exist , but we'll see in the videos on Euler lines that they sit on the same line themselves (incenters must be feeling lonely)!!!!!!!", 
                                    "id": "triangle_property_review", 
                                    "title": "Bringing it all together"
                                }
                            ], 
                            "description": "You probably like triangles.  You think they are useful.  They show up a lot.  What you'll see in this topic is that they are far more magical and mystical than you ever imagined!", 
                            "id": "triangle-properties", 
                            "title": "Special properties and parts of triangles"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Not all things with four sides have to be squares or rectangles!  We will now broaden our understanding of quadrilaterals!", 
                                    "id": "quadrilaterals", 
                                    "title": "Quadrilaterals"
                                }
                            ], 
                            "description": "", 
                            "id": "quadrilaterals-and-polygons", 
                            "title": "Quadrilaterals"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Let's get an intuitive understanding for symmetry of two dimensional shapes.", 
                                    "id": "transformations-symmetry", 
                                    "title": "Symmetry"
                                }, 
                                {
                                    "description": "Let's use some pretty cool software widgets to see how we can transform a shape through translations, rotations, dilations and reflections.", 
                                    "id": "exploring-rigid-transformations", 
                                    "title": "Exploring rigid transformations"
                                }, 
                                {
                                    "description": "We understand the idea of scaling/dilation from everyday life (hey, let's make it bigger or smaller keeping the same proportions!).  In this tutorial, you'll understand this type of transformation in a much, much deeper way.", 
                                    "id": "dilations-scaling", 
                                    "title": "Dilations or scaling around a point"
                                }, 
                                {
                                    "description": "Let's continue our deep voyage through the world of transformations by thinking about how points map to each other after a transformation.", 
                                    "id": "coordinate-plane-transformations", 
                                    "title": "Transformations on the coordinate plane"
                                }
                            ], 
                            "description": "Let's think more visually about things like shifts, rotations, scaling and symmetry.", 
                            "id": "transformations", 
                            "title": "Transformations"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "You are familiar with the ideas of slope and distance on the coordinate plane.  You also feel comfortable with congruence an similarity and many of the other core ideas in Euclidean geometry.  In this, tutorial, Descartes and Euclid are forced to work together as we tackle geometry problems on the coordinate plane!", 
                                    "id": "geometry-problems-coordinate-pla", 
                                    "title": "Geometry problems on the coordinate plane"
                                }, 
                                {
                                    "description": "We are now going to leverage our understanding of the coordinate plane to think about distances between points and ratios of lengths of segments between points.", 
                                    "id": "cc-distances-between-points", 
                                    "title": "Distances between points"
                                }
                            ], 
                            "description": "", 
                            "id": "analytic-geometry-topic", 
                            "title": "Analytic geometry"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "With just a compass and a straightedge  (or virtual versions of them), you'll be amazed by how many geometric shapes you can construct perfectly.  This tutorial gets you started with the building block of how to bisect angle and lines (and how to construct perpendicular bisectors of lines).", 
                                    "id": "geo-bisectors", 
                                    "title": "Constructing bisectors of lines and angles"
                                }, 
                                {
                                    "description": "Have you ever wondered how people would draw a square, equilateral triangle or even hexagon before there were computers?  Well, now you're going to do just that (ironically, with a computer).  Using our virtual compass and straightedge, you'll construct several regular shapes (by inscribing them inside circles).", 
                                    "id": "polygons-inscribed-in-circles", 
                                    "title": "Constructing regular polygons inscribed in circles"
                                }, 
                                {
                                    "description": "In our study of triangles, we spent a decent amount of time think about incenters (the intersections of the angle bisectors) and circumcenters (the intersections of the perpendicular bisectors).  We'll now leverage this knowledge to actually construct circle inscribed and circumscribed about a triangle using only a compass and straightedge (actually virtual versions of them).", 
                                    "id": "circum-in-circles", 
                                    "title": "Constructing circumcircles and incircles"
                                }, 
                                {
                                    "description": "", 
                                    "id": "constructing-tangents", 
                                    "title": "Constructing a line tangent to a circle"
                                }
                            ], 
                            "description": "We now have fancy computers to help us perfectly draw things, but have you ever wondered how people drew perfect circles or angle bisectors or perpendicular bisectors back in the day.  Well this tutorial will have you doing just as your grandparents did (actually, a little different since you'll still be using a computer to draw circles and lines with a virtual compass and straightedge).", 
                            "id": "geometric-constructions", 
                            "title": "Geometric constructions"
                        }, 
                        {
                            "description": "Sal does the 80 problems from the released questions from the California Standards Test for Geometry.  Basic understanding of Algebra I necessary.", 
                            "id": "geometry-worked-examples", 
                            "title": "Worked examples"
                        }
                    ], 
                    "description": "This is a first year, high-school level course on Geometry (which is based on Euclid's elements).  It revisits many of the basic geometrical concepts studied in earlier courses, but addresses them with more mathematical rigor. There is strong focus on proving theorems and results from basic postulates.", 
                    "id": "geometry", 
                    "title": "Geometry"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "Whether in the real world or a cliche fantasy one, systems of equations are key to solving super-important issues like \"the make-up of change in a troll's pocket\" or \"how can order the right amount of potato chips for a King's party.\"  Join us as we cover (and practice with examples and exercises) all of the major ways of solving a system: graphically, elimination, and substitution.  This tutorial will also help you think about when system might have no solution or an infinite number of solutions.  Very, very exciting stuff!", 
                                    "id": "systems_tutorial_precalc", 
                                    "title": "Solving systems of equations for the king"
                                }, 
                                {
                                    "description": "You feel comfortable with systems of equations, but you begin to realize that the world is not always fair.  Not everything is equal!  In this short tutorial, we will explore systems of inequalities.  We'll graph them.  We'll think about whether a point satisfies them.  We'll even give you as much practice as you need.  All for 3 easy installments of... just kidding, it's free (although the knowledge obtained in priceless).  A good deal if we say so ourselves!", 
                                    "id": "systems_inequalities_precalc", 
                                    "title": "Systems of inequalities"
                                }, 
                                {
                                    "description": "Tired of linear systems?  Well, we might just bring a little nonlinearity into your life, honey. (You might want to brush up on your solving quadratics before tackling the non-linear systems.)  As always, try to pause the videos and do them before Sal does!", 
                                    "id": "non-linear-systems-tutorial", 
                                    "title": "Non-linear systems of equations"
                                }
                            ], 
                            "description": "What happens when we have many variables but also many constraints.", 
                            "id": "systems_eq_ineq", 
                            "title": "Systems of equations and inequalities"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Relationships can be any association between sets of numbers while functions have only one output for a given input.  This tutorial works through a bunch of examples of testing whether something is a valid function.  As always, we really encourage you to pause the videos and try the problems before Sal does!", 
                                    "id": "copy-of-relationships_functions-2014-03-28T18:09:49.924Z", 
                                    "title": "Function introduction"
                                }, 
                                {
                                    "description": "We'll now see what it means to add, subtract, multiply and divide functions!", 
                                    "id": "function_expressions", 
                                    "title": "Function expressions"
                                }, 
                                {
                                    "description": "What values can you and can you not input into a function?  What values can the function output?  The domain is the set of values that the function is defined for (i.e., the values that you can input into a function).  The range is the set of values that the function output can take on.\n\nThis tutorial covers the ideas of domain and range through multiple worked examples.  These are really important ideas as you study higher mathematics.", 
                                    "id": "domain_range", 
                                    "title": "Domain and range"
                                }, 
                                {
                                    "description": "Not all relationships are functions.  In this tutorial, you'll learn which are!", 
                                    "id": "copy-of-recognizing-functions-2014-03-28T18:10:35.918Z", 
                                    "title": "Recognizing functions"
                                }, 
                                {
                                    "description": "", 
                                    "id": "composing-functions", 
                                    "title": "Composing functions"
                                }, 
                                {
                                    "description": "Functions associate a set of inputs with a set of outputs (in fancy language, they \"map\" one set to another).  But can we go the other way around?  Are there functions that can start with the outputs as inputs and produce the original inputs as outputs?  Yes, there are!  They are called function inverses!\n\nThis tutorial works through a bunch of examples to get you familiar with the world of function inverses.", 
                                    "id": "fucntion_inverses", 
                                    "title": "Function inverses"
                                }, 
                                {
                                    "description": "In this tutorial, we will get practice looking at wackier functions that are defined interval by interval (or piece by piece)!", 
                                    "id": "piecewise-functions-tutorial", 
                                    "title": "Piecewise functions"
                                }, 
                                {
                                    "description": "", 
                                    "id": "shifting-reflecting-functions", 
                                    "title": "Shifting and reflecting functions"
                                }, 
                                {
                                    "description": "You know a function when you see one, but are curious to start looking deeper at their properties. Some functions seem to be mirror images around the y-axis while others seems to be flipped mirror images while others are neither. How can we shift and reflect them?  \n\nThis tutorial addresses these questions by covering even and odd functions.  It also covers how we can shift and reflect them.  Enjoy!", 
                                    "id": "analyzing_functions", 
                                    "title": "Properties and features of functions"
                                }, 
                                {
                                    "description": "In this tutorial, we'll dive deeper into actually thinking about what functions represent and how one function compares to another.", 
                                    "id": "comparing-interpreting-functions", 
                                    "title": "Comparing and interpreting functions"
                                }, 
                                {
                                    "description": "In second grade you may have raised your hand in class and asked what you get when you divide by zero.  The answer was probably \"it's not defined.\"  In this tutorial we'll explore what that (and \"indeterminate\") means and why the math world has left this gap in arithmetic. (They could define something divided by 0 as 7 or 9 or 119.57 but have decided not to.)", 
                                    "id": "undefined_indeterminate", 
                                    "title": "Undefined and indeterminate answers"
                                }, 
                                {
                                    "description": "In this tutorial, we'll start to use and define functions in more \"mathy\" or formal ways.", 
                                    "id": "mathy-functions", 
                                    "title": "More mathy functions"
                                }
                            ], 
                            "description": "Revisiting what a function is and how we can define and visualize one.", 
                            "id": "functions_and_graphs", 
                            "title": "Functions and their graphs"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Just saying the word \"quadratic\" will make you feel smart and powerful.  Try it.  Imagine how smart and powerful you would actually be if you know what a quadratic is.  Even better, imagine being able to completely dominate these \"quadratics\" with new found powers of factorization.  Well, dream no longer.\n\nThis tutorial will be super fun.  Just bring to it your equation solving skills, your ability to multiply binomials and a non-linear way of thinking!", 
                                    "id": "quad_factoring", 
                                    "title": "Factoring quadratics"
                                }, 
                                {
                                    "description": "You're already familiar with factoring quadratics, but have begun to realize that it only is useful in certain cases.  Well, this tutorial will introduce you to something far more powerful and general.  Even better, it is the bridge to understanding and proving the famous quadratic formula.\n\nWelcome to the world of completing the square!", 
                                    "id": "quad_formula_tutorial", 
                                    "title": "Completing the square and the quadratic formula"
                                }, 
                                {
                                    "description": "You are familiar with factoring quadratic expressions and solving quadratic equations.  Well, as you might guess, not everything in life has to be equal.\n\nIn this short tutorial we will look at quadratic inequalities.", 
                                    "id": "quad_ineq", 
                                    "title": "Quadratic inequalities"
                                }, 
                                {
                                    "description": "\"Polynomials\" sound like a fancy word, but you just have to break down the root words.  \"Poly\" means \"many\".  So we're just talking about \"many nomials\" and everyone knows what a \"nomial\" is.  Okay, most of us don't.  Well, a polynomials has \"many\" terms. \n\nFrom understanding what a \"term\" is to basic simplification, addition and subtraction of polynomials, this tutorial will get you very familiar with the world of many \"nomials.\" :)", 
                                    "id": "polynomial_tutorial", 
                                    "title": "Adding and multiplying polynomials"
                                }, 
                                {
                                    "description": "You know what polynomials are.  You know how to add, subtract, and multiply them.  Unless you are completely incurious, you must be wondering how to divide them!\n\nIn this tutorial we'll explore how we divide polynomials--both through algebraic long division and synthetic division. (We like classic algebraic long division more since you can actually understand what you're doing.)", 
                                    "id": "dividing_polynomials", 
                                    "title": "Dividing polynomials"
                                }, 
                                {
                                    "description": "In this tutorial, we'll learn a technique for dividing one polynomial by another--synthetic division. As always, we'll also explore why it works!", 
                                    "id": "synthetic-division", 
                                    "title": "Synthetic division"
                                }, 
                                {
                                    "description": "Factoring quadratics are now second nature to you.  Even when traditional factoring is difficult, you know about completing the square and the quadratic formula.  Now you're ready for something more interesting.  Well, as you'll see in this tutorial, factoring higher degree polynomials is definitely the challenge you're looking for!", 
                                    "id": "factoring-higher-deg-polynomials", 
                                    "title": "Factoring and roots of higher degree polynomials"
                                }, 
                                {
                                    "description": "In this tutorial, we will study the behavior of polynomials and their graphs.  In particular, we'll look at which forms of a polynomial are best for determining various aspects of its graph.", 
                                    "id": "polynomial-end-behavior", 
                                    "title": "Polynomial graphs and end behavior"
                                }, 
                                {
                                    "description": "You can keep taking the powers of a binomial by hand, but, as we'll see in this tutorial, there is a much more elegant way to do it using the binomial theorem and/or Pascal's Triangle.", 
                                    "id": "binomial_theorem", 
                                    "title": "Binomial theorem"
                                }, 
                                {
                                    "description": "You get a rational expression when you divide one polynomial by another.  If you have a good understanding of factoring quadratics, you'll be able to apply this skill here to help realize where a rational expression may not be defined and how we can go about simplifying it.", 
                                    "id": "simplifying-rational-expressions", 
                                    "title": "Simplifying rational expressions"
                                }, 
                                {
                                    "description": "Have you ever wondered what would happen if you divide one polynomial by another?  What if you set that equal to something else?  Would it be as unbelievably epic as you suspect it would be?", 
                                    "id": "rational_funcs_tutorial", 
                                    "title": "Rational functions"
                                }, 
                                {
                                    "description": "", 
                                    "id": "asymptotes-graphing-rational", 
                                    "title": "Asymptotes and graphing rational functions"
                                }, 
                                {
                                    "description": "If you add several rational expressions with lower degree denominator, you are likely to get a sum with a higher degree denominator (which is the least-common multiple of the lower-degree ones).  This tutorial lets us think about going the other way--start with a rational expression with a higher degree denominator and break it up as the sum of simpler rational expressions.\n\nThis has many uses throughout mathematics.  In particular, it is key when taking inverse Laplace transforms in differential equations (which you'll take, and rock, after calculus).", 
                                    "id": "partial-fraction-expansion", 
                                    "title": "Partial fraction expansion"
                                }, 
                                {
                                    "description": "This tutorial is all about *really* being able to interpret and see meaning in algebraic expressions--including those that involve rational expressions, exponentials, and polynomials.   If you enjoy these ideas and problems, then you're really begun to develop your mathematical maturity.\n\n\n", 
                                    "id": "advanced-structure-in-expression", 
                                    "title": "Advanced structure in expressions"
                                }, 
                                {
                                    "description": "This tutorial will better connect the world of complex numbers to roots of polynomials.  It will show us that when we couldn't find roots, we just weren't looking hard enough.  In particular, the Fundamental Theorem of Algebra tells us that every non-zero polynomial in one-variable of degree n has exactly n-roots (although they might not all be real!)", 
                                    "id": "fundamental-theorem-of-algebra", 
                                    "title": "Fundamental Theorem of Algebra"
                                }
                            ], 
                            "description": "Exploring quadratics and higher degree polynomials.  Also in-depth look at rational functions.", 
                            "id": "polynomial_and_rational", 
                            "title": "Polynomial and rational functions"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "You get a rational expression when you divide one polynomial by another.  If you have a good understanding of factoring quadratics, you'll be able to apply this skill here to help realize where a rational expression may not be defined and how we can go about simplifying it.", 
                                    "id": "simplifying-rational-alg", 
                                    "title": "Simplifying rational expressions"
                                }, 
                                {
                                    "description": "Well, rational expressions are just algebraic expressions formed by dividing one expression by another. In this tutorial, we'll see that, even though they may look hairy, adding and subtracting rational expressions involves most of what we know about adding and subtracting numeric fractions.", 
                                    "id": "rational_expressions", 
                                    "title": "Adding and subtracting rational expressions"
                                }, 
                                {
                                    "description": "Rational functions are often not defined at certain points and have very interesting behavior has the input variable becomes very large in magnitude.  This tutorial explores how to graph these functions, paying attention to these special features.  We'll talk a lot about vertical and horizontal asymptotes.", 
                                    "id": "rational-function-graphing", 
                                    "title": "Graphing rational functions"
                                }, 
                                {
                                    "description": "If you add several rational expressions with lower degree denominator, you are likely to get a sum with a higher degree denominator (which is the least-common multiple of the lower-degree ones).  This tutorial lets us think about going the other way--start with a rational expression with a higher degree denominator and break it up as the sum of simpler rational expressions.", 
                                    "id": "partial-fraction-expan-alg", 
                                    "title": "Partial fraction expansion"
                                }, 
                                {
                                    "description": "The equations you are about to see are some of the hairiest in all of algebra.  The key is to keep calm and don't let the rational equation be the boss of you.", 
                                    "id": "solving-rational-equations", 
                                    "title": "Solving rational equations"
                                }, 
                                {
                                    "description": "Let's extend what we know about multiplying and dividing fractions to rational expressions.  It may look complicated, but it really is about applying some core principles of what fractions represent.", 
                                    "id": "multi-div-rational-exp", 
                                    "title": "Multiplying and dividing rational expressions"
                                }
                            ], 
                            "description": "You have probably been wondering whether our powers of algebraic problem solving break down if we divide by the variable or we have entire expressions in denominator of a fraction.  Well, they don't!   In this topic, you'll learn how to interpret and manipulate  rational expressions (when you have one algebraic expression divided by another)!", 
                            "id": "rational-expressions", 
                            "title": "Rational expressions"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "From compound interest to population growth to half lives of radioactive materials, it all comes down to exponential growth and decay.", 
                                    "id": "exp_growth_decay", 
                                    "title": "Exponential growth and decay"
                                }, 
                                {
                                    "description": "As we'll see in this tutorial, anything from compound interest to radioactive decay can be modeled with exponential functions.", 
                                    "id": "exponential-modeling", 
                                    "title": "Modeling with exponential functions"
                                }, 
                                {
                                    "description": "This tutorial shows you what a logarithmic function is.  It will then go on to show the many times in nature and science that these type of functions are useful to describe what is happening.", 
                                    "id": "log_functions", 
                                    "title": "Logarithmic functions"
                                }, 
                                {
                                    "description": "Now that you are familiar with logarithms and logarithmic functions, let's think about how to solve equations involving logarithms.", 
                                    "id": "logarithmic-equations", 
                                    "title": "Logarithmic equations"
                                }, 
                                {
                                    "description": "This tutorial introduces us to one of the derivations (from finance and continuously compounding interest) of the irrational number 'e' which is roughly 2.71...", 
                                    "id": "continuous_compounding", 
                                    "title": "Continuous compounding and e"
                                }
                            ], 
                            "description": "An look at exponential and logarithmic functions including many of their properties and graphs.", 
                            "id": "exponential_and_logarithmic_func", 
                            "title": "Exponential and logarithmic functions"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "If you understand how to take an exponent and you're looking to take your mathematical game to a new level, then you've found the right tutorial.  Put simply and confusingly, logarithms are inverse operators to exponents (just as subtraction to addition or division to multiplication).  As you'll see, taking a logarithm of something tells you what exponent you need to raise a base to to get that number.", 
                                    "id": "logarithm_basics", 
                                    "title": "Logarithm basics"
                                }, 
                                {
                                    "description": "You want to go deeper in your understanding of logarithms.  This tutorial does just that by exploring properties of logarithms that will help you manipulate them in entirely new ways (mostly falling out of exponent properties).", 
                                    "id": "logarithm_properties", 
                                    "title": "Logarithm properties"
                                }, 
                                {
                                    "description": "e is a special number that shows up throughout nature (you will appreciate this more and more as you develop your mathematical understanding).  Given this, logarithms with base e have a special name--natural logarithms.  In this tutorial, we will learn to evaluate and graph this special function.", 
                                    "id": "natural_logarithm", 
                                    "title": "Natural logarithms"
                                }, 
                                {
                                    "description": "Logarithms show up in science and music far more than you might first imagine.  This tutorial explores where these appearances occur!", 
                                    "id": "logarithmic-scale-patterns", 
                                    "title": "Logarithmic scale and patterns"
                                }
                            ], 
                            "description": "Log-a-what?  No, this tutorial is about neither chopped wood nor music (actually logarithms do have applications in music), but it is fascinating nonetheless.\n\nYou know how to take an exponent.  Now you can think about what exponent you have to raise a number to to get another number.  Yes, I agree--unstoppable fun for the whole family.  No, seriously, logarithms are used everywhere (including to measure earthquakes and sound).", 
                            "id": "logarithms-tutorial", 
                            "title": "Logarithms"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "This is where math starts to get really cool.  It may see strange to define a number whose square is negative one.  Why do we do this?  Because it fits a nice niche in the math ecosystem and can be used to solve problems in engineering and science (not to mention some of the coolest fractals are based on imaginary and complex numbers).  The more you think about it, you might realize that all numbers, not just i, are very abstract.", 
                                    "id": "imaginary_unit_i-a2", 
                                    "title": "The imaginary unit i"
                                }, 
                                {
                                    "description": "Let's start constructing numbers that have both a real and imaginary part.  We'll call them complex.  We can even plot them on the complex plane and use them to find the roots of ANY quadratic equation.  The fun must not stop!", 
                                    "id": "complex_numbers", 
                                    "title": "Complex numbers"
                                }
                            ], 
                            "description": "Understanding and solving equations with imaginary numbers.", 
                            "id": "complex-numbers-a2", 
                            "title": "Imaginary and complex numbers"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "What is a conic other than a jazz singer from New Orleans?  Well, as you'll see in this tutorial, a conic section is formed when you intersect a plane with cones.  You end up with some familiar shapes (like circles and ellipses) and some that are a bit unexpected (like hyperbolas).  This tutorial gets you set up with the basics and is a good foundation for going deeper into the world of conic sections.", 
                                    "id": "conic_section_intro", 
                                    "title": "Conic section basics"
                                }, 
                                {
                                    "description": "You've seen circles your entire life.  You've even studied them a bit in math class.  Now we go further, taking a deep look at the equations of circles.", 
                                    "id": "circles-tutorial-precalc", 
                                    "title": "Circles"
                                }, 
                                {
                                    "description": "What would you call a circle that isn't a circle?  One that is is is taller or fatter rather than being perfectly round?  An ellipse. (All circles are special cases of ellipses.)\n\nIn this tutorial we go deep into the equations and graphs of ellipses.", 
                                    "id": "ellipses-precalc", 
                                    "title": "Ellipses"
                                }, 
                                {
                                    "description": "You've seen parabolas already when you graphed quadratic functions.  Now we will look at them from a conic perspective.  In particular we will look at them as the set of all points equidistant from a point (focus) and a line (directrix).  Have fun!", 
                                    "id": "parabolas_precalc", 
                                    "title": "Parabolas"
                                }, 
                                {
                                    "description": "It is no hyperbole  to say that hyperbolas are awesome.  In this tutorial, we look closely at this wacky conic section.  We pay special attention to its graph and equation.", 
                                    "id": "hyperbolas-precalc", 
                                    "title": "Hyperbolas"
                                }, 
                                {
                                    "description": "You're familiar with the graphs and equations of all of the conic sections.  Now you want practice identifying them given only their equations.  You, my friend, are about to click on exactly the right tutorial.", 
                                    "id": "conics_precalc_eqs", 
                                    "title": "Conics from equations"
                                }, 
                                {
                                    "description": "Do you think that the math exams that you have to take are hard?  Well, if you have the stomach, try the problem(s) in this tutorial.  They are not only conceptually difficult, but they are also hairy.\n\nDon't worry if you have trouble with this.  Most of us would.  The IIT JEE is an exam administered to 200,000 students every year in India to select which 2000 go to the competitive IITs.  They need to make sure that most of the students can't do most of the problems so that they can really whittle the applicants down.", 
                                    "id": "jee_hyperbolas", 
                                    "title": "Conics in the IIT JEE"
                                }
                            ], 
                            "description": "A detailed look at shapes that are prevalent in science: conic sections", 
                            "id": "conics_precalc", 
                            "title": "Conic sections"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Keanu Reeves' virtual world in the The Matrix (I guess we can call all three movies \"The Matrices\") have more in common with this tutorial than you might suspect.  Matrices are ways of organizing numbers.  They are used extensively in computer graphics, simulations and information processing in general.  The super-intelligent artificial intelligences that created The Matrix for Keanu must have used many matrices in the process.\n\nThis tutorial introduces you to what a matrix is and how we define some basic operations on them.", 
                                    "id": "basic-matrix-operations-alg2", 
                                    "title": "Basic matrix operations"
                                }, 
                                {
                                    "description": "You know what a matrix is, how to add them and multiply them by a scalar.  Now we'll define multiplying one matrix by another matrix.  The process may seem bizarre at first (and maybe even a little longer than that), but there is a certain naturalness to the process.  When you study more advanced linear algebra and computer science, it has tons of applications (computer graphics, simulations, etc.)", 
                                    "id": "matrix-multiplication-alg2", 
                                    "title": "Matrix multiplication"
                                }
                            ], 
                            "description": "", 
                            "id": "alg2-matrices", 
                            "title": "Matrices"
                        }
                    ], 
                    "description": "Conceptual videos and worked examples from basic algebra through algebra 2. Includes videos from the former algebra worked examples playlists.", 
                    "id": "algebra2", 
                    "title": "Algebra II"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "In this tutorial, you will learn all the trigonometry that you are likely to remember in ten years (assuming you are a lazy non-curious, non-lifelong learner).  But even in that non-ideal world where you forgot everything else, you'll be able to do more than you might expect with the concentrated knowledge you are about to get.", 
                                    "id": "basic_trig_ratios", 
                                    "title": "Basic trigonometric ratios"
                                }, 
                                {
                                    "description": "In this tutorial, we will build on our understanding of similarity to get a deeper appreciation for the motivation behind trigonometric ratios and relationships.", 
                                    "id": "cc-trig-ratios-similarity", 
                                    "title": "Trigonometric ratios and similarity"
                                }, 
                                {
                                    "description": "You are now familiar with the basic trig ratios.  We'll now use them to solve a whole bunch of real-world problems.  Seriously, trig shows up a lot in the real-world.", 
                                    "id": "trig-application-problems", 
                                    "title": "Trig ratio application problems"
                                }, 
                                {
                                    "description": "You're now familiar with sine, cosine and tangent.  Now you'll see that mathematicians have also defined functions that are the reciprocal of those: cosecant, secant and cotangent.", 
                                    "id": "reciprocal-trig-functions", 
                                    "title": "Reciprocal trig functions"
                                }
                            ], 
                            "description": "", 
                            "id": "basic-trigonometry", 
                            "title": "Basic trigonometry"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Most people know that you can measure angles with degrees, but only exceptionally worldly people know that radians can be an exciting alternative.  As you'll see, degrees are somewhat arbitrary (if we lived on a planet that took 600 days to orbit its star, we'd probably have 600 degrees in a full revolution).  Radians are pure.  Seriously, they are measuring the angle in terms of how long the arc that subtends them is (measured in radiuseseses).  If that makes no sense, imagine measuring a bridge with car lengths.  If that still doesn't make sense, watch this tutorial!", 
                                    "id": "radians_tutorial", 
                                    "title": "Radians"
                                }, 
                                {
                                    "description": "", 
                                    "id": "Trig-unit-circle", 
                                    "title": "Trig problems on the unit circle"
                                }, 
                                {
                                    "description": "In this tutorial, we'll really digest how special triangles and angles that show up a lot in mathematics relate to each other and the various trig functions.", 
                                    "id": "trig-functions-special-angles", 
                                    "title": "Trig functions of special angles"
                                }, 
                                {
                                    "description": "Someone has taken the sine of an angle and got 0.85671 and they won't tell you what the angle is!!!  You must know it!  But how?!!!\n\nInverse trig functions are here to save your day (they often go under the aliases arcsin, arccos, and arctan).", 
                                    "id": "inverse_trig_functions", 
                                    "title": "Inverse trig functions"
                                }
                            ], 
                            "description": "Let's now extend the domain of the trig function we love by exploring the unit circle definition of trig functions!", 
                            "id": "unit-circle-trig-func", 
                            "title": "Unit circle definition of trig functions"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "The unit circle definition allows us to define sine and cosine over all real numbers.  Doesn't that make you curious what the graphs might look like?  Well this tutorial will scratch that itch (and maybe a few others).  Have fun.", 
                                    "id": "trig_graphs_tutorial", 
                                    "title": "Graphs of trig functions"
                                }, 
                                {
                                    "description": "By now, you are reasonably familiar with the graphs of sine and cosine and are beginning to appreciate that they can be used to model periodic phenomena.  In this tutorial, you'll get experience doing just that--modeling with periodic functions!", 
                                    "id": "modeling-periodic-functions", 
                                    "title": "Modeling with periodic functions"
                                }, 
                                {
                                    "description": "Pi (3.14159...) seems to get all of the attention in mathematics.  On some level this is warranted.  The ratio of the circumference of a circle to the diameter.  Seems pretty pure.  But what about the ratio of the circumference to the radius (which is two times pi and referred to as \"tau\")?  Now that you know a bit of trigonometry, you'll discover in videos made by Sal and Vi that \"tau\" may be much more deserving of the throne!", 
                                    "id": "long_live_tau", 
                                    "title": "Long live tau"
                                }
                            ], 
                            "description": "In this topic, we'll gain a deeper appreciation for the periodic nature of trig functions by visualizing and modeling real-world phenomena with them.", 
                            "id": "trig-function-graphs", 
                            "title": "Graphs of trig functions"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "In this tutorial, we will explore the unit circle in more depth so that we can better appreciate how trig functions of an angle might relate to angles that are in some way symmetric within the unit circle.  We'll also look at the periodicity of the functions themselves (why they repeat after a certain change in angle).", 
                                    "id": "trig-symmetry-periodicity", 
                                    "title": "Symmetry and periodicity of trig functions"
                                }, 
                                {
                                    "description": "In this tutorial, we look at the relationship between the definitions of sine, cosine and tangent (both SOH CAH TOA and unit circle definitions) and the Pythagorean theorem to derive and apply the Pythagorean identity.  This is the building block of much of the rest of the trigonometric identities and will be surprisingly useful the rest of your life!", 
                                    "id": "pythagorean-identity", 
                                    "title": "Pythagorean identity"
                                }, 
                                {
                                    "description": "We'll now see that we can express the sin(a+b)  and the cos(a+b) in terms of sin a, sin b, cos a, and cos b.  This will be handy in a whole set of applications.", 
                                    "id": "angle-addition-formulas-trig", 
                                    "title": "Angle addition formulas"
                                }, 
                                {
                                    "description": "Let's see if we can prove the angle addition formulas for sine and cosine!", 
                                    "id": "angle-addition-formula-proofs", 
                                    "title": "Angle addition formula proofs"
                                }, 
                                {
                                    "description": "The primary tool that we've had to find the length of a side of a triangle given the other two sides has been the Pythagorean theorem, but that only applies to right triangles.  In this tutorial, we'll extend this triangle-side-length toolkit with the law of cosines and the law of sines.  Using these tool, given information about side lengths and angles, we can figure out things about even non-right triangles that you may have thought weren't even possible!", 
                                    "id": "law-sines-cosines", 
                                    "title": "Law of cosines and law of sines"
                                }, 
                                {
                                    "description": "If you're starting to sense that there may be more to trig functions than meet the eye, you are sensing right.  In this tutorial you'll discover exciting and beautiful and elegant and hilarious relationships between our favorite trig functions (and maybe a few that we don't particularly like).\n\nWarning: Many of these videos are the old, rougher Sal with the cheap equipment!", 
                                    "id": "trig_iden_tutorial", 
                                    "title": "Trigonometric identities"
                                }, 
                                {
                                    "description": "This tutorial is a catch-all for a bunch of things that we haven't been able (for lack of time or ability) to categorize into other tutorials :(", 
                                    "id": "more-trig-examples", 
                                    "title": "Advanced trig examples"
                                }
                            ], 
                            "description": "", 
                            "id": "less-basic-trigonometry", 
                            "title": "Trig identities and examples"
                        }
                    ], 
                    "description": "Videos and exercises on trigonometry.  Watch the \"Geometry\" playlist first if you have trouble understanding the topics covered here.", 
                    "id": "trigonometry", 
                    "title": "Trigonometry"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "Can I pick a red frog out of a bag that only contains marbles?  Is it smart to buy a lottery ticket?\n\nEven if we are unsure about whether something will happen, can we start to be mathematical about the \"chances\" of an event (essentially realizing that some things are more likely than others).  This tutorial will introduce us to the tools that allow us to think about random events.", 
                                    "id": "basic_probability", 
                                    "title": "Basic probability"
                                }, 
                                {
                                    "description": "What is the probability of getting a diamond or an ace from a deck of cards?  Well I could get a diamond that is not an ace, an ace that is not a diamond, or the ace of diamonds.  This tutorial helps us think these types of situations through a bit better (especially with the help of our good friend, the Venn diagram).", 
                                    "id": "addition_rule_probability", 
                                    "title": "Venn diagrams and adding probabilities"
                                }, 
                                {
                                    "description": "What is the probability of making three free throws in a row (LeBron literally asks this in this tutorial).\n\nIn this tutorial, we'll explore compound events happening where the probability of one event is not dependent on the outcome of another (compound, independent, events).", 
                                    "id": "independent_events", 
                                    "title": "Compound, independent events"
                                }, 
                                {
                                    "description": "What's the probability of picking two \"e\" from the bag in scrabble (assuming that I don't replace the tiles).  Well, the probability of picking an 'e' on your second try depends on what happened in the first (if you picked an 'e' the first time around, then there is one less 'e' in the bag).  This is just one of many, many type of scenarios involving dependent probability.", 
                                    "id": "dependent_probability", 
                                    "title": "Dependent probability"
                                }, 
                                {
                                    "description": "Whether you are learning computer science, logic, or probability (or a bunch of other things), it can be very, very useful to have this \"set\" of skills.  From what a set is to how we can operate on them, this tutorial will have you familiar with the basics of sets!", 
                                    "id": "basic_set_operations", 
                                    "title": "Basic set operations"
                                }, 
                                {
                                    "description": "Sal's old videos on probability.  Covered better in other tutorials but here because some people actually like these better.", 
                                    "id": "old_prob_videos", 
                                    "title": "Old school probability (very optional)"
                                }
                            ], 
                            "description": "Introduction to probability.  Independent and dependent events.  Compound events.  Mutual exclusive events.  Addition rule for probability.", 
                            "id": "independent-dependent-probability", 
                            "title": "Independent and dependent events"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "You want to display your Chuck Norris dolls on your desk at school and there is only room for five of them.  Unfortunately, you own 50.  How many ways can you pick the dolls and arrange them on your desk?  What if you don't care what order they are in or how they are posed (okay, of course you care about their awesome poses)?", 
                                    "id": "permutations_and_combinations", 
                                    "title": "Permutations and combinations"
                                }, 
                                {
                                    "description": "This tutorial will apply the permutation and combination tools you learned in the last tutorial to problems of probability.  You'll finally learn that there may be better \"investments\" than poring all your money into the Powerball Lottery.", 
                                    "id": "probability_combinatorics", 
                                    "title": "Probability using combinatorics"
                                }, 
                                {
                                    "description": "", 
                                    "id": "decisions-with-probability", 
                                    "title": "Making decisions with probability"
                                }
                            ], 
                            "description": "Permutations and combinations.  Using combinatorics to solve questions in probability.", 
                            "id": "probability-and-combinatorics-topic", 
                            "title": "Probability and combinatorics"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "types-of-studies", 
                                    "title": "Types of statistical studies"
                                }, 
                                {
                                    "description": "", 
                                    "id": "hypothesis-test", 
                                    "title": "Hypothesis testing"
                                }, 
                                {
                                    "description": "", 
                                    "id": "categorical-data", 
                                    "title": "Categorical data"
                                }
                            ], 
                            "description": "", 
                            "id": "statistical-studies", 
                            "title": "Statistical studies"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "This is the foundational tutorial for the rest of statistics.  We start thinking about how you can represent a set of numbers with one number that somehow represents the \"center\".  We then talk about the differences between populations, samples, parameters and statistics.", 
                                    "id": "central_tendency", 
                                    "title": "Measures of central tendency"
                                }, 
                                {
                                    "description": "Whether you're looking at scientific data or stock price charts, box-and-whisker plots can show up in your life.  This tutorial covers what they are, how to read them and how to construct them.  We'd consider this tutorial very optional, but it is a good application of dealing with medians and ranges.", 
                                    "id": "Box-and-whisker plots", 
                                    "title": "Box-and-whisker plots"
                                }, 
                                {
                                    "description": "We have tools (like the arithmetic mean) to measure central tendency and are now curious about representing how much the data in a set varies from that central tendency.  In this tutorial we introduce the variance and standard deviation (which is just the square root of the variance) as two commonly used tools for doing this.", 
                                    "id": "variance_std_deviation", 
                                    "title": "Variance and standard deviation"
                                }, 
                                {
                                    "description": "This tutorial covers central tendency and dispersion.  It is redundant with the other tutorials on this topic, but it has the benefit of messy handwriting and a cheap microphone. This is Sal circa 2007 so take it all with a grain of salt (or just skip it altogether).", 
                                    "id": "old-stats-videos", 
                                    "title": "Sal's old statistics videos"
                                }
                            ], 
                            "description": "Measures of central tendency and dispersion.  Mean, median, mode, variance, and standard deviation.", 
                            "id": "descriptive-statistics", 
                            "title": "Descriptive statistics"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "random_variables_prob_dist", 
                                    "title": "Random variables and probability distributions"
                                }, 
                                {
                                    "description": "Now that we know what a random variable is, we can think about expected value.  As we'll see, it can be viewed as a probability-weighted average of possible outcomes!", 
                                    "id": "expected-value", 
                                    "title": "Expected value"
                                }, 
                                {
                                    "description": "", 
                                    "id": "binomial_distribution", 
                                    "title": "Binomial distribution"
                                }, 
                                {
                                    "description": "", 
                                    "id": "poisson_process", 
                                    "title": "Poisson process"
                                }
                            ], 
                            "description": "Random variables.  Expected value.  Probability distributions (both discrete and continuous).  Binomial distribution.  Poisson processes.", 
                            "id": "random-variables-topic", 
                            "title": "Random variables and probability distributions"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Even when there might be a rough linear relationship between two variables, the data in the real-world is never as clean as you want it to be.  This tutorial helps you think about how you can best fit a line to the relationship between two variables.", 
                                    "id": "regression-correlation", 
                                    "title": "Linear regression and correlation"
                                }
                            ], 
                            "description": "Fitting a line to points.  Linear regression.  R-squared.", 
                            "id": "regression", 
                            "title": "Regression"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "The normal distribution (often referred to as the \"bell curve\" is at the core of most of inferential statistics.  By assuming that most complex processes result in a normal distribution (we'll see why this is reasonable), we can gauge the probability of it happening by chance.\n\nTo best enjoy this tutorial, it is good to come to it understanding what probability distributions and random variables are.  You should also be very familiar with the notions of population and sample mean and standard deviation.", 
                                    "id": "normal_distribution", 
                                    "title": "Normal distribution"
                                }, 
                                {
                                    "description": "In this tutorial, we experience one of the most exciting ideas in statistics--the central limit theorem.  Without it, it would be a lot harder to make any inferences about population parameters given sample statistics.  It tells us that, regardless of what the population distribution looks like, the  distribution of the sample means (you'll learn what that is) can be normal.\n\nGood idea to understand a bit about normal distributions before diving into this tutorial.", 
                                    "id": "sampling_distribution", 
                                    "title": "Sampling distribution"
                                }, 
                                {
                                    "description": "We all have confidence intervals (\"I'm the king of the world!!!!\") and non-confidence intervals (\"No one loves me\").  That is not what this tutorial is about.\n\nThis tutorial takes what you already know about the central limit theorem, sampling distributions, and z-scores and uses these tools to dive into the world of inferential statistics.  It may seem magical at first, but from our sample, we can now make inferences about the probability of our population mean actually being in an interval.", 
                                    "id": "confidence-intervals", 
                                    "title": "Confidence intervals"
                                }, 
                                {
                                    "description": "Ever wondered what pollsters are talking about when they said that there is a 3% \"margin of error\" in their results.  Well, this tutorial will not only explain what it means, but give you the tools and understanding to be a pollster yourself!", 
                                    "id": "margin-of-error", 
                                    "title": "Bernoulli distributions and margin of error"
                                }, 
                                {
                                    "description": "This tutorial helps us answer one of the most important questions not only in statistics, but all of science:  how confident are we that a result from a new drug or process is not due to random chance but due to an actual impact.\n\nIf you are familiar with sampling distributions and confidence intervals, you're ready for this adventure!", 
                                    "id": "hypothesis-testing", 
                                    "title": "Hypothesis testing with one sample"
                                }, 
                                {
                                    "description": "You're already familiar with hypothesis testing with one sample.  In this tutorial, we'll go further by testing whether the difference between the means of two samples seems to be unlikely purely due to chance.", 
                                    "id": "hypothesis-testing-two-samples", 
                                    "title": "Hypothesis testing with two samples"
                                }, 
                                {
                                    "description": "You've gotten good at hypothesis testing when you can make assumptions about the underlying distributions.  In this tutorial, we'll learn about a new distribution (the chi-square one) and how it can help you (yes, you) infer what an underlying distribution even is!", 
                                    "id": "chi-square", 
                                    "title": "Chi-square probability distribution"
                                }, 
                                {
                                    "description": "You already know a good bit about hypothesis testing with one or two samples.  Now we take things further by making inferences based on three or more samples.  We'll use the very special F-distribution to do it (F stands for \"fabulous\").", 
                                    "id": "anova", 
                                    "title": "Analysis of variance"
                                }
                            ], 
                            "description": "Making inferences based on sample data.  Confidence intervals.  Margin of error.  Hypothesis testing.", 
                            "id": "statistics-inferential", 
                            "title": "Inferential statistics"
                        }
                    ], 
                    "description": "", 
                    "id": "probability", 
                    "title": "Probability and statistics"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "vector-basic", 
                                    "title": "Vector basics"
                                }, 
                                {
                                    "description": "", 
                                    "id": "rect-form", 
                                    "title": "Vectors in rectangular form"
                                }, 
                                {
                                    "description": "", 
                                    "id": "magnitude-direction", 
                                    "title": "Vectors in magnitude and direction form"
                                }
                            ], 
                            "description": "", 
                            "id": "vectors-precalc", 
                            "title": "Vectors"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Keanu Reeves' virtual world in the The Matrix (I guess we can call all three movies \"The Matrices\") have more in common with this tutorial than you might suspect.  Matrices are ways of organizing numbers.  They are used extensively in computer graphics, simulations and information processing in general.  The super-intelligent artificial intelligences that created The Matrix for Keanu must have used many matrices in the process.\n\nThis tutorial introduces you to what a matrix is and how we define some basic operations on them.", 
                                    "id": "Basic_matrix_operations", 
                                    "title": "Basic matrix operations"
                                }, 
                                {
                                    "description": "You know what a matrix is, how to add them and multiply them by a scalar.  Now we'll define multiplying one matrix by another matrix.  The process may seem bizarre at first (and maybe even a little longer than that), but there is a certain naturalness to the process.  When you study more advanced linear algebra and computer science, it has tons of applications (computer graphics, simulations, etc.)", 
                                    "id": "matrix_multiplication", 
                                    "title": "Matrix multiplication"
                                }, 
                                {
                                    "description": "As we'll see, some of the properties of scalar multiplication (like the distributive and associative properties) have analogs in matrix multiplication while some don't (the commutative property). ", 
                                    "id": "properties-matrix-multiplication", 
                                    "title": "Properties of matrix multiplication"
                                }, 
                                {
                                    "description": "In arithmetic, we learned than a number times 1 is still that number and that anything times 0 is 0.  In this tutorial, we attempt to extend these ideas to the world of matrices!", 
                                    "id": "zero-identity-matrix-tutorial", 
                                    "title": "Zero and identity matrices"
                                }, 
                                {
                                    "description": "We'll now see one of the most powerful applications of matrix multiplication--geometric transformations.  This is core of what videos games and computer-based animation uses to \"transform\" figures based on movement or perspective.  You probably never thought matrices could be so much fun!", 
                                    "id": "transformation-matrix", 
                                    "title": "Geometric transformations with matrices"
                                }, 
                                {
                                    "description": "Multiplying by the inverse of a matrix is the closest thing we have to matrix division.  Like multiplying a regular number by its reciprocal to get 1, multiplying a matrix by its inverse gives us the identity matrix (1 could be thought of as the \"identity scalar\").\n\nThis tutorial will walk you through this sometimes involved process which will become bizarrely fun once you get the hang of it.", 
                                    "id": "inverting_matrices", 
                                    "title": "Inverting matrices"
                                }, 
                                {
                                    "description": "", 
                                    "id": "matrix-equations", 
                                    "title": "Matrix equations"
                                }, 
                                {
                                    "description": "You've probably already appreciated that there are many ways to solve a system of equations.  Well, we'll introduce you to another one in this tutorial.  Reduced row echelon form has us performing operations on matrices to get them in a form that helps us solve the system.", 
                                    "id": "reduced_row_echelon", 
                                    "title": "Reduced row echelon form"
                                }
                            ], 
                            "description": "Understanding and solving matrices.", 
                            "id": "precalc-matrices", 
                            "title": "Matrices"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Here we will explore representing our x's and y's in terms of a third variable or parameter (often 't').  Not only can we describe new things, but it can be super useful for describing things like particle motion in physics.", 
                                    "id": "parametric", 
                                    "title": "Parametric equations"
                                }, 
                                {
                                    "description": "Feel that Cartesian coordinates are too \"square\".  That they bias us towards lines and away from cool spirally things.  Well polar coordinates be just what you need!", 
                                    "id": "polar_coor", 
                                    "title": "Polar coordinates"
                                }
                            ], 
                            "description": "An alternative to Cartesian coordinates.", 
                            "id": "parametric_equations", 
                            "title": "Parametric equations and polar coordinates"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "This is where math starts to get really cool.  It may see strange to define a number whose square is negative one.  Why do we do this?  Because it fits a nice niche in the math ecosystem and can be used to solve problems in engineering and science (not to mention some of the coolest fractals are based on imaginary and complex numbers).  The more you think about it, you might realize that all numbers, not just i, are very abstract.", 
                                    "id": "i_precalc", 
                                    "title": "The imaginary unit i"
                                }, 
                                {
                                    "description": "Let's start constructing numbers that have both a real and imaginary part.  We'll call them complex.  We can even plot them on the complex plane and use them to find the roots of ANY quadratic equation.  The fun must not stop!", 
                                    "id": "complex_num_precalc", 
                                    "title": "Complex number introduction"
                                }, 
                                {
                                    "description": "", 
                                    "id": "factoring-with-complex-numbers", 
                                    "title": "Factoring using imaginary numbers"
                                }, 
                                {
                                    "description": "", 
                                    "id": "multiplying-dividing-complex", 
                                    "title": "Multiplying and dividing complex numbers"
                                }, 
                                {
                                    "description": "You know what imaginary and complex numbers are, but want to start digging a bit deeper.  In this tutorial, we will explore different ways of representing a complex number and mapping them on the complex plane.", 
                                    "id": "complex_analysis", 
                                    "title": "The complex plane"
                                }, 
                                {
                                    "description": "", 
                                    "id": "exponential-form-complex-numbers", 
                                    "title": "Exponential form of complex numbers"
                                }, 
                                {
                                    "description": "This tutorial goes through a fancy problem from the IIT JEE exam in India (competitive exam for getting into their top engineering schools).  Whether or not you live in India, this is a good example to test whether you are a complex number rock star.", 
                                    "id": "complex_number_challenge", 
                                    "title": "Challenging complex number problems"
                                }
                            ], 
                            "description": "Understanding i and the complex plane", 
                            "id": "imaginary_complex_precalc", 
                            "title": "Imaginary and complex numbers"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "basic_prob_precalc", 
                                    "title": "Basic probability"
                                }, 
                                {
                                    "description": "What is the probability of making three free throws in a row (LeBron literally asks this in this tutorial).\n\nIn this tutorial, we'll explore compound events happening where the probability of one event is not dependent on the outcome of another (compound, independent, events).", 
                                    "id": "independent_events_precalc", 
                                    "title": "Compound, independent events"
                                }, 
                                {
                                    "description": "What's the probability of picking two \"e\" from the bag in scrabble (assuming that I don't replace the tiles).  Well, the probability of picking an 'e' on your second try depends on what happened in the first (if you picked an 'e' the first time around, then there is one less 'e' in the bag).  This is just one of many, many type of scenarios involving dependent probability.", 
                                    "id": "dependent_events_precalc", 
                                    "title": "Dependent events"
                                }, 
                                {
                                    "description": "You want to display your Chuck Norris dolls on your desk at school and there is only room for five of them.  Unfortunately, you own 50.  How many ways can you pick the dolls and arrange them on your desk?  What if you don't what order they are in or how they are posed (okay, of course you care about their awesome poses)?", 
                                    "id": "combinatorics_precalc", 
                                    "title": "Permutations and combinations"
                                }, 
                                {
                                    "description": "This tutorial will apply the permutation and combination tools you learned in the last tutorial to problems of probability.  You'll finally learn that there may be better \"investments\" than poring all your money into the Powerball Lottery.", 
                                    "id": "prob_combinatorics_precalc", 
                                    "title": "Probability using combinatorics"
                                }
                            ], 
                            "description": "Basics of probability and combinatorics", 
                            "id": "prob_comb", 
                            "title": "Probability and combinatorics"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Proof by induction is a core tool.  This tutorial walks you through the general idea that if 1) something is true for a base case (say when n=1) and 2) if it is true for n, then it is also true for n+1, then it must be true for all n!  Amazing!", 
                                    "id": "proof_by_induction", 
                                    "title": "Induction"
                                }, 
                                {
                                    "description": "This sequence (pun intended) of videos and exercises  will help us explore ordered lists of objects--even infinite ones--that often have some pattern to them.  We will then explore constructing sequences where the nth term is the sum of the first n terms of another sequence (series).  This is surprisingly useful in a whole series (pun intended) of applications from finance to drug dosage.", 
                                    "id": "seq_and_series", 
                                    "title": "Basic sequences and series"
                                }, 
                                {
                                    "description": "What happens when the ratio between successive terms in a sequence is the same (or it has a \"common ratio\")?  Well, then we'd be dealing with a geometric sequence (which comes up extremely frequently in mathematics).", 
                                    "id": "precalc-geometric-sequences", 
                                    "title": "Geometric sequences"
                                }, 
                                {
                                    "description": "Whether you are computing mortgage payments or calculating how many users your website will have after a few years,  geometric  series show up in life far more than you imagine.  This tutorial will review all the important concepts and more!", 
                                    "id": "geometric-sequence-series", 
                                    "title": "Finite geometric series"
                                }, 
                                {
                                    "description": "You're already familiar with finite geometric series, but you don't want the summation to stop!!  What happens if you keep adding?  The terms are getting small fast!  Can it be that the sum of an infinite number of rapidly shrinking terms can be finite!  Yes, often times it can!  Mind-blowing!  Stupendous!", 
                                    "id": "infinite-geometric-series", 
                                    "title": "Infinite geometric series"
                                }, 
                                {
                                    "description": "You understand what sequences and series are and the mathematical notation for them.  This tutorial takes things further by exploring ideas of convergence divergence and other, more challenging topics.", 
                                    "id": "advanced-sequences-series", 
                                    "title": "Advanced sequences and series"
                                }, 
                                {
                                    "description": "You will hear the words \"deductive reasoning\" and \"inductive reasoning\" throughout your life.  This very optional tutorial will give you context for what these mean.", 
                                    "id": "deductive-and-inductive-reasoning", 
                                    "title": "Deductive and inductive reasoning"
                                }, 
                                {
                                    "description": "In this tutorial, we'll see that we can often define a function in terms of itself!  This may seem circular and illogical at first, but, as we'll see, it is actually quite reasonable and useful!", 
                                    "id": "recursive-functions", 
                                    "title": "Recursive functions"
                                }
                            ], 
                            "description": "An assortment of concepts in math that help us deal with sequences and proofs.", 
                            "id": "seq_induction", 
                            "title": "Sequences, series and induction"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "You know your regular trig functions that are defined with the help of the unit circle.  We will now define a new class of functions constructed from exponentials that have an eery resemblance to those classic trig functions (but are still quite different).", 
                                    "id": "hyperbolic_trig_intro", 
                                    "title": "Intro to hyperbolic functions"
                                }
                            ], 
                            "description": "Motivation and understanding of hyperbolic functions.", 
                            "id": "hyperbolic_trig_topic", 
                            "title": "Hyperbolic functions"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Limits are the core tool that we build upon for calculus.  Many times, a function can be undefined at a point, but we can think about what the function \"approaches\" as it gets closer and closer to that point (this is the \"limit\").  Other times, the function may be defined at a point, but it may approach a different limit.  There are many, many times where the function value is the same as the limit at a point.  Either way, this is a powerful tool as we start thinking about slope of a tangent line to a curve.\n\nIf you have a decent background in algebra (graphing and functions in particular), you'll hopefully enjoy this tutorial!", 
                                    "id": "limits_precalc", 
                                    "title": "Limit basics"
                                }
                            ], 
                            "description": "Preview of the calculus topic of limits", 
                            "id": "limit_topic_precalc", 
                            "title": "Limits"
                        }
                    ], 
                    "description": "", 
                    "id": "precalculus", 
                    "title": "Precalculus"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "Limits are the core tool that we build upon for calculus.  Many times, a function can be undefined at a point, but we can think about what the function \"approaches\" as it gets closer and closer to that point (this is the \"limit\").  Other times, the function may be defined at a point, but it may approach a different limit.  There are many, many times where the function value is the same as the limit at a point.  Either way, this is a powerful tool as we start thinking about slope of a tangent line to a curve.\n\nIf you have a decent background in algebra (graphing and functions in particular), you'll hopefully enjoy this tutorial!", 
                                    "id": "limits_tutorial", 
                                    "title": "Limits"
                                }, 
                                {
                                    "description": "In this tutorial, we will build our ability to visualize limits by estimating them based on graphs of functions.  We will look at both one-sided and two-sided limits.", 
                                    "id": "calculus-estimating-limits-graph", 
                                    "title": "Estimating limits from graphs"
                                }, 
                                {
                                    "description": "We often attempt to find the limit at a point where the function itself is not defined.  In this tutorial, we will use algebra to \"simplify\" functions into ones where it is defined.  Given that the original function and the simplified one may be  identical except for the limit point in question, this is a useful way of finding limits. ", 
                                    "id": "algebraic-limits", 
                                    "title": "Finding limits algebraically"
                                }, 
                                {
                                    "description": "A function isn't continuous when there is a \"break\" in its graph.  This tutorial uses limits to define this idea more formally and gives practice thinking about continuity (and discontinuity) in terms of limits.", 
                                    "id": "continuity-limits", 
                                    "title": "Continuity using limits"
                                }, 
                                {
                                    "description": "You have a basic understanding of what a limit is.  Now, in this tutorial, we can explore situation where we take the limit as x approaches negative or positive infinity (and situations where the limit itself could be unbounded).", 
                                    "id": "limits-infinity", 
                                    "title": "Limits and infinity"
                                }, 
                                {
                                    "description": "If a function is always smaller than one function and always greater than another (i.e. it is always between them), then if the upper and lower function converge to a limit at a point, then so does the one in between.  Not only is this useful for proving certain tricky limits (we use it to prove lim (x \u2192 0) of (sin x)/x, but it is a useful metaphor to use in life (seriously). :)\n\nThis tutorial is useful but optional.  It is covered in most calculus courses, but it is not necessary to progress on to the \"Introduction to derivatives\" tutorial.", 
                                    "id": "squeeze_theorem", 
                                    "title": "Squeeze theorem"
                                }, 
                                {
                                    "description": "This tutorial introduces a \"formal\" definition of limits.  So put on your ball gown and/or tuxedo to party with Mr. Epsilon Delta (no, this is not referring to a fraternity).\n\nThis tends to be covered early in a traditional calculus class (right after basic limits), but we have mixed feelings about that.  It is cool and rigorous, but also very \"mathy\" (as most rigorous things are).  Don't fret if you have trouble with it the first time.  If you have a basic conceptual understanding of what limits are (from the \"Limits\" tutorial), you're ready to start thinking about taking derivatives.", 
                                    "id": "epsilon_delta", 
                                    "title": "Epsilon delta definition of limits"
                                }
                            ], 
                            "description": "Limit introduction, squeeze theorem, and epsilon-delta definition of limits", 
                            "id": "limits_topic", 
                            "title": "Limits"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "The topic that is now known as \"calculus\" was really called \"the calculus of differentials\" when first devised by Newton (and Leibniz) roughly four hundred years ago.  To Newton, differentials were infinitely small \"changes\" in numbers that previous mathematics didn't know what to do with.  Think this has no relevence to you?  Well how would you figure out how fast something is going *right* at this moment (you'd have to figure out the very, very small change in distance over an infinitely small change in time)?  This tutorial gives a gentle introduction to the world of Newton and Leibniz.", 
                                    "id": "intro_differential_calc", 
                                    "title": "Introduction to differential calculus"
                                }, 
                                {
                                    "description": "The idea of slope is fairly straightforward-- (change in vertical) over (change in horizontal).  But how do we measure this if the (change in horizontal) is zero (which would be the case when finding the slope of the tangent line.  In this tutorial, we'll approximate this by finding the slopes of secant lines.", 
                                    "id": "secant-line-slope-tangent", 
                                    "title": "Using secant line slopes to approximate tangent slope"
                                }, 
                                {
                                    "description": "Discover what magic we can derive when we take a derivative, which is the slope of the tangent line at any point on a curve.", 
                                    "id": "derivative_intro", 
                                    "title": "Introduction to derivatives"
                                }, 
                                {
                                    "description": "You understand that a derivative can be viewed as the slope of the tangent line at a point or the instantaneous rate of change of a function with respect to x.  This tutorial will deepen your ability to visualize and conceptualize derivatives through videos and exercises.\n\nWe think you'll find this tutorial incredibly fun and satisfying (seriously).", 
                                    "id": "visualizing-derivatives-tutorial", 
                                    "title": "Visualizing graphs of functions and their derivatives"
                                }, 
                                {
                                    "description": "Let's now get a better understanding of the different derivative-related notations and use them to better understand properties of derivatives.", 
                                    "id": "derivative-properties", 
                                    "title": "Derivative properties and intuition"
                                }, 
                                {
                                    "description": "Calculus is about to seem strangely straight forward.  You've spent some time using the definition of a derivative to find the slope at a point.  In this tutorial, we'll derive and apply the derivative for any term in a polynomial.\n\nBy the end of this tutorial, you'll have the power to take the derivative of any polynomial like it's second nature!", 
                                    "id": "power_rule_tutorial", 
                                    "title": "Power rule"
                                }, 
                                {
                                    "description": "You can take the derivatives of f(x) and g(x), but what about f(g(x)) or g(f(x))?  The chain rule gives us this ability.  Because most complex and hairy functions can be thought of the composition of several simpler ones (ones that you can find derivatives of), you'll be able to take the derivative of almost any function after this tutorial.  Just imagine.", 
                                    "id": "chain_rule", 
                                    "title": "Chain rule"
                                }, 
                                {
                                    "description": "You can figure out the derivative of f(x).  You're also good for g(x).  But what about f(x) times g(x)?  This is what the product rule is all about. \n\nThis tutorial is all about the product rule.  It also covers the quotient rule (which really is just a special case of the product rule).", 
                                    "id": "product_rule", 
                                    "title": "Product and quotient rules"
                                }, 
                                {
                                    "description": "Like people, mathematical relations are not always explicit about their intentions.  In this tutorial, we'll be able to take the derivative of one variable with respect to another even when they are implicitly defined (like \"x^2 + y^2 = 1\").", 
                                    "id": "implicit_differentiation", 
                                    "title": "Implicit differentiation"
                                }, 
                                {
                                    "description": "In this tutorial we explore a common method to find the derivatives of inverse tangent (arctangent), inverse sine (arcsine), inverse cosine (arccosine) and the natural logarithm function.  ", 
                                    "id": "derivatives-inverse-functions", 
                                    "title": "Derivatives of inverse functions"
                                }, 
                                {
                                    "description": "We told you about the derivatives of many functions, but you might want proof that what we told you is actually true.  That's what this tutorial tries to do!", 
                                    "id": "der_common_functions", 
                                    "title": "Proofs of derivatives of common functions"
                                }
                            ], 
                            "description": "Calculating derivatives. Power rule. Product and quotient rules.  Chain Rule.  Implicit differentiation.  Derivatives of common functions.", 
                            "id": "taking-derivatives", 
                            "title": "Taking derivatives"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "A derivative at a point in a curve can be viewed as the slope of the line tangent to that curve at that point.  Given this, the natural next question is what the equation of that tangent line is.  In this tutorial, we'll not only find equations of tangent lines, but normal ones as well!", 
                                    "id": "normal-tangent-line-eq", 
                                    "title": "Equations of normal and tangent lines"
                                }, 
                                {
                                    "description": "Derivatives can be used to calculate instantaneous rates of change.  The rate of change of position with respect to time is velocity and the rate of change of velocity with respect to time is acceleration.  Using these ideas, we'll be able to analyze one-dimensional particle movement given position as a function of time.", 
                                    "id": "motion-along-line-derivatives", 
                                    "title": "Motion along a line"
                                }, 
                                {
                                    "description": "Can calculus be used to figure out when a function takes on a local or global maximum value?  Absolutely.  Not only that, but derivatives and second derivatives can also help us understand the shape of the function (whether they are concave upward or downward).\n\nIf you have a basic conceptual understanding of derivatives, then you can start applying that knowledge here to identify critical points, extrema, inflections points and even to graph functions.", 
                                    "id": "critical_points_graphing", 
                                    "title": "Critical points and graphing with calculus"
                                }, 
                                {
                                    "description": "", 
                                    "id": "absolute-relative-maxima-minima", 
                                    "title": "Absolute and relative maxima and minima"
                                }, 
                                {
                                    "description": "", 
                                    "id": "concavity-inflection-points", 
                                    "title": "Concavity and inflection points"
                                }, 
                                {
                                    "description": "Using calculus to solve optimization problems", 
                                    "id": "calc_optimization", 
                                    "title": "Optimization with calculus"
                                }, 
                                {
                                    "description": "The idea of a derivative being the instantaneous rate of change is useful when studying or thinking about phenomena in a whole range of fields.  In this tutorial, we begin to just scratch the surface as we apply derivatives in fields as disperse as biology and economics.", 
                                    "id": "differentiation-application", 
                                    "title": "Applying differentiation in different fields"
                                }, 
                                {
                                    "description": "Have you ever wondered how fast the area of a ripple of a pond is increasing based on how fast the ripple is?  What about how fast a volcano's volume is increasing?  This tutorial on related rates will satiate your curiosity and then some!\n\n\nSolving related rates problems using calculus", 
                                    "id": "rates_of_change", 
                                    "title": "Related rates"
                                }, 
                                {
                                    "description": "If over the last hour on the highway, you averaged 60 miles per hour, then you must have been going exactly 60 miles per hour at some point.  This is the gist of the mean value theorem (which generalizes the idea for any continuous, differentiable function).", 
                                    "id": "mean_value_theorem", 
                                    "title": "Mean value theorem"
                                }, 
                                {
                                    "description": "Limits have done their part helping to find derivatives.  Now, under the guidance of l'H\u00f4pital's rule, derivatives are looking to show their gratitude by helping to find limits.  Ever try to evaluate a function at a point and get 0/0 or infinity/infinity?  Well, that's a big clue that l'Hopital's rule can help you find the limit of the function at that point.", 
                                    "id": "lhopital_rule", 
                                    "title": "L'H\u00f4pital's rule"
                                }, 
                                {
                                    "description": "Let's see how we can local linearization can be used to approximate values of functions near values that we know.  ", 
                                    "id": "local-linearization", 
                                    "title": "Local linearization"
                                }
                            ], 
                            "description": "Minima, maxima, and critical points.  Rates of change. Optimization. L'Hopital's rule.  Mean value theorem.", 
                            "id": "derivative_applications", 
                            "title": "Derivative applications"
                        }
                    ], 
                    "description": "", 
                    "id": "differential-calculus", 
                    "title": "Differential calculus"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "You are very familiar with taking the derivative of a function.  Now we are going to go the other way around--if I give you a derivative of a function, can you come up with a possible original function.  In other words, we'll be taking the anti-derivative!", 
                                    "id": "indefinite_integrals", 
                                    "title": "Indefinite integral as anti-derivative"
                                }, 
                                {
                                    "description": "In this tutorial, we'll think about how we can find the area under a curve.  We'll first approximate this with rectangles (and trapezoids)--generally called Riemann sums.  We'll then think about find the exact area by having the number of rectangles approach infinity (they'll have infinitesimal widths) which we'll use the definite integral to denote.", 
                                    "id": "riemann-sums", 
                                    "title": "Riemann sums"
                                }, 
                                {
                                    "description": "Until now, we have been viewing integrals as anti-derivatives.  Now we explore them as the area under a curve between two boundaries (we will now construct definite integrals by defining the boundaries).  This is the real meat of integral calculus!", 
                                    "id": "definite_integrals", 
                                    "title": "Definite integrals"
                                }, 
                                {
                                    "description": "Let's explore functions defined by definite integrals.  It will hopefully give you a deeper appreciation of what a definite integral represents.", 
                                    "id": "functions-defined-by-integrals", 
                                    "title": "Functions defined by integrals"
                                }, 
                                {
                                    "description": "You get the general idea that taking a definite integral of a function is related to evaluating the antiderivative, but where did this connection come from.  This tutorial focuses on the fundamental theorem of calculus which ties the ideas of integration and differentiation together.  We'll explain what it is, give a proof and then show examples of taking derivatives of integrals where the Fundamental Theorem is directly applicable.", 
                                    "id": "fundamental-theorem-of-calculus", 
                                    "title": "Fundamental theorem of calculus"
                                }, 
                                {
                                    "description": "When we wanted to take the derivative of f(x)g(x) in differential calculus, we used the product rule.  In this tutorial, we use the product rule to derive a powerful way to take the anti-derivative of a class of functions--integration by parts.", 
                                    "id": "integration_by_parts", 
                                    "title": "Integration by parts"
                                }, 
                                {
                                    "description": "U-substitution is a must-have tool for any integrating arsenal (tools aren't normally put in arsenals, but that sounds better than toolkit).  It is essentially the reverise chain rule.  U-substitution is very useful for any integral where an expression is of the form g(f(x))f'(x)(and a few other cases).  Over time, you'll be able to do these in your head without necessarily even explicitly substituting. \n\nWhy the letter \"u\"?  Well, it could have been anything, but this is the convention.  I guess why not the letter \"u\" :)", 
                                    "id": "u_substitution", 
                                    "title": "u-substitution"
                                }, 
                                {
                                    "description": "We will now do another substitution technique (the other was u-substitution) where we substitute variables with trig functions.  This allows us to leverage some trigonometric identities to simplify the expression into one that it is easier to take the anti-derivative of.", 
                                    "id": "trig_substitution", 
                                    "title": "Trigonometric substitution"
                                }, 
                                {
                                    "description": "Not everything (or everyone) should or could be proper all the time.  Same is true for definite integrals.  In this tutorial, we'll look at improper integrals--ones where one or both bounds are at infinity!  Mind blowing!", 
                                    "id": "improper-integrals-tutorial", 
                                    "title": "Improper integrals"
                                }, 
                                {
                                    "description": "We don't need calculus to figure out the average value of a linear function over an interval, but what about non-linear functions?  Luckily, integral calculus comes to the rescue here.  In this tutorial, we'll understand what \"average value\" of a function over an interval means.  We'll also connect that notion to the Mean Value Theorem we first learned in differential calculus.", 
                                    "id": "function-average-value", 
                                    "title": "Average value of a function"
                                }
                            ], 
                            "description": "Indefinite integral as anti-derivative.  Definite integral as area under a curve.  Integration by parts.  U-substitution.  Trig substitution.", 
                            "id": "indefinite-definite-integrals", 
                            "title": "Indefinite and definite integrals"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "You know how to use definite integrals to find areas under curves.  We now take that idea for \"spin\" by thinking about the volumes of things created when you rotate functions around various lines. \n\nThis tutorial focuses on the \"disc method\" and the \"washer method\" for these types of problems.", 
                                    "id": "disc-method", 
                                    "title": "Disc method"
                                }, 
                                {
                                    "description": "You want to rotate a function around a vertical line, but do all your integrating in terms of x and f(x), then the shell method is your new friend.  It is similarly fantastic when you want to rotate around a horizontal line but integrate in terms of y.", 
                                    "id": "shell-method", 
                                    "title": "Shell method"
                                }, 
                                {
                                    "description": "Using definite integration, we know how to find the area under a curve.  But what about the volume of the 3-D shape generated by rotating a section of the curve about one of the axes (or any horizontal or vertical line for that matter).  This in an older tutorial that is now covered in other tutorials.\n\nThis tutorial will give you a powerful tool and stretch your powers of 3-D visualization!", 
                                    "id": "solid_of_revolution", 
                                    "title": "Solid of revolution volume"
                                }
                            ], 
                            "description": "Using definite integrals with the shell and disc methods to find volumes of solids of revolution.", 
                            "id": "solid_revolution_topic", 
                            "title": "Solids of revolution"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "In this tutorial, we'll review what sequences are, associated notation and convergence/divergence of sequences.", 
                                    "id": "calculus-sequences", 
                                    "title": "Sequences"
                                }, 
                                {
                                    "description": "Now that we understand what a sequence is, we're going to think about what happens to the terms of a sequence at infinity (do they approach 0, a finite value, or +- infinity?).", 
                                    "id": "seq-conv-diverg", 
                                    "title": "Sequence convergence and divergence"
                                }, 
                                {
                                    "description": "You're familiar with sequences and have been eager to sum them up.  Well wait no longer!  In this tutorial, we'll see that series are just sums of sequences and familiarize ourselves with the notation.\n", 
                                    "id": "calculus-series", 
                                    "title": "Series"
                                }, 
                                {
                                    "description": "Whether you are computing mortgage payments or calculating the distance traveled by a bouncing ball, geometric  series show up in life far more than you imagine.  This tutorial will review all the important concepts and more!", 
                                    "id": "seq_series_review", 
                                    "title": "Geometric series"
                                }, 
                                {
                                    "description": "Now that we're familiar with the idea of an infinite series, we can now think about functions that are defined using infinite series.  In particular, we'll begin to look at the power series representation of a function (and the special case of a geometric series).  In later tutorials, we'll use calculus to find the power series of more types of functions.", 
                                    "id": "power-series-algebra", 
                                    "title": "Power series function representation using algebra"
                                }, 
                                {
                                    "description": "In this tutorial, we will learn to approximate differentiable functions with polynomials.  Beyond just being super cool, this can be useful for approximating functions so that they are easier to calculate, differentiate or integrate.  So whether you will have to write simulations or become a bond trader (bond traders use polynomial approximation to estimate changes in bond prices given interest rate changes and vice versa), this tutorial could be fun.\n\nIf that isn't motivation enough, we also come up with one of the most epic and powerful conclusions in all of mathematics in this tutorial: Euler's identity.", 
                                    "id": "maclaurin_taylor", 
                                    "title": "Maclaurin series and Euler's identity"
                                }, 
                                {
                                    "description": "As we've already seen, Maclaurin series are special cases of Taylor series centered at 0.  We'll now focus on more generalized Taylor series.", 
                                    "id": "taylor-series", 
                                    "title": "Taylor series approximations"
                                }, 
                                {
                                    "description": "Everything in this tutorial is covered (with better resolution and handwriting) in the \"other\" Maclaurin and Taylor series tutorial, but this one has a bit of old-school charm so we are keeping it here for historical reasons.", 
                                    "id": "old_maclaurin_series", 
                                    "title": "Sal's old Maclaurin and Taylor series tutorial"
                                }
                            ], 
                            "description": "Sequences, series and approximating functions.  Maclaurin and Taylor series.", 
                            "id": "sequences_series_approx_calc", 
                            "title": "Sequences, series and function approximation"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Many of you are planning on taking the Calculus AB advanced placement exam.  These are example problems taken directly from previous years' exams. Even if you aren't taking the exam, these are very useful problem for making sure you understand your calculus (as always, best to pause the videos and try them yourself before Sal does).", 
                                    "id": "ab_examples", 
                                    "title": "Calculus AB example questions"
                                }, 
                                {
                                    "description": "The Calculus BC AP exam is a super set of the AB exam.  It covers everything in AB as well as some of the more advanced topics in integration, sequences and function approximation.  This tutorial is great practice for anyone looking to test their calculus mettle!", 
                                    "id": "bc_sample_questions", 
                                    "title": "Calculus BC sample questions"
                                }
                            ], 
                            "description": "Sample questions from the A.P. Calculus AB and BC exams (both multiple choice and free answer).", 
                            "id": "ap_calc_topic", 
                            "title": "AP Calculus practice questions"
                        }
                    ], 
                    "description": "", 
                    "id": "integral-calculus", 
                    "title": "Integral calculus"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "A single definite integral can be used to find the area under a curve.  with double integrals, we can start thinking about the volume under a surface!", 
                                    "id": "double_integrals", 
                                    "title": "Double integrals"
                                }, 
                                {
                                    "description": "This is about as many integrals we can use before our brains explode.  Now we can sum variable quantities in three-dimensions (what is the mass of a 3-D wacky object that has variable mass)!", 
                                    "id": "triple_integrals", 
                                    "title": "Triple integrals"
                                }
                            ], 
                            "description": "Volume under a surface with double integrals. Triple integrals as well.", 
                            "id": "double_triple_integrals", 
                            "title": "Double and triple integrals"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Let's jump out of that boring (okay, it wasn't THAT boring) 2-D world into the exciting 3-D world that we all live and breath in.  Instead of functions of x that can be visualized as lines, we can have functions of x and y that can be visualized as surfaces.  But does the idea of a derivative still make sense?  Of course it does!  As long as you specify what direction you're going in. Welcome to the world of partial derivatives!", 
                                    "id": "partial_derivatives", 
                                    "title": "Partial derivatives"
                                }, 
                                {
                                    "description": "Ever walk on hill (or any wacky surface) and wonder which way would be the fastest way up (or down).  Now you can figure this out exactly with the gradient.", 
                                    "id": "gradient", 
                                    "title": "Gradient"
                                }, 
                                {
                                    "description": "Is a vector field \"coming together\" or \"drawing apart\" at a given point in space.  The divergence is a vector operator that gives us a scalar value at any point in a vector field.  If it is positive, then we are diverging.  Otherwise, we are converging!", 
                                    "id": "divergence", 
                                    "title": "Divergence"
                                }, 
                                {
                                    "description": "Curl measures how much a vector field is \"spinning\".  A bit of a pain to calculate, but could come in handy when we work with Stokes' and Greens' theorems later on.", 
                                    "id": "curl", 
                                    "title": "Curl"
                                }
                            ], 
                            "description": "Thinking about forms of derivatives in multi-dimensions and for vector-valued functions:  partial derivatives, gradient, divergence and curl.", 
                            "id": "partial_derivatives_topic", 
                            "title": "Partial derivatives, gradient, divergence, curl"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "With traditional integrals, our \"path\" was straight and linear (most of the time, we traversed the x-axis).  Now we can explore taking integrals over any line or curve (called line integrals).", 
                                    "id": "line_integrals", 
                                    "title": "Line integrals for scalar functions"
                                }, 
                                {
                                    "description": "In this tutorial, we will explore position vector functions and think about what it means to take a derivative of one.  Very valuable for thinking about what it means to take a line integral along a path in a vector field (next tutorial).", 
                                    "id": "position_vector_functions", 
                                    "title": "Position vector functions and derivatives"
                                }, 
                                {
                                    "description": "You've done some work with line integral with scalar functions and you know something about parameterizing position-vector valued functions.  In that case, welcome!  You are now ready to explore a core tool math and physics: the line integral for vector fields.  Need to know the work done as a mass is moved through a gravitational field.  No sweat with line integrals.", 
                                    "id": "line_integrals_vectors", 
                                    "title": "Line integrals in vector fields"
                                }, 
                                {
                                    "description": "It is sometimes easier to take a double integral (a particular double integral as we'll see) over a region and sometimes easier to take a line integral around the boundary.  Green's theorem draws the connection between the two so we can go back and forth.  This tutorial proves Green's theorem and then gives a few examples of using it.  If you can take line integrals through vector fields, you're ready for Mr. Green.", 
                                    "id": "greens_theorem", 
                                    "title": "Green's theorem"
                                }, 
                                {
                                    "description": "Using Green's theorem (which you should already be familiar with) to establish that the \"flux\" through the boundary of a region is equal to the double integral of the divergence over the region.  We'll also talk about why this makes conceptual sense.", 
                                    "id": "2d_divergence_theorem", 
                                    "title": "2D divergence theorem"
                                }
                            ], 
                            "description": "Line integral of scalar and vector-valued functions.  Green's theorem and 2-D divergence theorem.", 
                            "id": "line_integrals_topic", 
                            "title": "Line integrals and Green's theorem"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "You can parameterize a line with a position vector valued function and understand what a differential means in that context already.  This tutorial will take things further by parametrizing surfaces (2 parameters baby!) and have us thinking about partial differentials.", 
                                    "id": "surface_parametrization", 
                                    "title": "Parameterizing a surface"
                                }, 
                                {
                                    "description": "Finding line integrals to be a bit boring? Well, this tutorial will add new dimension to your life by explore what surface integrals are and how we can calculate them.", 
                                    "id": "surface_integrals", 
                                    "title": "Surface integrals"
                                }, 
                                {
                                    "description": "Flux can be view as the rate at which \"stuff\" passes through a surface.  Imagine a net placed in a river and imagine the water that is flowing directly across the net in a unit of time--this is flux (and it would depend on the orientation of the net, the shape of the net, and the speed and direction of the current). It is an important idea throughout physics and is key for understanding Stokes' theorem and the divergence theorem.", 
                                    "id": "3d_flux", 
                                    "title": "Flux in 3D and constructing unit normal vectors to surface"
                                }, 
                                {
                                    "description": "Stokes' theorem relates the line integral around a surface to the curl on the surface. This tutorial explores the intuition behind Stokes' theorem, how it is an extension of Green's theorem to surfaces (as opposed to just regions) and gives some examples using it.  We prove Stokes' theorem in another tutorial.  Good to come to this tutorial having experienced the tutorial on \"flux in 3D\".", 
                                    "id": "stokes_theorem", 
                                    "title": "Stokes' theorem intuition and application"
                                }, 
                                {
                                    "description": "You know what Stokes' theorem is and how to apply it, but are craving for some real proof that it is true.  Well, you've found the right tutorial!", 
                                    "id": "stokes_proof", 
                                    "title": "Proof of Stokes' theorem"
                                }
                            ], 
                            "description": "Parameterizing a surface.  Surface integrals. Stokes' theorem.", 
                            "id": "surface-integrals", 
                            "title": "Surface integrals and Stokes' theorem"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "An earlier tutorial used Green's theorem to prove the divergence theorem in 2-D, this tutorial gives us the 3-D version (what most people are talking about when they refer to the \"divergence theorem\").  We will get an intuition for it (that the flux through a close surface--like a balloon--should be equal to the divergence across it's volume).  We will use it in examples.  We will prove it in another tutorial.", 
                                    "id": "divergence_theorem", 
                                    "title": "Divergence theorem (3D)"
                                }, 
                                {
                                    "description": "This tutorial classifies regions in three dimensions.  Comes in useful for some types of double integrals and we use these ideas to prove the divergence theorem.", 
                                    "id": "region_types_3d", 
                                    "title": "Types of regions in three dimensions"
                                }, 
                                {
                                    "description": "You know what the divergence theorem is, you can apply it and you conceptually understand it.  This tutorial will actually prove it to you (references types of regions which are covered in the \"types of regions in 3d\" tutorial.", 
                                    "id": "divergence_theorem_proof", 
                                    "title": "Divergence theorem proof"
                                }
                            ], 
                            "description": "Divergence theorem intuition.  Divergence theorem examples and proofs.  Types of regions in 3D.", 
                            "id": "divergence_theorem_topic", 
                            "title": "Divergence theorem"
                        }
                    ], 
                    "description": "Topics covered in the first two or three semesters of college calculus.  Everything from limits to derivatives to integrals to vector calculus. Should understand the topics in the pre-calculus playlist first (the limit videos are in both playlists)", 
                    "id": "multivariable-calculus", 
                    "title": "Multivariable calculus"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "How is a differential equation different from a regular one?  Well, the solution is a function (or a class of functions), not a number.  How do you like me now (that is what the differential equation would say in response to your shock)!", 
                                    "id": "differential-equations-intro", 
                                    "title": "Intro to differential equations"
                                }, 
                                {
                                    "description": "Arguably the 'easiest' class of differential equations.  Here we use our powers of algebra to \"separate\" the y's from the x's on two different sides of the equation and then we just integrate!", 
                                    "id": "separable-equations", 
                                    "title": "Separable equations"
                                }, 
                                {
                                    "description": "A very special class of often non-linear differential equations.  If you know a bit about partial derivatives, this tutorial will help you know how to 'exactly' solve these!", 
                                    "id": "exact-equations", 
                                    "title": "Exact equations and integrating factors"
                                }, 
                                {
                                    "description": "In this equations, all of the fat is fully mixed in so it doesn't collect at the top.  No (that would be homogenized equations).\n\nActually, the term \"homogeneous\" is way overused in differential equations.  In this tutorial, we'll look at equations of the form y'=(F(y/x)).", 
                                    "id": "homogeneous-equations", 
                                    "title": "Homogeneous equations"
                                }
                            ], 
                            "description": "Differential equations with only first derivatives.", 
                            "id": "first-order-differential-equations", 
                            "title": "First order differential equations"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "To make your life interesting, we'll now use the word \"homogeneous\" in a way that is not connected to the way we used the term when talking about first-order equations.  As you'll see, second order linear homogeneous equations can be solved with a little bit of algebra (and a lot of love).", 
                                    "id": "linear-homogeneous-2nd-order", 
                                    "title": "Linear homogeneous equations"
                                }, 
                                {
                                    "description": "Thinking about what happens when you have complex or repeated roots for your characteristic equation.", 
                                    "id": "complex-roots-characteristic-equation", 
                                    "title": "Complex and repeated roots of characteristic equation"
                                }, 
                                {
                                    "description": "Now we can apply some of our second order linear differential equations skills to nonhomogeneous equations.  Yay!", 
                                    "id": "undetermined-coefficients", 
                                    "title": "Method of undetermined coefficients"
                                }
                            ], 
                            "description": "Linear differential equations that contain second derivatives", 
                            "id": "second-order-differential-equations", 
                            "title": "Second order linear equations"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "We now use one of the coolest techniques in mathematics to transform differential equations into algebraic ones. You'll also learn about transforms in general!", 
                                    "id": "laplace-transform-tutorial", 
                                    "title": "Laplace transform"
                                }, 
                                {
                                    "description": "You know how to use the definition of the Laplace transform.  In this tutorial, we'll explore some of the properties of the transform that will start to make it clear why they are so useful for differential equations.\n\nThis tutorial is paired well with the tutorial on using the \"Laplace transform to solve differential equations\".  In fact you  might come back to this tutorial over and over as you solve more and more problems.", 
                                    "id": "properties-of-laplace-transform", 
                                    "title": "Properties of the Laplace transform"
                                }, 
                                {
                                    "description": "You know a good bit about taking Laplace transform and useful properties of the transform.  You are dying to actually apply these skills to an actual differential equation.  Wait no longer!", 
                                    "id": "laplace-transform-to-solve-differential-equation", 
                                    "title": "Laplace transform to solve a differential equation"
                                }, 
                                {
                                    "description": "This tutorial won't be as convoluted as you might suspect.  We'll see what multiplying transforms in the s-domain give us in the time domain.", 
                                    "id": "convolution-integral", 
                                    "title": "The convolution integral"
                                }
                            ], 
                            "description": "Transforms and the Laplace transform in particular. Convolution integrals.", 
                            "id": "laplace-transform", 
                            "title": "Laplace transform"
                        }
                    ], 
                    "description": "Topics covered in a first year course in differential equations.  Need to understand basic differentiation and integration from Calculus playlist before starting here.", 
                    "id": "differential-equations", 
                    "title": "Differential equations"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "We will begin our journey through linear algebra by defining and conceptualizing what a vector is (rather than starting with matrices and matrix operations like in a more basic algebra course) and defining some basic operations (like addition, subtraction and scalar multiplication).", 
                                    "id": "vectors", 
                                    "title": "Vectors"
                                }, 
                                {
                                    "description": "Given a set of vectors, what other vectors can you create by adding and/or subtracting scalar multiples of those vectors.  The set of vectors that you can create through these linear combinations of the original set is called the \"span\" of the set.", 
                                    "id": "linear_combinations", 
                                    "title": "Linear combinations and spans"
                                }, 
                                {
                                    "description": "If no vector in a set can be created from a linear combination of the other vectors in the set, then we say that the set in linearly independent.  Linearly independent sets are great because there aren't any extra, unnecessary vectors lying around in the set. :)", 
                                    "id": "linear_independence", 
                                    "title": "Linear dependence and independence"
                                }, 
                                {
                                    "description": "In this tutorial, we'll define what a \"subspace\" is --essentially a subset of vectors that has some special properties.  We'll then think of a set of vectors that can most efficiently be use to construct a subspace which we will call a \"basis\".", 
                                    "id": "subspace_basis", 
                                    "title": "Subspaces and the basis for a subspace"
                                }, 
                                {
                                    "description": "In this tutorial, we define two ways to \"multiply\" vectors-- the dot product and the cross product.  As we progress, we'll get an intuitive feel for their meaning, how they can used and how the two vector products relate to each other.", 
                                    "id": "dot_cross_products", 
                                    "title": "Vector dot and cross products"
                                }, 
                                {
                                    "description": "We will define matrix-vector multiplication and think about the set of vectors that satisfy Ax=0 for a given matrix A (this is the null space of A).  We then proceed to think about the linear combinations of the columns of a matrix (column space).  Both of these ideas help us think the possible solutions to the Matrix-vector equation Ax=b.", 
                                    "id": "null_column_space", 
                                    "title": "Null space and column space"
                                }
                            ], 
                            "description": "Let's get our feet wet by thinking in terms of vectors and spaces.", 
                            "id": "vectors_and_spaces", 
                            "title": "Vectors and spaces"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "People have been telling you forever that linear algebra and matrices are useful for modeling, simulations and computer graphics, but it has been a little non-obvious.  This tutorial will start to draw the lines by re-introducing you functions (a bit more rigor than you may remember from high school) and linear functions/transformations in particular.", 
                                    "id": "linear_transformations", 
                                    "title": "Functions and linear transformations"
                                }, 
                                {
                                    "description": "In this tutorial, we do several examples of actually constructing transformation matrices.  Very useful if you've got some actual transforming to do (especially scaling, rotating and projecting) ;)", 
                                    "id": "lin_trans_examples", 
                                    "title": "Linear transformation examples"
                                }, 
                                {
                                    "description": "You probably remember how to multiply matrices from high school, but didn't know why or what it represented.  This tutorial will address this.  You'll see that multiplying two matrices can be view as the composition of linear transformations.", 
                                    "id": "composition_of_transformations", 
                                    "title": "Transformations and matrix multiplication"
                                }, 
                                {
                                    "description": "You can use a transformation/function to map from one set to another, but can you invert it?  In other words, is there a function/transformation that given the output of the original mapping, can output the original input (this is much clearer with diagrams).  \n\nThis tutorial addresses this question in a linear algebra context.  Since matrices can represent linear transformations, we're going to spend a lot of time thinking about matrices that represent the inverse transformation.", 
                                    "id": "inverse_transformations", 
                                    "title": "Inverse functions and transformations"
                                }, 
                                {
                                    "description": "We've talked a lot about inverse transformations abstractly in the last tutorial.  Now, we're ready to actually compute inverses.  We start from \"documenting\" the row operations to get a matrix into reduced row echelon form and use this to come up with the formula for the inverse of a 2x2 matrix.  After this we define a determinant for 2x2, 3x3 and nxn matrices.", 
                                    "id": "inverse_of_matrices", 
                                    "title": "Finding inverses and determinants"
                                }, 
                                {
                                    "description": "In the last tutorial on matrix inverses, we first defined what a determinant is and gave several examples of computing them.  In this tutorial we go deeper.  We will explore what happens to the determinant under several circumstances and conceptualize it in several ways.", 
                                    "id": "determinant_depth", 
                                    "title": "More determinant depth"
                                }, 
                                {
                                    "description": "We now explore what happens when you switch the rows and columns of a matrix!", 
                                    "id": "matrix_transpose", 
                                    "title": "Transpose of a matrix"
                                }
                            ], 
                            "description": "Understanding how we can map one set of vectors to another set.  Matrices used to define linear transformations.", 
                            "id": "matrix_transformations", 
                            "title": "Matrix transformations"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "We will know explore the set of vectors that is orthogonal to every vector in a second set (this is the second set's orthogonal complement).", 
                                    "id": "othogonal_complements", 
                                    "title": "Orthogonal complements"
                                }, 
                                {
                                    "description": "This is one of those tutorials that bring many ideas we've been building together into something applicable.  Orthogonal projections (which can sometimes be conceptualized as a \"vector's shadow\" on a subspace if the light source is above it) can be used in fields varying from computer graphics and statistics!\n\nIf you're familiar with orthogonal complements, then you're ready for this tutorial!", 
                                    "id": "orthogonal_projections", 
                                    "title": "Orthogonal projections"
                                }, 
                                {
                                    "description": "Finding a coordinate system boring.  Even worse, does it make certain transformations difficult (especially transformations that you have to do over and over and over again)?  Well, we have the tool for you:  change your coordinate system to one that you like more.  Sound strange?  Watch this tutorial and it will be less so.  Have fun!", 
                                    "id": "change_of_basis", 
                                    "title": "Change of basis"
                                }, 
                                {
                                    "description": "As we'll see in this tutorial, it is hard not to love a basis where all the vectors are orthogonal to each other and each have length 1 (hey, this sounds pretty much like some coordinate systems you've known for a long time!).  We explore these orthonormal bases in some depth and also give you a great tool for creating them: the Gram-Schmidt Process (which would also be a great name for a band).", 
                                    "id": "orthonormal_basis", 
                                    "title": "Orthonormal bases and the Gram-Schmidt process"
                                }, 
                                {
                                    "description": "Eigenvectors, eigenvalues, eigenspaces!  We will not stop with the \"eigens\"!  Seriously though, eigen-everythings have many applications including finding \"good\" bases for a transformation (yes, \"good\" is a technical term in this context).", 
                                    "id": "eigen_everything", 
                                    "title": "Eigen-everything"
                                }
                            ], 
                            "description": "We explore creating and moving between various coordinate systems.", 
                            "id": "alternate_bases", 
                            "title": "Alternate coordinate systems (bases)"
                        }
                    ], 
                    "description": "Matrices, vectors, vector spaces, transformations, eigenvectors/values.  Covers all topics in a first year college linear algebra course.  This is an advanced course normally taken by science or engineering majors after taking at least two semesters of calculus (although calculus really isn't a prereq) so don't confuse this with regular high school algebra.", 
                    "id": "linear-algebra", 
                    "title": "Linear algebra"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "You're feeling spirally today, and math class today is taking place in greenhouse #3...", 
                                    "id": "spirals-fibonacci", 
                                    "title": "Spirals, Fibonacci and being a plant"
                                }, 
                                {
                                    "description": "Let's say you're me and you're in math class\u2026", 
                                    "id": "doodling-in-math", 
                                    "title": "Doodling in math"
                                }, 
                                {
                                    "description": "Since it's shaped like a hexagon and flex rhymes with hex, hexaflexagon it is!", 
                                    "id": "hexaflexagons", 
                                    "title": "Hexaflexagons"
                                }, 
                                {
                                    "description": "When you want to make a circle, how is it done?  Well you probably will start with the radius one.", 
                                    "id": "pi-tau", 
                                    "title": "About pi and tau"
                                }, 
                                {
                                    "description": "The title says it all...", 
                                    "id": "singing", 
                                    "title": "Singing (and noises)"
                                }, 
                                {
                                    "description": "Playing mathematically with strips!", 
                                    "id": "mobius-strips", 
                                    "title": "Mobius strips"
                                }, 
                                {
                                    "description": "Mathed potatoes, Borromean onion rings, green bean matheroles and Turduckenen-duckenen (yes, you read that right)", 
                                    "id": "thanksgiving-math", 
                                    "title": "Thanksgiving math"
                                }, 
                                {
                                    "description": "Understanding infinity (all different kinds!). Countable and uncountable infinities. Bigger and smaller infinities. ", 
                                    "id": "infinity", 
                                    "title": "Infinity . . ."
                                }, 
                                {
                                    "description": "Pythagoras, snakes, fractals, snowflakes...", 
                                    "id": "vi-cool-stuff", 
                                    "title": "Other cool stuff"
                                }
                            ], 
                            "description": "Recreational mathematics and inspirational videos by resident mathemusician Vi Hart", 
                            "id": "vi-hart", 
                            "title": "Doodling in Math and more"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Random logic puzzles and brain teasers.  Fun to do and useful for many job interviews!", 
                                    "id": "brain-teasers", 
                                    "title": "Brain teasers"
                                }, 
                                {
                                    "description": "Random puzzles involving rotating, reflecting, and dilating polygons.", 
                                    "id": "transformation-puzzles", 
                                    "title": "Transformation Puzzles"
                                }, 
                                {
                                    "description": "Try to light up all the tiles!", 
                                    "id": "lights-puzzles", 
                                    "title": "Lights Puzzles"
                                }
                            ], 
                            "description": "", 
                            "id": "puzzles", 
                            "title": "Puzzles"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "The 'problem of points' is a classic problem Fermat and Pascal famously debated in the 17th century. Their solution to this problem formed the basis of modern day probability theory. Now it's your turn to relive this challenge!\n", 
                                    "id": "probabilty-warmup", 
                                    "title": "Expectation warmup"
                                }, 
                                {
                                    "description": "Introduction to random sampling (also known as the weak law of large numbers)", 
                                    "id": "random-sample-warmup", 
                                    "title": "Random sampling warmup"
                                }, 
                                {
                                    "description": "Introduction to independent events and frequency analysis using histograms.\n", 
                                    "id": "independent-events-warmup", 
                                    "title": "Independent events warmup"
                                }, 
                                {
                                    "description": "Introduction to probability distributions, center, spread, and overall shape. In this warmup we will discover the binomial distribution!", 
                                    "id": "distribution-warmup", 
                                    "title": "Distribution warmup"
                                }, 
                                {
                                    "description": "Arithmetic warmups", 
                                    "id": "arithmetic-warmups", 
                                    "title": "Arithmetic warmups"
                                }, 
                                {
                                    "description": "Warmups related to number theory", 
                                    "id": "number-theory-warmups", 
                                    "title": "Number Theory warmups"
                                }
                            ], 
                            "description": "Introducing key concepts using physical analogies", 
                            "id": "math-warmup", 
                            "title": "Math warmups"
                        }
                    ], 
                    "description": "", 
                    "id": "recreational-math", 
                    "title": "Recreational math"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "Final five questions on the 2013 AMC 10 A. (Three of these problems are shared with the 2013 AMC 12 A.)\n\nVideos produced by Art of Problem Solving (www.aops.com).  Problems from the MAA American Mathematics Competitions (amc.maa.org)", 
                                    "id": "2013-amc-10-a", 
                                    "title": "2013 AMC 10 A"
                                }
                            ], 
                            "description": "The AMC 10 is part of the series of contests administered by the MAA American Mathematics Competitions that determines the United States team in the International Math Olympiad. The AMC 10 is a 25 question, 75 minute multiple choice test for students in 10th grade or below. Two versions of the AMC 10 are offered each year.", 
                            "id": "amc-10", 
                            "title": "AMC 10"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "2003-aime", 
                                    "title": "2003 AIME"
                                }
                            ], 
                            "description": "", 
                            "id": "aime", 
                            "title": "AIME"
                        }
                    ], 
                    "description": "Problems from prestigious American middle and high school competitions.", 
                    "id": "competition-math", 
                    "title": "Math contests"
                }
            ], 
            "description": "Watch videos and practice your skills for almost any math subject.", 
            "id": "math", 
            "title": "Math"
        }, 
        {
            "children": [
                {
                    "children": [
                        {
                            "description": "", 
                            "id": "evolution-and-natural-selection", 
                            "title": "Evolution and natural selection"
                        }, 
                        {
                            "description": "", 
                            "id": "cell-division", 
                            "title": "Cells"
                        }, 
                        {
                            "description": "", 
                            "id": "new-topic-2014-06-18T18:00:45.081Z", 
                            "title": "Cell division"
                        }, 
                        {
                            "description": " ", 
                            "id": "heredity-and-genetics", 
                            "title": "Heredity and genetics"
                        }, 
                        {
                            "description": "", 
                            "id": "tree-of-life", 
                            "title": "Tree of life"
                        }, 
                        {
                            "description": "", 
                            "id": "cellular-respiration", 
                            "title": "Cellular respiration"
                        }, 
                        {
                            "description": "", 
                            "id": "photosynthesis", 
                            "title": "Photosynthesis"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "As humans, we really like breathing oxygen.  That's because the cells in our body will die if they don't get oxygen to function in a reasonable amount of time.  This tutorials describes how we use the lungs to exchange gasses between our blood and the atmosphere and how the oxygen is then pumped through the body by way of blood and the circulatory system.", 
                                    "id": "circulatory-pulmonary", 
                                    "title": "Circulatory and pulmonary systems"
                                }, 
                                {
                                    "description": "Neurons are the primary way that our bodies transmit signals from one part to another quickly.  In this tutorial, we'll explore the anatomy of a neuron and the mechanism by which a signal is actually transmitted through one.", 
                                    "id": "neuron-nervous-system", 
                                    "title": "The neuron and nervous system"
                                }, 
                                {
                                    "description": "How do we get unwanted substances out of our blood?  Through the kidney.  This tutorial goes into some detail to describe just how this happens.", 
                                    "id": "kidney-nephron", 
                                    "title": "The kidney and nephron"
                                }, 
                                {
                                    "description": "Without muscles, we wouldn't be able to do much of anything.  This tutorial begins to explore what muscle cells are and how they contract in order to move our bodies (or do things like breath and pump blood).", 
                                    "id": "muscles", 
                                    "title": "Muscles"
                                }
                            ], 
                            "description": "", 
                            "id": "human-biology", 
                            "title": "Human biology"
                        }, 
                        {
                            "description": "", 
                            "id": "immunology", 
                            "title": "Immunology"
                        }, 
                        {
                            "description": "Hank Green teaches you biology! \nLearn, study and understand the science of life. \nTopics covered range from: taxonomy, systems, biological molecules, photosynthesis, evolution, animals, plants, anatomy, and ecology.", 
                            "id": "crash-course-biology-science", 
                            "title": "Crash Course: Biology"
                        }, 
                        {
                            "description": "Hank Green teaches you ecology!  \nLearn, study and understand how organisms relate to one another and to their surroundings.  Start with the history of life on earth, then cover topics ranging from population ecology, community ecology, ecosystem ecology, to conservation and restoration ecology.", 
                            "id": "crash-course-ecology-2", 
                            "title": "Crash Course: Ecology"
                        }
                    ], 
                    "description": "Covers topics seen in a first year college or high school biology course.", 
                    "id": "biology", 
                    "title": "Biology"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "This tutorial is the backbone of your understanding of kinematics (i.e., the motion of objects).  You might already know that distance = rate x time.  This tutorial essentially reviews that idea with a vector lens (we introduce you to vectors here as well).  So strap your belts (actually this might not be necessary since we don't plan on decelerating in this tutorial) and prepare for a gentle ride of foundational physics knowledge.", 
                                    "id": "displacement-velocity-time", 
                                    "title": "Displacement, velocity and time"
                                }, 
                                {
                                    "description": "In a world full of unbalanced forces (which you learn more about when you study Newton's laws), you will have acceleration (which is the rate in change of velocity).  Whether you're thinking about how fast a Porsche can get to 60mph or how long it takes for a passenger plane to get to the necessary speed for flight, this tutorial will help.", 
                                    "id": "acceleration_tutorial", 
                                    "title": "Acceleration"
                                }, 
                                {
                                    "description": "We don't believe in memorizing formulas and neither should you (unless you want to live your life as a shadow of your true potential).  This tutorial builds on what we know about displacement, velocity and acceleration to solve problems in kinematics (including projectile motion problems).  Along the way, we derive (and re-derive) some of the classic formulas that you might see in your physics book.", 
                                    "id": "kinematic_formulas", 
                                    "title": "Kinematic formulas and projectile motion"
                                }, 
                                {
                                    "description": "This tutorial has some of the old videos that Sal first did around 2007.  This content is covered elsewhere, but some folks like the raw (and masculine) simplicity of these first lessons (Sal added the bit about \"masculine\").", 
                                    "id": "old-projectile-motion", 
                                    "title": "Old videos on projectile motion"
                                }
                            ], 
                            "description": "In this tutorial we begin to explore ideas of velocity and acceleration.  We do exciting things like throw things off of cliffs (far safer on paper than in real life) and see how high a ball will fly in the air.", 
                            "id": "one-dimensional-motion", 
                            "title": "One-dimensional motion"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Let's escape from the binds of one-dimension (where we were forced to launch things straight up) and start launching at angles.  With a little bit of trig (might want to review sin and cos) we'll be figuring out just how long and far something can travel.", 
                                    "id": "two-dimensional-projectile-mot", 
                                    "title": "Two-dimensional projectile motion"
                                }, 
                                {
                                    "description": "This tutorial tackles a fundamental question when trying to launch things as far as possible (key if you're looking to capture a fort with anything from water balloons to arrows).  With a bit of calculus, we'll get to a fairly intuitive answer.", 
                                    "id": "optimal-projectile-angle", 
                                    "title": "Optimal angle for a projectile"
                                }, 
                                {
                                    "description": "Why do things move in circles? Seriously.  Why does *anything* ever move in a circle (straight lines seem much more natural). ?  Is something moving in a circle at a constant speed accelerating?  If so, in what direction?  This tutorial will help you get mind around this super-fun topic.", 
                                    "id": "centripetal-acceleration-tutoria", 
                                    "title": "Centripetal acceleration"
                                }
                            ], 
                            "description": "You understand velocity and acceleration well in one-dimension.  Now we can explore scenarios that are even more fun.  With a little bit of trigonometry (you might want to review your basic trig, especially what sin and cos are), we can think about whether a baseball can clear the \"green monster\" at Fenway Park.", 
                            "id": "two-dimensional-motion", 
                            "title": "Two-dimensional motion"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "This tutorial will expose you to the foundation of classical mechanics--Newton's laws.  On one level they are intuitive, on another lever they are completely counter-intuitive.  Challenge your take on reality and watch this tutorial.  The world will look very different after you're done.", 
                                    "id": "newtons-laws-of-motion", 
                                    "title": "Newton's laws of motion"
                                }, 
                                {
                                    "description": "A dog is balancing on one arm on my head.  Is my head applying a force to the dog's hand?  If it weren't, wouldn't there be nothing to offset the pull of gravity causing the acrobatic dog to fall?  What would we call this force?  Can we have a general term from the component of a contact force that acts perpendicular to the plane of contact?  These are absolutely normal questions to ask.", 
                                    "id": "normal-contact-force", 
                                    "title": "Normal force and contact force"
                                }, 
                                {
                                    "description": "You will often hear physics professors be careful to say \"net force\" or \"unbalanced force\" rather than just \"force\".  Why?  This tutorial explains why and might give you more intuition about Newton's laws in the process.", 
                                    "id": "balanced-unbalanced-forces", 
                                    "title": "Balanced and unbalanced forces"
                                }, 
                                {
                                    "description": "This short tutorial will have you dealing with orbiting frozen socks in order to understand whether you understand Newton's Laws.  We also quiz you a bit during the videos just to make sure that you aren't daydreaming about what you would do with a frozen sock.", 
                                    "id": "lubricon-vi", 
                                    "title": "Slow sock on Lubricon VI"
                                }, 
                                {
                                    "description": "We've all slid down slides/snow-or-mud-covered-hills/railings at some point in our life (if not, you haven't really lived) and noticed that the smoother the surface the more we would accelerate (try to slide down a non-snow-or-mud-covered hill).  This tutorial looks into this in some depth.  We'll look at masses on inclined planes and think about static and kinetic friction.", 
                                    "id": "inclined-planes-friction", 
                                    "title": "Inclined planes and friction"
                                }, 
                                {
                                    "description": "Bad commute? Baby crying?  Bills to pay?  Looking to take a bath with some Calgon (do a search on YouTube for context) to ease your tension?  This tutorial has nothing (actually little, not nothing) to do with that.\n\nSo far, most of the forces we've been dealing with are forces of \"pushing\"--contact forces at the macro level because of atoms not wanting to get to close at the micro level.  Now we'll deal with \"pulling\" force or tension (at a micro level this is the force of attraction between bonded atoms).", 
                                    "id": "tension-tutorial", 
                                    "title": "Tension"
                                }
                            ], 
                            "description": "This tutorial is the meat of much of classical physics.  We think about what a force is and how Newton changed the world's (and possibly your) view of how reality works.", 
                            "id": "forces-newtons-laws", 
                            "title": "Forces and Newton's laws of motion"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "You're doing a lot more work than you realize (most of which goes unpaid).  This tutorial will have you seeing the world in terms of potentials and energy and work (which is more fun than you can possibly imagine).", 
                                    "id": "work-and-energy-tutorial", 
                                    "title": "Work and energy"
                                }, 
                                {
                                    "description": "If you have ever used a tool of any kind (including the bones in your body), you have employed mechanical advantage.  Whether you used an incline plane to drag something off of a pick-up truck, or the back of a hammer to remove a nail, the world of mechanical advantage surrounds us.", 
                                    "id": "mechanical-advantage", 
                                    "title": "Mechanical advantage"
                                }, 
                                {
                                    "description": "Weighing machines of all sorts employ springs that take a certain amount of force to keep compressed or stretched to a certain point.  Hooke's law will give us all the tools to weigh in on the subject ourselves and spring into action (yes, the puns are annoying us too)!", 
                                    "id": "hookes-law", 
                                    "title": "Springs and Hooke's law"
                                }
                            ], 
                            "description": "Work and energy.  Potential energy.  Kinetic energy.  Mechanical advantage.  Springs and Hooke's law.", 
                            "id": "work-and-energy", 
                            "title": "Work and energy"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Depending on your view of things, this may be the most violent of our tutorials.  Things will crash and collide.  We'll learn about momentum and how it is transferred.  Whether you're playing pool (or \"billiards\") or deciding whether you want to get tackled by the 300lb. guy, this tutorial is of key importance.", 
                                    "id": "momentum-tutorial", 
                                    "title": "Momentum"
                                }
                            ], 
                            "description": "Linear momentum.  Conservation of momentum.  Elastic collisions.", 
                            "id": "linear-momentum", 
                            "title": "Impacts and linear momentum"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Until this tutorial, we have been completely ignoring that things rotate.  In this tutorial, we'll explore why they rotate and how they do it.  It will leave your head spinning (no, it won't, but seemed like a fun thing to say given the subject matter).", 
                                    "id": "torque-tutorial", 
                                    "title": "Torque, moments, and angular momentum"
                                }
                            ], 
                            "description": "Thinking about making things rotate.  Center of mass, torque, moments and angular velocity.", 
                            "id": "torque-angular-momentum", 
                            "title": "Moments, torque, and angular momentum"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Why are you sticking to your chair (ignoring the spilled glue)?  Why does the earth orbit the sun (or does it)? How high could I throw my dog on the moon?\n\nGravitation defines our everyday life and the structure of the universe.  This tutorial will introduce it to you in the Newtonian sense.", 
                                    "id": "gravity-newtonian", 
                                    "title": "Newton's law of gravitation"
                                }
                            ], 
                            "description": "Classical gravity.  How masses attract each other (according to Newton).", 
                            "id": "newton-gravitation", 
                            "title": "Gravitation"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Every watch a slinky gyrate back and forth.  This is harmonic motion (a special class of oscillatory motion).  In this tutorial we'll see how we can model and deal with this type of phenomena.", 
                                    "id": "harmonic-motion", 
                                    "title": "Harmonic motion"
                                }
                            ], 
                            "description": "Pendulums.  Slinkies.  You when you have to use the bathroom but it is occupied.  These all go back and forth over and over and over again.  This tutorial explores this type of motion.", 
                            "id": "oscillatory-motion", 
                            "title": "Oscillatory motion"
                        }, 
                        {
                            "description": "", 
                            "id": "fluids", 
                            "title": "Fluids"
                        }, 
                        {
                            "description": "", 
                            "id": "thermodynamics", 
                            "title": "Thermodynamics"
                        }, 
                        {
                            "description": "", 
                            "id": "electricity-and-magnetism", 
                            "title": "Electricity and magnetism"
                        }, 
                        {
                            "description": "", 
                            "id": "waves-and-optics", 
                            "title": "Waves and optics"
                        }
                    ], 
                    "description": "Projectile motion, mechanics and electricity and magnetism.  Solid understanding of algebra and a basic understanding of trigonometry necessary.", 
                    "id": "physics", 
                    "title": "Physics"
                }, 
                {
                    "children": [
                        {
                            "description": "", 
                            "id": "introduction-to-the-atom", 
                            "title": "Introduction to the atom"
                        }, 
                        {
                            "description": "", 
                            "id": "orbitals-and-electrons", 
                            "title": "Orbitals and electrons"
                        }, 
                        {
                            "description": "", 
                            "id": "periodic-table-trends-bonding", 
                            "title": "Periodic table, trends, and bonding"
                        }, 
                        {
                            "description": "", 
                            "id": "chemical-reactions-stoichiometry", 
                            "title": "Chemical reactions (stoichiometry)"
                        }, 
                        {
                            "description": "", 
                            "id": "ideal-gas-laws", 
                            "title": "Ideal gas laws"
                        }, 
                        {
                            "description": "", 
                            "id": "states-of-matter", 
                            "title": "States of matter"
                        }, 
                        {
                            "description": "", 
                            "id": "reaction-rates", 
                            "title": "Reaction rates"
                        }, 
                        {
                            "description": "", 
                            "id": "acids-and-bases", 
                            "title": "Acids and bases"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Oxidation and reduction are powerful ideas for thinking about how charge is transferred within a reaction.  As we'll see, it is something of a hypothetical, but it is, nonetheless, very useful.", 
                                    "id": "redox-oxidation-reduction", 
                                    "title": "Redox reactions"
                                }, 
                                {
                                    "description": "Batteries power much of our lives (literally).  In this tutorial, we'll use our knowledge of oxidation and reduction to understand how Galvanic/Voltaic cells actually work.", 
                                    "id": "batter-galvanic-voltaic-cell", 
                                    "title": "Battery basics"
                                }
                            ], 
                            "description": "", 
                            "id": "oxidation-reduction", 
                            "title": "Oxidation reduction"
                        }, 
                        {
                            "description": "", 
                            "id": "radioactive-decay", 
                            "title": "Radioactive decay"
                        }
                    ], 
                    "description": "Videos on chemistry (roughly covering a first-year high school or college course).", 
                    "id": "chemistry", 
                    "title": "Chemistry"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "In this tutorial, Jay reminds you how to draw the dot structures of simple organic molecules.", 
                                    "id": "dot-strcutures-jay", 
                                    "title": "Dot structures"
                                }, 
                                {
                                    "description": "It's the liger of orbitals and essential to organic chemistry! In this tutorial, Sal discusses the hybridization of orbitals.", 
                                    "id": "hybridization", 
                                    "title": "Hybridization"
                                }, 
                                {
                                    "description": "In this tutorial, Jay goes over sp3, sp2, and sp hybridization.", 
                                    "id": "hybrid-orbitals-jay", 
                                    "title": "Hybrid orbitals"
                                }, 
                                {
                                    "description": "What is the most important concept to understand in undergraduate organic chemistry?  Of course, it's electronegativity!  In this tutorial, Jay explains the concept of electronegativity and shows how it applies to polarity, intermolecular forces, and physical properties.", 
                                    "id": "electronegativity-polarity", 
                                    "title": "Electronegativity"
                                }
                            ], 
                            "description": "A review of hybrid orbitals, dot structures, electronegativity, and polarity", 
                            "id": "gen-chem-review", 
                            "title": "General chemistry review"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Call them Bonds. Covalent Bonds. Smart chemists need time to stir (and shake) their solutions. In this tutorial, Jay explains how chemists use bond-line structures as a form of organic shorthand to skip time-consuming carbon and hydrogen atoms labeling. Watch this tutorial so you too can be in the Dr. Know.", 
                                    "id": "bond-line-structures", 
                                    "title": "Bond-line structures"
                                }, 
                                {
                                    "description": "In this tutorial, Jay puts the \"fun\" back into recognizing functional groups.", 
                                    "id": "functional-groups", 
                                    "title": "Functional groups"
                                }, 
                                {
                                    "description": "Positive and negative charges are everywhere in orgo!  In this tutorial, Jay shows you how to assign formal charges to molecules and how to draw resonance structures.", 
                                    "id": "formal-charge-resonance", 
                                    "title": "Formal charge and resonance"
                                }, 
                                {
                                    "description": "LEO the Lion goes GERRRR!!!!  If that is all that you remember about redox from general chemistry, then this tutorial is for you!   Jay shows you how to assign oxidation states in organic molecules.", 
                                    "id": "oxidation-reduction-review", 
                                    "title": "Oxidation and reduction"
                                }, 
                                {
                                    "description": "Do you remember the basics of acid/base chemistry? In this tutorial, Jay reminds you of a few definitions, shows you how the stability of the conjugate base affects the acidity of the molecule, and demonstrates the importance of pKa values.", 
                                    "id": "acid-base-review", 
                                    "title": "Acid/base"
                                }
                            ], 
                            "description": "bond-line structures, functional groups, formal charges, resonance structures, oxidation and reduction, acid/base chemistry", 
                            "id": "organic-structures", 
                            "title": "Organic structures and acid/base"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "In this tutorial, Sal shows how to name alkanes.", 
                                    "id": "naming-alkanes", 
                                    "title": "Naming alkanes"
                                }, 
                                {
                                    "description": "In this tutorial, Sal draws Newman projections and also explains chair and boat conformations for cyclohexane.", 
                                    "id": "conformations", 
                                    "title": "Conformations"
                                }, 
                                {
                                    "description": "Do you speak the language of organic chemistry?  In this tutorial, Jay shows you how to be fluent in naming alkanes, cycloalkanes, and bicyclic compounds.", 
                                    "id": "naming-alkanes-cycloalkanes-bicyclic", 
                                    "title": "Naming alkanes, cycloalkanes, and bicyclic compounds"
                                }, 
                                {
                                    "description": "In this tutorial, Jay shows the different conformations of straight chain alkanes and cyclohexane.", 
                                    "id": "conformations-alkanes-cycloalkanes", 
                                    "title": "Conformations of alkanes and cycloalkanes"
                                }, 
                                {
                                    "description": "In this tutorial, Sal introduces free radical reactions by showing the reaction of methane with chlorine.", 
                                    "id": "free-radical-reaction-alkanes", 
                                    "title": "Free radical reaction"
                                }
                            ], 
                            "description": "naming alkanes and cycloalkanes, conformations of alkanes and cycloalkanes, and free radical reactions", 
                            "id": "bond-line-structures-alkanes-cycloalkanes", 
                            "title": "Alkanes and cycloalkanes"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Are you right handed or sinister-handed?  Have you ever thought that you might not be as attractive as you look in the mirror?  Welcome to the world of chirality.\n\nIn this tutorial, Sal explores molecules that have the same composition and bonding, but are fundamentally different because they are mirror images of each other (kind of like Tomax and Xamot--the Crimson Guard Commanders from GI Joe).", 
                                    "id": "chirality-r-s-system", 
                                    "title": "Chirality and the R,S system"
                                }, 
                                {
                                    "description": "Mirror, mirror on the wall . . . who is the fairest stereoisomer of all?  In this tutorial, Jay explains chirality and how to determine the absolute configuration at a chirality center.", 
                                    "id": "chirality-absolute-configuration", 
                                    "title": "Chirality and absolute configuration"
                                }, 
                                {
                                    "description": "In this tutorial, Jay explains the concept of optical activity and demonstrates how to calculate specific rotation and enantiomeric excess.", 
                                    "id": "optical-activity", 
                                    "title": "Optical activity"
                                }, 
                                {
                                    "description": "In this tutorial, Sal and Jay define stereoisomers, diastereomers, and meso compounds.", 
                                    "id": "diastereomers-meso-compounds", 
                                    "title": "Diastereomers and meso compounds"
                                }
                            ], 
                            "description": "chirality, stereoisomers, assigning absolute configuration using the R,S system, optical activity, diastereomers, meso compounds", 
                            "id": "stereochemistry-topic", 
                            "title": "Stereochemistry"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "In this tutorial, Sal analyzes the differences between SN1 and SN2 reactions.", 
                                    "id": "sn1-sn2-sal", 
                                    "title": "Sn1 vs Sn2"
                                }, 
                                {
                                    "description": "In this tutorial, Sal discusses the difference between nucleophilicity and basicity.", 
                                    "id": "nucleophilicity-basicity-sal", 
                                    "title": "Nucleophilicity and basicity"
                                }, 
                                {
                                    "description": "In this tutorial, Sal explains the difference between an E1 and an E2 elimination reaction.", 
                                    "id": "elimination-reactions-tutorial", 
                                    "title": "Elimination reactions"
                                }, 
                                {
                                    "description": "In this tutorial, Sal compares the differences between SN1, SN2, E1, and E2 reactions.", 
                                    "id": "sn1-sn2-e1-e2-sal", 
                                    "title": "Sn1/Sn2/E1/E2"
                                }, 
                                {
                                    "description": "In this tutorial, Jay covers the definitions of nucleophile/electrophile, The Schwartz Rules (may the Schwartz be with you!), and the differences between SN1 and SN2 reactions.", 
                                    "id": "sn1-sn2-tutorial", 
                                    "title": "Sn1 and Sn2"
                                }, 
                                {
                                    "description": "In this tutorial, Jay covers the E1 elimination mechanism, carbocation rearrangements, and the details of the E2 elimination reaction.", 
                                    "id": "e1-e2-tutorial", 
                                    "title": "E1 and E2 reactions"
                                }, 
                                {
                                    "description": "In this tutorial, Jay discusses the strength of a nucleophile and the differences between SN1, SN2, E1, and E2 reactions.", 
                                    "id": "sn1-sn2-e1-e2-jay", 
                                    "title": "Sn1/Sn2/E1/E2"
                                }
                            ], 
                            "description": "SN1, SN2, E1, E2, nucleophiles, nucleophilicity, basicity", 
                            "id": "substitution-elimination-reactions", 
                            "title": "Substitution and elimination reactions"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "In this tutorial, Sal names alkenes and discusses the E-Z system.", 
                                    "id": "naming-alkenes", 
                                    "title": "Naming alkenes"
                                }, 
                                {
                                    "description": "In this tutorial, Sal shows several reactions of alkenes.", 
                                    "id": "alkene-reactions", 
                                    "title": "Alkene reactions"
                                }, 
                                {
                                    "description": "In this tutorial, Jay names alkenes, discusses the stability of alkenes, and introduces the E/Z system.", 
                                    "id": "naming-alkenes-jay", 
                                    "title": "Alkene nomenclature"
                                }, 
                                {
                                    "description": "In this tutorial, Jay explains the addition reactions of alkenes.", 
                                    "id": "alkene-reactions-tutorial", 
                                    "title": "Alkene reactions"
                                }, 
                                {
                                    "description": "In this tutorial, Jay covers the nomenclature and preparation of alkynes, the acidity of terminal alkynes, and the alkylation of alkynes.", 
                                    "id": "naming-preparation-alkynes", 
                                    "title": "Naming and preparing alkynes"
                                }, 
                                {
                                    "description": "In this tutorial, Jay shows the reactions of alkynes.", 
                                    "id": "alkyne-reactions", 
                                    "title": "Alkyne reactions"
                                }, 
                                {
                                    "description": "In this tutorial, Jay demonstrates how to use Dr. Schwartz's organic flowsheet to solve synthesis problems involving alkynes.  Always remember, pain is temporary, orgo is forever!", 
                                    "id": "synthesis-alkynes", 
                                    "title": "Synthesis using alkynes"
                                }
                            ], 
                            "description": "naming alkenes and alkynes, reactions of alkenes and alkynes, synthesis", 
                            "id": "alkenes-alkynes", 
                            "title": "Alkenes and alkynes"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "It can clean a wound or kill your liver.  Some religions ban it, others use it in their sacred rites.  Some of the most stupid acts humanity every committed were done under its influence.  It is even responsible for some of our births.   \n\nIn this tutorial, Sal and Jay name alcohols and discuss their properties.", 
                                    "id": "alcohol-nomenclature-properties", 
                                    "title": "Alcohol nomenclature and properties"
                                }, 
                                {
                                    "description": "In this tutorial, Jay shows how to synthesize alcohols using sodium borohydride, lithium aluminum hydride, and grignard reagents.", 
                                    "id": "synthesis-alcohols-tutorial", 
                                    "title": "Synthesis of alcohols"
                                }, 
                                {
                                    "description": "In this tutorial, Jay assigns oxidation states to alcohols, shows an oxidation mechanism using the Jones reagent, shows the formation of nitrate esters from alcohols, and demonstrates how to make alkyl halides from alcohols.  Biochemical redox reactions are also discussed.", 
                                    "id": "reactions-alcohols-tutorial", 
                                    "title": "Reactions of alcohols"
                                }, 
                                {
                                    "description": "In this tutorial, Sal and Jay name ethers and discuss the physical properties of ethers.", 
                                    "id": "nomenclature-properties-ethers", 
                                    "title": "Nomenclature and properties of ethers"
                                }, 
                                {
                                    "description": "In this tutorial, Jay shows how to synthesize ethers using the Williamson ether synthesis and how to cleave an ether linkage using acid.", 
                                    "id": "synthesis-cleavage-ethers", 
                                    "title": "Synthesis and cleavage of ethers"
                                }, 
                                {
                                    "description": "In this tutorial, Sal and Jay name epoxides.  Jay also shows the preparation of epoxides and includes the stereochemistry of the reaction.", 
                                    "id": "nomenclature-preparation-epoxides", 
                                    "title": "Nomenclature and preparation of epoxides"
                                }, 
                                {
                                    "description": "In this tutorial, Sal and Jay show the SN1 and SN2 ring opening reactions of epoxides.", 
                                    "id": "ring-opening-reactions-epoxides", 
                                    "title": "Ring-opening reactions of epoxides"
                                }, 
                                {
                                    "description": "In this tutorial, Jay shows how to prepare sulfides from thiols.", 
                                    "id": "thiols-sulfides", 
                                    "title": "Thiols and sulfides"
                                }
                            ], 
                            "description": "alcohols, ethers, epoxides, thiols, sulfides", 
                            "id": "alcohols-ethers-epoxides-sulfides", 
                            "title": "Alcohols, ethers, epoxides, sulfides"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "In this tutorial, Jay shows the possible products for an addition to a conjugated diene and how the end product can be controlled by changing the reaction conditions.", 
                                    "id": "addition-reactions-conjugated-dienes", 
                                    "title": "Addition reactions of conjugated dienes"
                                }, 
                                {
                                    "description": "In this tutorial, Jay shows the mechanism, stereochemistry, and regiochemistry for the classic Diels-Alder reaction.", 
                                    "id": "diels-alder-reaction", 
                                    "title": "Diels-Alder reaction"
                                }, 
                                {
                                    "description": "In this tutorial, Jay introduces molecular orbital (MO) theory and shows how MO theory explains the experimental observations of the Diels-Alder reaction.", 
                                    "id": "molecular-orbital-theory", 
                                    "title": "Molecular orbital theory"
                                }
                            ], 
                            "description": "conjugation, conjugated dienes, addition reactions of conjugated dienes, diels-alder reaction, MO theory, color", 
                            "id": "conjugation-diels-alder-mo-theory", 
                            "title": "Conjugation, Diels-Alder, and MO theory"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Would a cyclohexatriene by any other name smell as sweet? In this tutorial, Sal and Jay explain how to name benzene derivatives, the sometimes sweet-smelling cyclic molecules that can be used in the synthesis of explosives and plastics.", 
                                    "id": "naming-aromatic", 
                                    "title": "Naming benzene derivatives"
                                }, 
                                {
                                    "description": "In this tutorial, Sal shows the mechanism of Electrophilic Aromatic Substitution and the reactions of bromination and Friedel-Crafts Acylation.", 
                                    "id": "reactions-benzene", 
                                    "title": "Reactions of benzene"
                                }, 
                                {
                                    "description": "In this tutorial, Sal and Jay explain the concept of aromatic stabilization and show how to determine if a compound or an ion exhibits aromaticity.  Knowledge of MO theory is assumed.", 
                                    "id": "aromatic-stability", 
                                    "title": "Aromatic stability"
                                }, 
                                {
                                    "description": "In this tutorial, Jay shows several electrophilic aromatic substitution reactions.", 
                                    "id": "electrophilic-aromatic-substitution", 
                                    "title": "Electrophilic aromatic substitution"
                                }, 
                                {
                                    "description": "In this tutorial, Jay shows you the directing effects of substituents on a benzene ring. Knowledge of Electrophilic Aromatic Substitution reactions is assumed.   ", 
                                    "id": "deffect-2013-07-03T14:44:54.851Z", 
                                    "title": "Directing effects"
                                }, 
                                {
                                    "description": "In this tutorial, Jay covers a few more reactions of benzene derivatives and also shows how to approach the synthesis of substituted benzene rings.", 
                                    "id": "other-reactions-and-synthesis", 
                                    "title": "Other reactions and synthesis"
                                }, 
                                {
                                    "description": "In this tutorial, Jay shows the addition-elimination mechanism and the elimination-addition mechanism.", 
                                    "id": "nucleophilic-aromatic-substitution", 
                                    "title": "Nucleophilic aromatic substitution"
                                }
                            ], 
                            "description": "aromatic compounds, naming derivatives of benzene, electrophilic aromatic substitution reactions", 
                            "id": "aromatic-compounds", 
                            "title": "Aromatic compounds"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "In this tutorial, Sal and Jay show you the nomenclature, physical properties, and reactivity of aldehydes and ketones.", 
                                    "id": "nomenclature-aldehyde-ketone", 
                                    "title": "Introduction to aldehydes and ketones"
                                }, 
                                {
                                    "description": "In this tutorial, Jay shows you how to predict the products of the reactions of aldehydes and ketones.  ", 
                                    "id": "reactions-aldehydes-ketones-jay", 
                                    "title": "Reactions of aldehydes and ketones"
                                }
                            ], 
                            "description": "nomenclature and reactions of aldehydes and ketones", 
                            "id": "aldehydes-ketones", 
                            "title": "Aldehydes and ketones"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "In this tutorial, Sal shows how to name carboxylic acids.", 
                                    "id": "naming-carboxylic-acids-sal", 
                                    "title": "Naming carboxylic acids"
                                }, 
                                {
                                    "description": "In this tutorial, Sal shows the formation of carboxylic acid derivatives including esters, acyl chlorides, and amides.", 
                                    "id": "formation-carboxylic-acid-derivatives-sal", 
                                    "title": "Formation of carboxylic acid derivatives"
                                }, 
                                {
                                    "description": "In this tutorial, Jay shows you how to name carboxylic acids and the products of different reactions of carboxylic acids.  ", 
                                    "id": "reactions-carboxylic-jay", 
                                    "title": "Nomenclature and reactions of carboxylic acids"
                                }, 
                                {
                                    "description": "In this tutorial, Jay shows you the nomenclature, properties, and reactions of carboxylic acid derivatives.  ", 
                                    "id": "acid-derivatives-jay", 
                                    "title": "Nomenclature and reactions of carboxylic acid derivatives"
                                }
                            ], 
                            "description": "naming carboxylic acids, formation of carboxylic acid derivatives", 
                            "id": "carboxylic-acids-derivatives", 
                            "title": "Carboxylic acids and derivatives"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "In this tutorial, Sal and Jay show you how to form enolate anions from aldehydes and ketones.  ", 
                                    "id": "formation-of-enolate-anions", 
                                    "title": "Formation of enolate anions"
                                }, 
                                {
                                    "description": "In this tutorial, Sal and Jay show you the mechanism of the aldol condensation and how to predict the products of aldol reactions.  ", 
                                    "id": "aldol-condensation-jay", 
                                    "title": "Aldol condensations"
                                }
                            ], 
                            "description": "formation of enolate anions, aldol condensations", 
                            "id": "new-topic-2014-06-13T19:24:28.593Z", 
                            "title": "Alpha carbon chemistry"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "In this tutorial, Sal shows how to name amines.", 
                                    "id": "naming-amines", 
                                    "title": "Naming amines"
                                }
                            ], 
                            "description": "nomenclature and reactions of amines", 
                            "id": "amines-topic", 
                            "title": "Amines"
                        }
                    ], 
                    "description": "Sal and Jay cover topics covered in college organic chemistry course.  Basic understanding of basic high school or college chemistry assumed (although there is some review).", 
                    "id": "organic-chemistry", 
                    "title": "Organic chemistry"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "We humans have trouble comprehending something larger than, say, our planet (and even that isn't easy to conceptualize) and smaller than, say, a cell (once again, still not easy to think about).  This tutorial explores the scales of the universe well beyond that of normal human comprehension, but does so in a way that makes them at least a little more understandable. \n\nHow does a bacteria compare to an atom?  What about a galaxy to a star?  Turn on your inertial dampeners.  You're in store for quite a ride!", 
                                    "id": "scale-small-large-tutorial", 
                                    "title": "Scale of the small and large"
                                }, 
                                {
                                    "description": "This tutorial gives an overview of light and the fundamental four forces.  You won't have a degree in physics after this, but it'll give you some good context for understanding cosmology and the universe we are experiencing.  It should be pretty understandable by someone with a very basic background in science.", 
                                    "id": "light-fundamental-forces", 
                                    "title": "Light and fundamental forces"
                                }, 
                                {
                                    "description": "The Earth is huge, but it is tiny compared to the Sun (which is super huge). But the Sun is tiny compared to the solar system which is tiny compared to the distance to the next star.  Oh, did we mention that there are over 100 billion stars in our galaxy (which is about 100,000 light years in diameter) which is one of hundreds of billions of galaxies in just the observable universe (which might be infinite for all we know).  Don't feel small.  We find it liberating.  Your everyday human stresses are nothing compared to this enormity that we are a part of.  Enjoy the fact that we get to be part of this vastness!", 
                                    "id": "scale-earth-galaxy-tutorial", 
                                    "title": "Scale of earth, sun, galaxy and universe"
                                }, 
                                {
                                    "description": "Not only is the universe unimaginable large (possibly infinite), but it is also unimaginably old.  If you were feeling small in space, wait until you realize that all of human history is but a tiny blip in the history of the universe.", 
                                    "id": "cosmos-time-scale-tutorial", 
                                    "title": "Time scale of the cosmos"
                                }, 
                                {
                                    "description": "What does it mean for the universe to expand?  Was the \"big bang\" an explosion of some sort or a rapid expansion of space-time (it was the latter)?  If the universe was/is expanding, what is \"outside\" it?  How do we know how far/old things are?\n\nThis tutorial addresses some of the oldest questions known to man.", 
                                    "id": "big-bang-expansion-topic", 
                                    "title": "Big bang and expansion of the universe"
                                }
                            ], 
                            "description": "Things in our universe can be unimaginably large and small.  In this topic, we'll try to imagine the unimaginable!", 
                            "id": "universe-scale-topic", 
                            "title": "Scale of the universe"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Stars begin when material drifting in space condenses due to gravity to be dense enough for fusion to occur.  Depending on the volume and make-up of this material, the star could then develop into very different things--from supernovae, to neutron stars, to black holes. \n\nThis tutorial explores the life of stars and will have you appreciating the grand weirdness of our reality.", 
                                    "id": "stellar-life-death-tutorial", 
                                    "title": "Life and death of stars"
                                }, 
                                {
                                    "description": "Quasars are the brightest objects in the universe.  The gamma rays from them could sterilize a solar system (i.e. obliterate life).  What do we think these objects are?  Why don't we see any close by (which we should be thankful for)?  Could they tell us what our own galaxy may have been like 1 billion or so years ago?", 
                                    "id": "quasars", 
                                    "title": "Quasars and galactive collisions"
                                }, 
                                {
                                    "description": "We've talked a lot about distances to stars, but how do we know?  Stellar parallax--which looks at how much a star shifts  in the sky when Earth is at various points in its orbit--is the oldest technique we have for measuring how far stars are.\n\nIt is great for \"nearby\" stars even with precise instruments (i.e, in our part of our galaxy).  To measure distance further, we have to start thinking about Cepheid variables (other tutorial).", 
                                    "id": "stellar-parallax-tutorial", 
                                    "title": "Stellar parallax"
                                }, 
                                {
                                    "description": "Stellar parallax can be used for \"nearby\" stars, but what if we want to measure further out?  Well this tutorial will expose you to a class of stars that helps us do this.  Cepheids are large, bright, variable stars that are visible in  other galaxies.  We know how bright they should be and can gauge how far they are by how bright they look to us.", 
                                    "id": "cepheid-variables", 
                                    "title": "Cepheid variables"
                                }
                            ], 
                            "description": "Our universe is defined by stars.  This topic explores how they came to be and where they end up.  This includes a discussion of black holes and galaxies.", 
                            "id": "stellar-life-topic", 
                            "title": "Stars, black holes and galaxies"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Is it a coincidence that Africa and South America could fit like puzzle pieces?  Why do earthquakes happen where they do?  What about volcanoes and mountains?  Are all of these ideas linked?  Yes, they are.\n\nThis tutorial on plate-tectonics explains how and why the continents have shifted over time.  In the process, we also explore the structure of the Earth, all the way down to the core.", 
                                    "id": "plate-techtonics", 
                                    "title": "Plate tectonics"
                                }, 
                                {
                                    "description": "How do we know what the Earth is made up of?  Has someone dug to the core?  No, but we humans have been able to see how earthquake (seismic) waves have been bent and reflected through our planet to get a reasonable idea of what is down there.", 
                                    "id": "seismic-waves-tutorial", 
                                    "title": "Seismic waves and how we know earth's structure"
                                }, 
                                {
                                    "description": "What causes the seasons?  Even more, can Earth's climate change over long period just to \"wobbles\" in its orbit?  This tutorial explains it all.  You'll know more about orbits (and precession and Milankovitch cycles) than you ever thought possible.  Have fun!", 
                                    "id": "earth-title-topic", 
                                    "title": "Earth's rotation and tilt"
                                }
                            ], 
                            "description": "What is the Earth made up of and how do we know?  What causes the seasons?  Are there longer-ranging cycles in Earth's climate?", 
                            "id": "earth-history-topic", 
                            "title": "Earth geological and climatic history"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Earth is over 4.5 billion years old.  How do we know this?  When did life first emerge?  \n\nFrom the dawn of Earth as a planet to the first primitive life forms to our \"modern\" species, this tutorial is an epic journey of the history of life on Earth.", 
                                    "id": "history-life-earth-tutorial", 
                                    "title": "History of life on earth"
                                }, 
                                {
                                    "description": "Where do we think humans come from?  How and why have we developed as a species.  This tutorial attempts to give an overview of these truly fundamental questions.\n\nFrom human evolution (which is covered in more depth in the biology playlist) to the development of agriculture, this tutorial will give you an appreciation of where we've been (and maybe where we're going).", 
                                    "id": "humanity-on-earth-tutorial", 
                                    "title": "Humanity on earth"
                                }, 
                                {
                                    "description": "Geologists and archaeologists will tell you how old things are or when they happened, but how do they know?  This tutorial answers this question by covering some of the primary techniques of \"dating\" (not in the romantic sense).", 
                                    "id": "measuring-age-tutorial", 
                                    "title": "Measuring age on earth"
                                }, 
                                {
                                    "description": "Are dolphins the only intelligent life in the universe?  We don't know for sure, but this tutorial gives a framework for thinking about the problem.", 
                                    "id": "life-in-universe-topic", 
                                    "title": "Life in the universe"
                                }
                            ], 
                            "description": "When and how did life emerge on Earth?  How did humanity develop a civilization?  Is there other intelligent life out there?", 
                            "id": "life-earth-universe", 
                            "title": "Life on earth and in the universe"
                        }
                    ], 
                    "description": "Videos attempting to grasp a little bit about our Universe (many of the topics associated with \"Big History\")", 
                    "id": "cosmology-and-astronomy", 
                    "title": "Cosmology and astronomy"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "No organ quite symbolizes love like the heart.  One reason may be that your heart helps you live, by moving ~5 liters (1.3 gallons) of blood through almost 100,000 kilometers (62,000 miles) of blood vessels every single minute!  It has to do this all day, everyday, without ever taking a vacation!  Now that is true love.  Learn about how the heart works, how blood flows through the heart, where the blood goes after it leaves the heart, and what your heart is doing when it makes the sound \u201cLub Dub\u201d.", 
                                    "id": "heart-introduction", 
                                    "title": "Heart introduction"
                                }, 
                                {
                                    "description": "Where does your blood go after it leaves the heart? Your body has a fantastic pipeline system that moves your blood around to drop off oxygen and food to those hungry cells, and removes cell waste. Learn how arteries carry blood away from the heart, how veins bring blood back to the heart, and about the different layers of cells that make up these blood vessels.", 
                                    "id": "blood-vessels", 
                                    "title": "Blood vessels"
                                }, 
                                {
                                    "description": "Using the stethoscope to check blood pressure is a technique that\u2019s been used for >100 years!  Blood pressure is one of the major vital signs frequently measured by health care workers, and it tells us a lot about our blood circulation.  Learn what blood pressure is, how it relates to resistance in a tube, why it is necessary to get oxygen to your cells, and how it can change as you age.  We\u2019ll finally put it all together by relating pressure, flow, and resistance in one awesome equation!", 
                                    "id": "blood_pressure", 
                                    "title": "Blood pressure"
                                }, 
                                {
                                    "description": "Welcome to the lymphatic system! Learn about how it is a critical part of the circulatory system. Find out how it comes to the rescue of the cardiovascular system and the immune system. Also discover how it moves fluid in one direction, like blood, but without a heart!", 
                                    "id": "lymphatics", 
                                    "title": "Lymphatics"
                                }, 
                                {
                                    "description": "At one stage or another in development, every friend you know had gill slits and a tail.  Pretty crazy thought, huh?  Fetal development is incredible, and it\u2019s important to understand exactly how it happens. The structure and function of the circulatory system is incredibly complex, and fetuses are no exception. Find out how the heart and circulatory system work in the fetus!", 
                                    "id": "fetal-circulation", 
                                    "title": "Fetal circulation"
                                }, 
                                {
                                    "description": "The human body enjoys stability. For example, if your blood pressure changes, the body puts a couple of brilliant systems into motion in order to respond and bring your blood pressure back to normal.  There are some quick responses using nerves and some slower responses using hormones.  The system using hormones is sometimes called the renin-angiotensin-aldosterone-system (RAAS), which is the main system in the body for controlling blood pressure. When your blood pressure drops too low or gets too high, your kidneys, liver, and pituitary gland (part of your brain) talk to each other to solve the problem. They do this without you even noticing! Learn how the body knows when the blood pressure has changed, and how hormones like angiotensin 2, aldosterone, and ADH help return blood pressure to back to normal.", 
                                    "id": "blood_pressure_control", 
                                    "title": "Blood pressure control"
                                }, 
                                {
                                    "description": "Believe it or not, the arteries are elastic and when they recoil they actually push blood along when the heart is relaxing (diastole).  This is known as the windkessel effect and is the same basic principle used by some water guns.  Unfortunately, with all the work that the circulatory system has to do, our arteries can become rigid with age. When the arteries get stiff like lead pipes, the problem is quite different then when the arteries actually get clogged up, but just as important.", 
                                    "id": "arterial-stiffness", 
                                    "title": "Arterial stiffness"
                                }, 
                                {
                                    "description": "Your heart is made of a special type of muscle, found nowhere else in the body! This unique muscle is specialized to perform the repetitive task of pumping your blood throughout your body, from the day you\u2019re born to the day you die. We\u2019ll take an in-depth look of how the heart accomplishes this on a cellular level, and learn about the proteins actin and myosin that are the workhorses that tug and pull on one another to create every single muscle contraction. You\u2019ll appreciate the fact that your heart beat is a fairly sophisticated process!", 
                                    "id": "heart-muscle-contraction", 
                                    "title": "Heart muscle contraction"
                                }, 
                                {
                                    "description": "Your heart relies on the flow of electricity to maintain a steady, consistent beat - like an automatic pump that maintains a regular rate and rhythm throughout your life! There are specialized heart cells that allow positive current to travel quickly throughout the heart muscle. In these videos, we\u2019ll check out the flow of this positive charge on a macroscopic and microscopic level.", 
                                    "id": "heart-depolarization", 
                                    "title": "Heart depolarization"
                                }, 
                                {
                                    "description": "Although your heart can beat independently, your nervous system is important as an external regulator. Your brain can tell your heart to speed up or slow down, depending on the scenario. For example, when you\u2019re falling asleep, your nervous system will cause your heart to slow down, and 8 hours later when your phone alarm goes off, your nervous system will speed up your heartbeat!  So even though your heart muscle beats by itself, the nerves can ramp up or down the speed.  Check out the videos to learn more about how the nerves help to regulate the heart.", 
                                    "id": "nerve-regulation-of-the-heart", 
                                    "title": "Nerve regulation of the heart"
                                }, 
                                {
                                    "description": "After using your jeans for a while, you\u2019ll begin to notice small tears and rips developing in the fabric. Why doesn\u2019t this happen to your heart as well? Well, your heart manages to stay healthy despite all of the \u201cwall stress\u201d that pulls on the heart walls. During different parts of the heart cycle (afterload vs. preload) the mechanics of \u201cwall stress\u201d change dramatically.  Learn exactly what preload and afterload mean, and how we can use pressure-volume loops to estimate their values.", 
                                    "id": "preload-and-afterload", 
                                    "title": "Preload and afterload"
                                }, 
                                {
                                    "description": "Once you\u2019ve learned about the PV loop, a natural question arises - Does it ever change shape?  It turns out that there are precisely three things that can change the shape of the loop: 1. Preload, 2. Afterload, and 3. Contractility.  That\u2019s it!  The tricky part comes when you try to change one and you realize that the body begins to change the other two as well as a natural consequence.  In order to simplify, you\u2019ll find that PV loops are sometimes even described as PV boxes.  You\u2019ll get to learn about PV loops, PV boxes, and even play around with them yourself in this tutorial!", 
                                    "id": "changing-the-PV-loop", 
                                    "title": "Changing the PV loop"
                                }, 
                                {
                                    "description": "The pressure volume loop is one of the classic figures that helps us to conceptualize and understand the mechanics of the left ventricle of the heart.  In addition to a filling up with blood and squeezing out blood there is a (very short) period of time when the heart muscle is contracting and relaxing with no volume change! As the left ventricle moves around the PV loop with each lub dub you get a sense for the amazing amount of work it does as pressures and volumes go up and down, all day, every day.  This is a fascinating area where physics and biology meet to produce something miraculous.", 
                                    "id": "pressure-volume-loops", 
                                    "title": "Pressure volume loops"
                                }
                            ], 
                            "description": "Your heart sits in the middle of your chest and pumps blood from about 4 weeks after conception until the day that you die.  It never stops, and over your lifetime it will pump ~175 million liters of blood.  To visualize that, imagine the amount of water that falls over Niagara falls in a few minutes.  Remarkable!  This little pump is the size of your clenched fist and in an adult can weigh about 300 grams.  Watch these videos to learn more about how the heart works, blood flow in arteries and veins, blood pressure, and lymphatics.", 
                            "id": "circulatory-system", 
                            "title": "Circulatory system"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Heart disease is the number one cause of death globally (~30% of all deaths!). It affects different parts of the world unequally, with the majority of deaths occurring in low-income or middle-income countries. Find out what heart disease and stroke are, what can cause them, and how the two are related!", 
                                    "id": "heart-disease-and-stroke", 
                                    "title": "Heart disease and stroke"
                                }, 
                                {
                                    "description": "The ancient Greeks thought blood vessels actually carried air throughout the body. Although we know better today, many people are still often confused with the specifics! We now know that the vessels carry blood instead, and we are able to distinguish between two different types: arteries and veins. Learn about how arteries differ from veins and how vessels can get damaged over time.", 
                                    "id": "blood-vessel-diseases", 
                                    "title": "Blood vessel diseases"
                                }, 
                                {
                                    "description": "Nearly one billion people in the world have high blood pressure. That\u2019s 1 in every 7 people! With the amount of unhealthy foods becoming increasingly available to everyone, it makes sense that this number is climbing. This set of videos will explore high blood pressure, also known as hypertension. Learn more about it, what it does to different parts of the body, symptoms of hypertension, and what you can do with your everyday life to manage it!", 
                                    "id": "hypertension", 
                                    "title": "Hypertension"
                                }, 
                                {
                                    "description": "", 
                                    "id": "dysrhythmias-and-tachycardias", 
                                    "title": "Cardiac dysrhythmias and tachycardias"
                                }, 
                                {
                                    "description": "", 
                                    "id": "acyanotic-heart-diseases", 
                                    "title": "Acyanotic heart diseases"
                                }, 
                                {
                                    "description": "", 
                                    "id": "vasculitis", 
                                    "title": "Vasculitis"
                                }
                            ], 
                            "description": "With the heart pumping 24 hours a day, 7 days a week, it\u2019s absolutely vital to make sure things are flowing smoothly (pun intended!). Unfortunately, this isn\u2019t always the case, and different parts of the circulatory system can cause problems: your heart, your blood vessels, and even the fluid in your tissues and blood itself can be the issue.  To further complicate things, the underlying reasons for circulatory system problems vary from your genes (nature) to your lifestyle habits (nurture). An understanding of how different diseases can affect your circulatory system is important to combat this growing problem in the world.", 
                            "id": "circulatory-system-diseases", 
                            "title": "Circulatory system diseases"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Did you know that your right lung is larger than your left? That\u2019s because the majority of your heart is on the left side of your body, and your left lung is slightly smaller to accommodate it! The lungs take in oxygen and help you breathe out carbon dioxide.  Humans have an intricate respiratory system, with hundreds of millions of  tiny air sacs called alveoli, where all of the magic happens.  These videos will introduce you to the lungs, and show how they help you sing and survive!", 
                                    "id": "lung_introduction", 
                                    "title": "Lung introduction"
                                }, 
                                {
                                    "description": "If you think of your lungs as a mini factory, you can think of the gases as goods that your body trades. Humans need oxygen for important metabolic activities. For example, when you exercise, your breathe more because your body needs more oxygen! These metabolic activities produce carbon dioxide, which is something your body needs to get rid of to avoid blood acidity. So, keeping with the example of your lungs as a factory, oxygen is an import good, and carbon dioxide is an export good! Learn more about the specific mechanisms of this \u201cgoods exchange\u201d in the tiny air sacs of the lungs: the alveoli.", 
                                    "id": "gas_exchange", 
                                    "title": "Gas exchange"
                                }, 
                                {
                                    "description": "Luckily, we can breathe without thinking which means that we have autonomic control of breathing. If we couldn\u2019t, we would risk dying if we went to sleep (look up Ondine\u2019s curse)! There are times when the body wants more oxygen (like during heavy exercise), and when the body wants less (like when we\u2019re resting). How does our body automatically seem to know when to inhale more, and when to inhale less? Also, if we do have autonomic control of breathing, how is it possible to also have conscious control of our breathing?  These questions get to the fundamentals of breathing control.", 
                                    "id": "breathing_control", 
                                    "title": "Breathing control"
                                }
                            ], 
                            "description": "Place your hand on your ribs and inhale deeply. You\u2019ll notice that your chest expands and your back straightens. As this occurs, air is rushing through your windpipe and branches off to either your left or right lung. After 20 to 30 more branch points, oxygen in the air ends up in the alveoli where it diffuses into the liquid that surrounds the alveoli, and slips into the blood.  This microscopic gas exchange occurs rapidly, oxygen is taken into the body and carbon dioxide is removed from the body, and then you exhale. Learn more about the intricate and fascinating respiratory system in these videos!", 
                            "id": "respiratory-system", 
                            "title": "Respiratory system"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "intro-to-pulmonary-diseases", 
                                    "title": "Introduction to pulmonary diseases"
                                }, 
                                {
                                    "description": "Most people have had the flu virus at least once in their lives, and it\u2019s usually not a pleasant experience\u2026  Fight back with some good information!  Learn about typical flu symptoms (and how tell it apart from the cold), and how the flu virus invades your cells to cause disease.  Finally, learn how flu vaccines may help prevent you from getting sick, and how we can test and treat the flu just in case you get really ill.  Stay healthy, my friends!", 
                                    "id": "influenza", 
                                    "title": "Influenza"
                                }, 
                                {
                                    "description": "Almost one third of the entire world\u2019s population is infected with Mycobacterium tuberculosis, the type of bacteria that causes TB. Although only a fraction of these people will actually become sick with the disease, in 2012, the World Health Organization reported 1.3 million TB related deaths. The good news is that health care workers and public health officials around the world have done a great job of helping to detect and treat the disease early.  The bad news is that TB is developing drug resistance.  Learn more about this ancient disease, that still plagues us in the modern-day.", 
                                    "id": "tuberculosis", 
                                    "title": "Tuberculosis"
                                }, 
                                {
                                    "description": "", 
                                    "id": "emphysema", 
                                    "title": "Emphysema (COPD)"
                                }, 
                                {
                                    "description": "", 
                                    "id": "chronic-bronchitis", 
                                    "title": "Chronic Bronchitis (COPD)"
                                }, 
                                {
                                    "description": "", 
                                    "id": "lung-cancer", 
                                    "title": "Lung cancer"
                                }, 
                                {
                                    "description": "", 
                                    "id": "pneumonia", 
                                    "title": "Pneumonia"
                                }, 
                                {
                                    "description": "", 
                                    "id": "pleural-effusion-2", 
                                    "title": "Pleural Effusion"
                                }
                            ], 
                            "description": "Our lungs are composed of a bronchial tree (think of an upside down tree with millions of leaves), blood vessels bringing blood in and out, and a protein-rich fluid that forms a matrix holding everything together!  If any part of this well-balanced organ isn\u2019t working properly, a person can be left feeling short of breath.  The lungs are also exposed to the outside environment, making them prone to infections.  To counter infections, the lungs are lined with cells that have tiny protein bristles which wave back and forth and can literally sweep away dangerous bacteria.  Learn more about diseases of the lungs and how modern medicine helps to keep them healthy!", 
                            "id": "respiratory-system-diseases", 
                            "title": "Respiratory system diseases"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "If you want to learn more about the renal system, then urine the right place! Take a minute and imagine a dirty pool filled with algae. Placing a filter in this pool will cause the algae to be flushed out and disposed of, and after a time you\u2019ll have a nice, clean, crispy blue pool to enjoy. Just like the filter for a pool, our kidneys filter our blood and remove toxic wastes from it. Humans have developed a system of disposing of this waste, while retaining nutrients and substances important to our well-being. \n\n\nOur kidneys play a vital role in maintaining homeostasis, or the physiological balance of the body. Every thirty minutes, our kidneys filter the entire supply of blood in our body. Unfortunately, they are also prone to disease, which is illustrated by the fact that 1 in every 9 American adults currently has a kidney disease. Additionally, more than 82% of Americans waiting for a life-saving organ transplant is waiting for a kidney, but only 17% of these patients get one each year. \n\n\nIn this tutorial, learn how the kidneys take blood and very selectively extract waste from it to expel from the body as urine.\n", 
                                    "id": "Introduction-to-the-kidneys", 
                                    "title": "Introduction to the kidneys"
                                }
                            ], 
                            "description": "If you want to learn more about the renal system, then urine the right place! Take a minute and imagine a dirty pool filled with algae. Placing a filter in this pool will cause the algae to be flushed out and disposed of, and after a time you\u2019ll have a nice, clean, crispy blue pool to enjoy. Just like the filter for a pool, our kidneys filter our blood and remove toxic wastes from it. Humans have developed a system of disposing of this waste, while retaining nutrients and substances important to our well-being. \n\n\nOur kidneys play a vital role in maintaining homeostasis, or the physiological balance of the body. Every thirty minutes, our kidneys filter the entire supply of blood in our body. Unfortunately, they are also prone to disease, which is illustrated by the fact that 1 in every 9 American adults currently has a kidney disease. Additionally, more than 82% of Americans waiting for a life-saving organ transplant is waiting for a kidney, but only 17% of these patients get one each year. \n\n\nIn this tutorial, learn how the kidneys take blood and very selectively extract waste from it to expel from the body as urine.\n", 
                            "id": "renal-system", 
                            "title": "Renal system"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "3A: Get an overview of the structure and function of neurons, and learn about the many other important cells needed to help our nervous system function optimally!  By Matt Jensen.", 
                                    "id": "copy-of-neural-cells-2014-03-27T17:58:07.293Z", 
                                    "title": "Neural cells"
                                }, 
                                {
                                    "description": "Learn the causes and functions of neuron membrane potentials, including resting, graded, and action potentials.", 
                                    "id": "neuron-membrane-potentials-2014-03-27T17:58:17.207Z", 
                                    "title": "Neuron membrane potentials"
                                }, 
                                {
                                    "description": "An overview of how neurons communicate with their target cells at synapses, and the roles of neurotransmitters and their receptors.", 
                                    "id": "neural-synapses-2014-03-27T17:58:26.721Z", 
                                    "title": "Neuronal synapses"
                                }, 
                                {
                                    "description": "Learn about how we perceive our various senses, including the theories, laws, and organizational principles that underly our ability to make sense of the world around us.", 
                                    "id": "sensory-perception-2014-03-27T18:45:20.451Z", 
                                    "title": "Sensory perception"
                                }, 
                                {
                                    "description": "Photons are hitting your eye as you read this!  Learn about our sense of sight, including the cells responsible for converting light into a neural impulse, the structure of the eye, and how we break down images to make sense of them.", 
                                    "id": "sight-2014-03-27T18:45:34.237Z", 
                                    "title": "Sight (vision)"
                                }, 
                                {
                                    "description": "Learn about how we hear, including the structure of the outer, middle, and inner ear, as well as the basics of auditory processing & cochlear implants.", 
                                    "id": "sound-audition-2014-03-27T18:45:45.806Z", 
                                    "title": "Sound (Audition)"
                                }, 
                                {
                                    "description": "We perceive the environment through our bodily senses, including our sensation of pain, temperature, pressure, balance, and movement.  Discover how our body gathers this information and processes it so that we can make sense of the world.", 
                                    "id": "somatosensation-2014-03-27T18:45:57.777Z", 
                                    "title": "Somatosensation"
                                }, 
                                {
                                    "description": "Learn about our senses of smell (olfaction) and taste (gustation), including the anatomy and underlying molecular basis behind these important senses.", 
                                    "id": "taste (gustation) and smell (olfaction)-2014-03-27T18:46:12.074Z", 
                                    "title": "Taste (gustation) and smell (olfaction)"
                                }
                            ], 
                            "description": "There are billions and billions of neurons in your brain (about 85 billion), and they\u2019re all sending electrical signals throughout your body right now! They tell your eyes to move across this page, how to interpret the words that you read, how to maintain your posture, your heart rate, and your breathing...all of it in a fraction of a second.  In this section, we\u2019ll explore the nature of this vast, complex system, from the cellular level to how it operates at a sensory level. A common misconception is that we only have 5 senses (see, smell, taste, hear, and feel), but we have many more that are nuanced but equally important. Learn more about how our bodies are designed to interact with the world.", 
                            "id": "nervous-system-and-sensory-infor", 
                            "title": "Nervous system and sensory information"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Explore cognitive development and intelligence, as well as how our minds solve problems, make decisions, and represent knowledge.", 
                                    "id": "cognition-2014-03-27T18:40:04.738Z", 
                                    "title": "Cognition"
                                }, 
                                {
                                    "description": "Have you ever tried to multi-task?  Explore the concept of selective and divided attention, as well as the role of language in cognition and development.", 
                                    "id": "attention-language-2014-03-27T18:40:12.306Z", 
                                    "title": "Attention and language"
                                }, 
                                {
                                    "description": "Explore states of consciousness, circadian rhythms, sleep stages, and sleep disorders.", 
                                    "id": "sleep-and-consciousness-2014-03-27T18:40:21.036Z", 
                                    "title": "Sleep and consciousness"
                                }, 
                                {
                                    "description": "Explore the structure of human memory; processes involved in normal encoding, retrieval, forgetting, and aging; and diseases affecting memory.", 
                                    "id": "memory-2014-03-27T18:40:29.837Z", 
                                    "title": "Memory"
                                }, 
                                {
                                    "description": "Learn about the physiological, behavioral, and cognitive components of emotion.  Appreciate how different areas of our brain play a role in emotion.  Understand the basic theories of emotion.", 
                                    "id": "emotion-2014-03-27T18:40:38.294Z", 
                                    "title": "Emotion"
                                }
                            ], 
                            "description": "Aristotle asserted that what separates humankind from non-human animals is our ability to engage in high reasoning. This reasoning includes solving problems, making decisions, recalling and recording memories, and expressing complex emotions. We\u2019ll explore different states of consciousness, and how our brain adapts and responds to stimuli. Learn all about the higher-order executive functions of the brain, which help you remember your friend\u2019s name, learn a new language, and even fall asleep at night.", 
                            "id": "executive systems of the brain", 
                            "title": "Executive systems of the brain"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "introduction-to-hematologic", 
                                    "title": "Introduction to hematologic system"
                                }, 
                                {
                                    "description": "", 
                                    "id": "bleeding-and-impaired-hemostasis", 
                                    "title": "Bleeding and impaired hemostasis"
                                }
                            ], 
                            "description": "It takes between 30 seconds to a minute for your blood to travel from your heart, to your body, and back to the heart again - perhaps a bit longer if the trip is out to your big toe! Our blood is incredibly important for transporting oxygen throughout the body. Hemoglobin, the protein that fills our blood cells, has wonderful mechanisms to allow it to bind to both oxygen and carbon dioxide. This is important for effective and quick transport of the gases around our body. Our blood is about 45% cells and 55% plasma, so the old adage \u201cblood is thicker than water\u201d quite literally holds true in scientific terms! Learn more about how this amazing system works in the following videos.", 
                            "id": "hematologic system", 
                            "title": "Hematologic system"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "anemia", 
                                    "title": "Anemia"
                                }, 
                                {
                                    "description": "", 
                                    "id": "leukemia", 
                                    "title": "Leukemia"
                                }
                            ], 
                            "description": "Blood is incredibly important in combating disease and the healing process after an injury. It acts as a highway for medicine, stops bleeding, fights infections, controls cells from multiplying too fast, and so much more. But things can go wrong with blood too! What if your blood couldn\u2019t clot and stop you from bleeding, or started to clot uncontrollably? What if your red blood cells or white blood cells suddenly disappeared? Blood contains many different types of tissues doing very different jobs, making diseases of the blood produce a variety of symptoms, including continuously feeling tired and bone pain. Learn about the different blood diseases, how they are diagnosed, and the cool ways health professionals treat these conditions.", 
                            "id": "hematologic system diseases", 
                            "title": "Hematologic system diseases"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Discover your body's arsenal of weapons against invaders, like bacteria and viruses. Find out which different kinds of cells are involved, and how they work.", 
                                    "id": "introduction-to-immunology", 
                                    "title": "Introduction to immunology"
                                }
                            ], 
                            "description": "Chances are, you\u2019ve had a fever or a cough at least once in your life (unless you live in a bubble, in which case go outside more!). Have you ever wondered why your body is reacting this way? It turns out humans have an entire arsenal of weapons against invaders, like bacteria and viruses. We have specialized cells that destroy various foreign bodies in a number of ways, including consumption, expulsion, and degradation. Learn how these little fighters are keeping you alive and healthy in this tutorial.", 
                            "id": "immune-system", 
                            "title": "Immune system"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "How do our muscles work? When we decide to kick a ball or shake a leg, how do we get our bodies to do that? Which muscles do we control? Which muscles control us? Learn how our muscles work at the smallest, most cellular level. Then see how nature scales up those microscopic processes into a kick or a dance move. Finally, learn how our brain tells muscle to contract and how that helps us respond to changes in temperature or even a lion chasing us.", 
                                    "id": "Introduction to muscles", 
                                    "title": "Introduction to muscles"
                                }, 
                                {
                                    "description": "The skeletal system plays numerous vital roles in the human body. Learn about the structure and function of bones and the skeleton, as well as the endocrine control of the skeletal system.", 
                                    "id": "skeletal-system", 
                                    "title": "Skeletal system"
                                }
                            ], 
                            "description": "Our muscles and bones keep us moving and form the basic physical structure for the rest of our organ systems. They also act as a sort of protective armor against physical damage. Muscles are connected to bones, and bones are connected (via ligaments) to other bones. In these videos, we\u2019ll go into how and why we have conscious control of our muscles, how our bones fit in with this control, how each of these components are connected, and much more. A fun fact: The largest muscle in your body is your gluteus maximus (your buttock!), and the bone most often broken is the collar bone!", 
                            "id": "musculoskeletal system", 
                            "title": "Musculoskeletal system"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "You might hear the word \u201chormone\u201d thrown around a lot. But what exactly is a hormone? And, more importantly, why should you care what a hormone is? Hormones are built from single amino acids, chains of amino acids (peptides), or cholesterol, and they are a form of chemical communication between cells.  Sometimes the signal is being sent a long distance, for example from the brain down to the bones in the toe, and other times the signal is being sent to cells that are just a few millimeters away. Either way, hormones allow important conversations to take place within the body.", 
                                    "id": "introduction to hormones", 
                                    "title": "Introduction to hormones"
                                }, 
                                {
                                    "description": "Consider any behavior, sleeping for instance, and think about all of the organs that have to work together to have it go smoothly.  The heart and lungs need to slow down, the brain needs to stop taking in the cues from the environment, and the bladder needs to wait until morning to empty.  This coordinated effort is achieved by a number of unique hormones acting on different tissues.  Learn more about how this process works and why it\u2019s so critical to our everyday lives!", 
                                    "id": "biological-basis-of-behavior-endocrine-system-2014-03-27T18:06:55.890Z", 
                                    "title": "Biological basis of behavior: Endocrine system"
                                }
                            ], 
                            "description": "When you\u2019re nervous before an important speech, or asking someone out on a date, you might feel butterflies in your stomach. This is actually the result of your endocrine system releasing hormones! You can\u2019t really point to any single organ as \u201cthe endocrine system\u201d, because it\u2019s actually a family of glands that secrete hormones into the body. Hormones seep into the blood (imagine putting a tea bag into hot water), and as the blood flows around the body, it carries with it these important hormone molecules that interact with specific target cells and organs.  This signaling system helps to keep the entire body well-balanced and on the same page.", 
                            "id": "endocrine system", 
                            "title": "Endocrine system"
                        }, 
                        {
                            "description": "Ever wonder about your lab values and what they mean? Lab values measure amounts of electrolytes or cells in your blood and occasionally tell you about how hormones and enzymes are working! Dive deeper and get a good understanding of concentrations as well!", 
                            "id": "lab-values", 
                            "title": "Lab values and concentrations"
                        }, 
                        {
                            "description": "In this section, we\u2019ll revisit the endocrine system. After a review, we\u2019ll explore how our hormones can cause different kinds of symptoms and behaviors, including normal childhood growth and precocious puberty (puberty kicking in at an earlier age than normal). After that, we\u2019ll take a closer look at diabetes, which is a growing endemic in the world as we see a greater availability of cheap, low quality foods. This will include a focus on glucose concentration and other blood sugar levels, and what your body (and modern medicine) can do to maintain a healthy balance in your body.", 
                            "id": "endocrinology-and-diabetes", 
                            "title": "Endocrinology and diabetes"
                        }, 
                        {
                            "description": "The colon, otherwise known as the \u201clarge intestine,\u201d is a tube that\u2019s about 5 feet long (1.5 meters). This is where the majority of fluid reabsorption occurs in your GI tract (the tract extending from your mouth to your anal sphincter). The colon is susceptible to multiple diseases, including hyperplasia, dysplasia, and cancer. Learn more about healthy colon tissue and these three diseases in the following videos. Join Sal and Dr. Andy Connolly as they (and you) take a microscopic look at colon tissue!", 
                            "id": "colon-disease", 
                            "title": "Colon disease"
                        }, 
                        {
                            "description": "Your cervical spine is the uppermost part of your spine, the part that makes up your neck. Take a look at the 7 vertebra that compose the cervical spine, and see different views of a real person\u2019s spine! Join Sal and Dr. Mahadevan as they inspect these X-rays and discuss its alignment and protection in airway management.", 
                            "id": "cervical-spine", 
                            "title": "Cervical spine"
                        }, 
                        {
                            "description": "If you looked at our \u201cCirculatory system diseases\u201d section, you already know that diseases related to an unhealthy lifestyle are on a critical rise. We hope that the following set of videos will allow you to develop a healthier lifestyle, and help you improve the lives of others as well. This is important for parents, children, students, and anyone who wants to take better care of their body.  Learn some of the fundamentals behind staying healthy: Reducing your salt, keeping your weight in a healthy range, and exercising regularly.", 
                            "id": "healthy-lifestyle", 
                            "title": "Healthy lifestyle"
                        }, 
                        {
                            "description": "The health care system in the United States is rapidly changing. To better understand these changes, we review the health care insurance, drug pricing, physician compensation, and much more! join us as we explore the basics about the Health Care system in the US, including a comparison with European healthcare.", 
                            "id": "health-care-system", 
                            "title": "Health care system"
                        }, 
                        {
                            "description": "Enjoy!", 
                            "id": "healthcare-misc", 
                            "title": "Miscellaneous"
                        }
                    ], 
                    "description": "The medical world can be a confusing place. Patients and their families might feel overwhelmed by the large vocabularies and complicated explanations they get from their health care providers. Students entering health care also struggle to grasp the complexity of health sciences, and are forced to memorize huge amounts of information. We hope to make understanding the medical world a bit easier. Look around!\n\nThese videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have\nregarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video.", 
                    "id": "health-and-medicine", 
                    "title": "Health and medicine"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "The discovery of magnetism. What can we do with this invisible force?", 
                                    "id": "magnetism", 
                                    "title": "Discovery of magnetism"
                                }, 
                                {
                                    "description": "Let's find out more about this invisible force which guides the compass. How strong is it? What shape is it?", 
                                    "id": "magnetic-fields", 
                                    "title": "Discovery of magnetic fields"
                                }, 
                                {
                                    "description": "How can we quantify the strength of magnetic fields? How strong is the Earth's field?", 
                                    "id": "measure-magnets", 
                                    "title": "Measuring magnetic fields"
                                }, 
                                {
                                    "description": "Basic observations leading to homemade batteries", 
                                    "id": "batteries", 
                                    "title": "Discovery of batteries"
                                }, 
                                {
                                    "description": "Discoveries leading to the Right Hand rule", 
                                    "id": "Electromagnet", 
                                    "title": "Discovery of electromagnetism"
                                }, 
                                {
                                    "description": "Exploring materials which cause a decrease in deflection when added in series with our meter.", 
                                    "id": "resistance", 
                                    "title": "Discovery of resistors"
                                }, 
                                {
                                    "description": "How can we turn electric current into rotational motion?", 
                                    "id": "electric_motor", 
                                    "title": "Electric motor"
                                }, 
                                {
                                    "description": "Discovering static electricity & electrostatic force. What is it? How can it be created, detected, and measured?", 
                                    "id": "electrostatics", 
                                    "title": "Electrostatics"
                                }
                            ], 
                            "description": "Rediscover the most important Scientific observations in a historical progression", 
                            "id": "discoveries", 
                            "title": "Discoveries"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Other household items you know", 
                                    "id": "reverse-engineering", 
                                    "title": "Household"
                                }, 
                                {
                                    "description": "Hair Dryer", 
                                    "id": "hair_dryer", 
                                    "title": "Hair dryer"
                                }, 
                                {
                                    "description": "DVD Player", 
                                    "id": "dvd_player", 
                                    "title": "DVD player"
                                }, 
                                {
                                    "description": "Digital Camera", 
                                    "id": "digital_camera", 
                                    "title": "Digital camera"
                                }
                            ], 
                            "description": "Videos exploring the way things work.", 
                            "id": "Reverse-Eng", 
                            "title": "Reverse engineering"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "This topic explains how Spout works! It was created by Karl R. C. Wendt.", 
                                    "id": "all-about-spout", 
                                    "title": "All about Spout"
                                }, 
                                {
                                    "description": "This project is based  on a MAKE Beetle bot. The tutorial was created by Karl R.C. Wendt.", 
                                    "id": "Spout-Bot-with-Solder", 
                                    "title": "Spout Bot with Solder"
                                }, 
                                {
                                    "description": "This project is based  on a MAKE Beetle bot. The tutorial was created by Karl R. C. Wendt.", 
                                    "id": "Solderless-Spout-Bot", 
                                    "title": "Spout Bot without Solder"
                                }, 
                                {
                                    "description": "Spider Bot is a low cost robot made of recycled components and designed by Karl R. C. Wendt", 
                                    "id": "Spider_bot", 
                                    "title": "Spider Bot"
                                }, 
                                {
                                    "description": "This project is a low cost robot made from every day items that are taken apart and described in the reverse engineering section. This project was created by Karl R. C. Wendt.", 
                                    "id": "Bit-zee", 
                                    "title": "Bit-zee Bot"
                                }
                            ], 
                            "description": "Start your own robotics project with Spout, Spider, and Bit-zee!", 
                            "id": "robots", 
                            "title": "Robots"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Introduction to the Lego NXT environment and what it is capable of. We begin with a few mini projects.", 
                                    "id": "lego-intro", 
                                    "title": "Introduction"
                                }, 
                                {
                                    "description": "Get to know your light sensor while building musical instruments", 
                                    "id": "lego-sensors", 
                                    "title": "Light guitar"
                                }, 
                                {
                                    "description": "Get to know your rotation sensor while building a 5 cent machine", 
                                    "id": "lego-coin-detector", 
                                    "title": "Coin detector"
                                }, 
                                {
                                    "description": "Build an ant colony with simple behaviours", 
                                    "id": "lego-antbot", 
                                    "title": "Ant bot"
                                }, 
                                {
                                    "description": "Collection of programming basics using NXT-G", 
                                    "id": "new-topic-2013-11-07T15:08:28.609Z", 
                                    "title": "Programming basics"
                                }
                            ], 
                            "description": "Introduction to the Lego NXT robotics platform", 
                            "id": "lego robotics", 
                            "title": "Lego robotics"
                        }, 
                        {
                            "description": "", 
                            "id": "Projectile_launcher", 
                            "title": "Projectile launcher"
                        }, 
                        {
                            "description": "", 
                            "id": "thermo-can", 
                            "title": "Thermo can"
                        }, 
                        {
                            "description": "", 
                            "id": "discovery-lab-2013", 
                            "title": "Discovery Lab 2013"
                        }, 
                        {
                            "description": "", 
                            "id": "Discovery-Lab-2012", 
                            "title": "Discovery Lab 2012"
                        }
                    ], 
                    "description": "", 
                    "id": "discoveries-projects", 
                    "title": "Discoveries and projects"
                }
            ], 
            "description": "", 
            "id": "science", 
            "title": "Science"
        }, 
        {
            "children": [
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "This tutorial (that only has one video) is an overview of what economics is.  In particular it will tell you the difference between microeconomics (the subject you're in right now) and macroeconomics.  Really good first watch to give you some context on the world of economics.", 
                                    "id": "economics-introduction", 
                                    "title": "Introduction to economics"
                                }, 
                                {
                                    "description": "You've probably heard of supply and demand.  Well, this tutorial focuses on the demand part.  All else equal, do people want more or less of something if the price goes down (what would you do)? Not only will you get an intuition for the way we typically depict a demand curve, you'll get an understanding for what might shift it.", 
                                    "id": "demand-curve-tutorial", 
                                    "title": "The demand curve"
                                }, 
                                {
                                    "description": "Now we'll focus on the \"supply\" part of supply and demand.  Supply curves (as we typically depict them) come out of the idea that producers will make more if they get paid more.", 
                                    "id": "supply-curve-tutorial", 
                                    "title": "The supply curve"
                                }, 
                                {
                                    "description": "You understand demand and supply.  This tutorial puts it all together by thinking about where the two curves intersect.  This point represents the equilibrium price and quantity which is, in an ideal world, where the market would transact.", 
                                    "id": "market-equilibrium-tutorial", 
                                    "title": "Market equilibrium"
                                }, 
                                {
                                    "description": "This tutorial tries to address a very important question in the real world--what drives oil prices?  And we will do it using the tools of the supply and demand curves.", 
                                    "id": "oil-prices-tutorial", 
                                    "title": "What drives oil prices"
                                }
                            ], 
                            "description": "The core ideas in microeconomics.  Supply, demand and equilibrium.", 
                            "id": "supply-demand-equilibrium", 
                            "title": "Supply, demand and market equilibrium"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "You're familiar with supply and demand curves already.  In this tutorial we'll explore what implications their steepness (or lack of) implies.  Price elasticity is a measure of how sensitive something is to price.", 
                                    "id": "price-elasticity-tutorial", 
                                    "title": "Price elasticity"
                                }
                            ], 
                            "description": "Price elasticity of demand and supply.  How sensitive are things to change in price.", 
                            "id": "elasticity-tutorial", 
                            "title": "Elasticity"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Many times, the equilibrium price is lower than the highest price some folks are willing to pay.  For all consumers, this is called consumer surplus.  Similarly, the price might be higher than the minimum price at which some are willing to produce.  For all the producers, this is called producer surplus.  This tutorial covers them both with an emphasis on the visual.", 
                                    "id": "consumer-producer-surplus-tut", 
                                    "title": "Consumer and producer surplus"
                                }, 
                                {
                                    "description": "We can often lose economic efficiency because of things like price floors, ceilings and taxes.  This loss in surplus (people who have more marginal benefit than marginal cost are not buying or people who have more marginal cost than benefit are buying) is called deadweight loss.", 
                                    "id": "deadweight-loss-tutorial", 
                                    "title": "Deadweight loss"
                                }, 
                                {
                                    "description": "In many scenarios thinking only about producers' marginal cost or consumers' marginal benefit does not fully capture *all* of the costs or benefits from the production/use of a product.  In this tutorial, we explore these externalities (negative and positive ones) to think a bit deeper about ways to maximize total surplus not just for producers and consumers, but for society as a whole.", 
                                    "id": "externalities-topic", 
                                    "title": "Public goods and externalities"
                                }
                            ], 
                            "description": "", 
                            "id": "consumer-producer-surplus", 
                            "title": "Consumer and producer surplus"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "This tutorial goes back to the basics.  You are a hunter-gatherer with only so much time to hunt or gather.  How do you allocate your time and energy to maximize you happiness?  This is what we try to understand through our study of the production possibilities frontier and opportunity cost.", 
                                    "id": "production-possibilities", 
                                    "title": "Production possibilities frontier"
                                }, 
                                {
                                    "description": "Should you try to produce everything yourself or only what you are best at and trade for everything else?  What if you're better than your trading partners at everything?  \n\nThis tutorial focuses on comparative advantage, specialization and gains from trade with a microeconomic lens.", 
                                    "id": "gains-from-trade-tutorial", 
                                    "title": "Comparative advantage and gains from trade"
                                }, 
                                {
                                    "description": "In this tutorial we look at the utility of getting one more of something and put numbers to it.  We then use this to construct a budget line and think about indifference curves.", 
                                    "id": "marginal-utility-tutorial", 
                                    "title": "Marginal utility and budget lines"
                                }
                            ], 
                            "description": "How do you decide what to produce or trade?  How can you maximize happiness in a world of scarcity.  What are you giving up when you choose something (i.e., opportunity cost)?", 
                            "id": "choices-opp-cost-tutorial", 
                            "title": "Scarcity, possibilities, preferences and opportunity cost"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Economic profit and accounting profit are two different things (the difference being that economic profit takes into account opportunity cost).  Confused?  This tutorial lays it all out with the example of a restaurant.", 
                                    "id": "economic-profit-tutorial", 
                                    "title": "Economic profit and opportunity cost"
                                }, 
                                {
                                    "description": "In this tutorial, Sal uses the example of an orange juice business to help us understand the ideas of average total cost (ATC), marginal cost (MC) and marginal revenue (MR).  We then use this understanding to answer the age-old question, \"how much orange juice should I produce?\"  Finally, we use these ideas to construct a long-run supply curve.  A must watch if you're interested in making juice!", 
                                    "id": "average-costs-margin-rev", 
                                    "title": "Average costs (ATC, MC) and marginal revenue (MR)"
                                }, 
                                {
                                    "description": "Using a spreadsheet, Sal walks through an example of average costs per line of code as a firm hires more engineers.  Really good primer to understand what average fixed costs, average variable costs, average total costs (ATC) and average marginal costs (MC) are (and how they are calculated).", 
                                    "id": "average-costs-tutorial", 
                                    "title": "Average fixed, variable and marginal costs"
                                }, 
                                {
                                    "description": "Constructing a demand curve for an individual firm by thinking about how much increment benefit they get from an incremental employee (marginal product of labor (MPL) and marginal product revenue (MPR).  We later think about how we can add these \"demand\" curves to construct a \"demand\" curve for the market for labor in this industry.", 
                                    "id": "labor-marginal-product-rev", 
                                    "title": "Labor and marginal product revenue"
                                }, 
                                {
                                    "description": "This short tutorial explores how a wine business can utilize first-degree price discrimination to maximize economic profit (it uses many of the ideas we've explored in the rest of this tutorial).", 
                                    "id": "price-discrimination-tutorial", 
                                    "title": "Price discrimination"
                                }
                            ], 
                            "description": "Economic profit vs. accounting profit.  Average total cost (ATC) and marginal cost (MC).  Marginal product of labor (MPL).  Price discrimination.", 
                            "id": "firm-economic-profit", 
                            "title": "Production decisions and economic profit"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "This tutorial looks at markets that are deemed to have \"perfect competition.\"  This means that there are many players with identical products, no barriers to entry, no advantage for existing players and good pricing information.  Few to no real market completely matches this theoretical ideal, but many are close.  Even the example we use in this tutorial (the airline industry) isn't quite perfect (you should think about why).", 
                                    "id": "perfect-competition", 
                                    "title": "Perfect competition"
                                }, 
                                {
                                    "description": "No, we aren't talking about the board game although the game does try to approximate what this tutorial is about--notice that you can charge more rent at either Boardwalk or Park Place if you own both (you have a \"monopoly\" in the navy blue market).\n\nThe opposite of perfect competition is when you have only one firm operating.  This tutorial explores what this firm would do to maximize economic profit.", 
                                    "id": "monopolies-tutorial", 
                                    "title": "Monopoly"
                                }, 
                                {
                                    "description": "Most markets sit somewhere in-between perfect competition and monopolies.  This tutorial explores some of those scenarios--from monopolistic competition to oligopolies and duopolies.", 
                                    "id": "monopolistic-competition-oligop", 
                                    "title": "Between perfect competition and monopoly"
                                }
                            ], 
                            "description": "", 
                            "id": "perfect-competition-topic", 
                            "title": "Forms of competition"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "If you haven't watched the movie \"A Beautiful Mind\", you should.  It is about John Nash (played by Russell Crowe) who won the Nobel Prize in economics for his foundational contributions to game theory.  This is what this tutorial is about.\n\nNash put some structure around how players in a \"game\" can optimize their outcomes (if the movie is to be fully believed, this insight struck him when he realized that if all his friends hit on the most pretty girl, he should hit on the second-most pretty one).  In this tutorial, we use the classic \"prisoner's dilemma\" to highlight this concept.", 
                                    "id": "nash-eq-tutorial", 
                                    "title": "Nash equilibrium"
                                }, 
                                {
                                    "description": "You know what Nash equilibrium is (from the other tutorial).  Now we apply it to a scenario that is fairly realistic--parties to a cartel cheating.\n\nA cartel is a group of actors that agree (sometimes illegally) to coordinate their production/pricing to maximize their collective economic profit.  What we will see, however, is that this is not a \"Pareto optimal\" state and they will soon start producing more than agreed on.", 
                                    "id": "cartels-cheat-tutorial", 
                                    "title": "Why parties in a cartel will cheat"
                                }
                            ], 
                            "description": "", 
                            "id": "nash-equilibrium-tutorial", 
                            "title": "Game theory and Nash equilibrium"
                        }
                    ], 
                    "description": "Topics covered in a traditional college level introductory microeconomics course", 
                    "id": "microeconomics", 
                    "title": "Microeconomics"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "Economics can some times get confusing because one person's expenditure is another person's income which can then be used for expenditure and on and on and on.  Seems very circular.  It is.\n\nThis tutorial helps us grapple with this and introduces us to the primary tool economists use to measure a nations productivity/income/expenditure--GDP (gross domestic product).", 
                                    "id": "circular-econ-gdp-tutorial", 
                                    "title": "GDP and the circular flow of income and expenditures"
                                }, 
                                {
                                    "description": "You already understand the circular nature of the economy and how GDP is defined from the last tutorial.  Now let's think about how economists define the composition of GDP.  In particular, we'll focus on consumption (C), investment (I), government spending (G) and net exports.", 
                                    "id": "GDP-components-tutorial", 
                                    "title": "Components of GDP"
                                }, 
                                {
                                    "description": "The value of a currency is constantly changing (usually going down in terms of what you can buy).  Given this, how can we compare GDP measured in dollars in one year to another year? This tutorial answers that question by introducing you to real GDP and GDP deflators.", 
                                    "id": "real-nominal-gdp-tutorial", 
                                    "title": "Real and nominal GDP"
                                }, 
                                {
                                    "description": "In this tutorial we will dig a bit into Thomas Piketty's popular \"Capital in the 21st Century\" that attempts to analyze the relationship(s) between economic growth, returns on capital and inequality. Our intent is to neither argue for nor against the ideas in the book, but rather use it as a tool for critical reasoning and discourse.", 
                                    "id": "piketty-capital", 
                                    "title": "National income and inequality"
                                }
                            ], 
                            "description": "Circular flow of income and expenditure.  Gross domestic product.", 
                            "id": "gdp-topic", 
                            "title": "GDP: Measuring national income"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "We might generally sense that our cost of living is going up (inflation), but how can we measure it?  This tutorial shows how it is done in the United States with the consumer price index (CPI).", 
                                    "id": "cost-of-living-tutorial", 
                                    "title": "Measuring cost of living --inflation and the consumer price index"
                                }, 
                                {
                                    "description": "We think we're getting a certain return on our investments, but can we put it in terms of real purchasing power since the value of money is constantly changing?  The answer is yes and this tutorial shows you how.", 
                                    "id": "real-nominal-return-tutorial", 
                                    "title": "Real and nominal return"
                                }, 
                                {
                                    "description": "Prices don't always go up.  Sometimes they go down (we call this deflation).  This tutorial explains how this happens.", 
                                    "id": "macroecon-deflation-tutorial", 
                                    "title": "Deflation"
                                }, 
                                {
                                    "description": "This tutorial walks through various scenarios of moderate and extreme price changes.  Very good way to understand how activity in the economy may impact price (and vice versa).", 
                                    "id": "deflation-inflation-scenarios-tutorial", 
                                    "title": "Inflationary and deflationary scenarios"
                                }, 
                                {
                                    "description": "Economists have notices a correlation between unemployment and correlation (you may wan to guess what type of correlation).  On some level, this tutorial is common sense, but it will give you fancy labels for this relation so that you can sound fancy at fancy parties.", 
                                    "id": "phillips-curve-tutorial", 
                                    "title": "The Phillips curve: Inflation and unemployment"
                                }
                            ], 
                            "description": "Inflation and deflation.  CPI-U. Real and nominal return.  Phillips Curve.", 
                            "id": "inflation-topic", 
                            "title": "Inflation - measuring the cost of living"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "This tutorial looks at supply and demand in aggregate-from the perspective of the entire economy (not just the market for one good or service).  Instead of thinking of quantity of one good, we think of total output (GDP).  Very useful model for thinking through macroeconomic events.", 
                                    "id": "aggregate-supply-demand-tut", 
                                    "title": "Aggregate demand and aggregate supply"
                                }, 
                                {
                                    "description": "In the last tutorial, we claimed that the aggregate demand and aggregate supply model (AD-AS) would be useful for analyzing macroeconomic events.  Well, in this tutorial, we'll do exactly that.", 
                                    "id": "historic-ad-as-scenarios", 
                                    "title": "Historical circumstances explained by AD/AS"
                                }, 
                                {
                                    "description": "Economies never have a long steady march upwards.  They constantly oscillate between growth and recession.  This tutorial gives a little intuition for why that is.", 
                                    "id": "business-cycle-tutorial", 
                                    "title": "The business cycle"
                                }, 
                                {
                                    "description": "Governments (and pseudo government entities like central banks) have two tools at their disposal to try to impact the business cycle --monetary and fiscal policy.  This will help you understand what they are.", 
                                    "id": "monetary-fiscal-policy", 
                                    "title": "Monetary and fiscal policy"
                                }, 
                                {
                                    "description": "Whether you love him or hate him (or just consider him a friend that you respect but disagree with every-now-and-then), Keynes has helped define how many modern governments think about their economies.  This tutorial explains how his thinking was a fundamental departure from classical economics.", 
                                    "id": "keynesian-thinking", 
                                    "title": "Keynesian thinking"
                                }
                            ], 
                            "description": "Aggregate demand and aggregate supply. Keynesian thinking. Demand-pull and cost-push inflation.  Fiscal and monetary policy.", 
                            "id": "aggregate-supply-demand-topic", 
                            "title": "Aggregate demand and aggregate supply"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Most modern economies use a counter-intuitive model of banking called \"fractional reserve banking.\"  It is counter-intuitive (and some people would say wrong) because it allows banks to lend out money that it tells depositors is available at any time and essentially involves private banks in money creation.  It also creates the possibility of mass instability through bank runs that tend to be mitigated through government regulation and insurance (some would say government subsidy of banks).\n\nThis tutorial explains how fractional reserve lending works and outlines the good and bad.  It also talks about the alternative of full reserve banking.", 
                                    "id": "fractional-reserve-banking-tut", 
                                    "title": "Fractional reserve banking"
                                }, 
                                {
                                    "description": "This short tutorial explains how we measure how much \"money\" there is out there.  As we'll see, this isn't as straightforward as counting dollars in people's pockets, especially because there are multiple type of money.", 
                                    "id": "money-supply-tutorial", 
                                    "title": "Money supply"
                                }, 
                                {
                                    "description": "If you already know a bit of what fractional reserve banking involves, this tutorial will take you deeper by looking at the actual accounting of central banks and banks.", 
                                    "id": "factional-reserve-accounting", 
                                    "title": "Fractional reserve accounting"
                                }, 
                                {
                                    "description": "", 
                                    "id": "interest-price-of-money-tutorial", 
                                    "title": "Interest as the price of money"
                                }
                            ], 
                            "description": "Fractional reserve banking and the money supply.", 
                            "id": "monetary-system-topic", 
                            "title": "The monetary system"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "If you earn a $1, you might spend some fraction of it.  This can then be income for someone else.  This can keep going.  \n\nIn this tutorial, we'll explore how the incremental spend per incremental earnings  (marginal propensity to consume) and the multiplier effect based on it can drive economic activity.", 
                                    "id": "MPC-tutorial", 
                                    "title": "Marginal propensity to consume (MPC)"
                                }, 
                                {
                                    "description": "We are steadily building up the tools to understand the Keynesian Cross and the IS-LM model.  In this tutorial, we begin to model consumption as a linear function of disposable income.  Seems reasonable to me.", 
                                    "id": "consumption-function", 
                                    "title": "Consumption function"
                                }, 
                                {
                                    "description": "We now build on our consumption function models and start to explore ideas of planned expenditures as a function of output.  When plotted with the actual output line, we get our Keynesian Cross which helps us think about whether the economy is operating at its potential.", 
                                    "id": "keynesian-cross-tutorial", 
                                    "title": "Keynesian cross"
                                }, 
                                {
                                    "description": "In this tutorial, we begin thinking about the impact of real interest rates on planned investment and output.  We then use this to help us plot the IS curve.  We then think about how, assuming a fixed money supply, as there is more economic activity, people are willing to pay more for money (helps us plot the LM curve).  Finally, we use the IS-LM model to think about how fiscal policy can impact both GDP and real interest rates.\n\nYou should watch the Keynesian Cross tutorial before this one.", 
                                    "id": "is-lm-model-tutorial", 
                                    "title": "IS-LM model"
                                }
                            ], 
                            "description": "Consumption function.  Marginal propensity to consume and multiplier.  Keynesian Cross and IS-LM model.", 
                            "id": "income-and-expenditure-topic", 
                            "title": "Income and expenditure: Keynesian cross and IS-LM model"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "In this tutorial we will see how trade and assets (including money) changing hands are fundamentally intertwined.  Not only that, but we will see how this can be accounted for through the capital account (assets changing hands) and current account (trade).", 
                                    "id": "current-capital-account", 
                                    "title": "Balance of payments- current account and capital account"
                                }, 
                                {
                                    "description": "This tutorial delves into how and why countries (usually their central banks) would want to keep other countries' currency in reserve.  It then goes into why this sometime leaves the reserve-holding country open to a speculative attack (this is seriously high drama).", 
                                    "id": "currency-reserves", 
                                    "title": "Currency reserves"
                                }
                            ], 
                            "description": "Balance of payments.  Current account.  Capital account.  Currency reserves and speculative attacks.", 
                            "id": "forex-trade-topic", 
                            "title": "Foreign exchange and trade"
                        }
                    ], 
                    "description": "Topics covered in a traditional college level introductory macroeconomics course", 
                    "id": "macroeconomics", 
                    "title": "Macroeconomics"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "Interest is the basis of modern capital markets.  Depending on whether you are lending or borrowing, it can be viewed as a return on an asset (lending) or the cost of capital (borrowing).\n\nThis tutorial gives an introduction to this fundamental concept, including what it means to compound.  It also gives a rule of thumb that might make it easy to do some rough interest calculations in your head.", 
                                    "id": "compound-interest-tutorial", 
                                    "title": "Compound interest basics"
                                }, 
                                {
                                    "description": "Most of us have borrowed to buy something.  Credit cards, in particular, can be quite convenient (but dangerous if not used in moderation).\n\nThis tutorial explains credit card interest, how credit card companies make money and a far more silly way of borrowing money called \"payday\" loans.", 
                                    "id": "credit-card-interest", 
                                    "title": "Credit cards and loans"
                                }, 
                                {
                                    "description": "This is an older tutorial (notice the low-res, bad handwriting) about one of the coolest numbers in reality and how it falls out of our innate desire to compound interest continuously.", 
                                    "id": "cont-comp-int-and-e", 
                                    "title": "Continuous compound interest and e"
                                }, 
                                {
                                    "description": "If you gladly pay for a hamburger on Tuesday for a hamburger today, is it equivalent to paying for it today?\n\nA reasonable argument can be made that most everything in finance really boils down to \"present value\".  So pay attention to this tutorial.", 
                                    "id": "present-value", 
                                    "title": "Present value"
                                }, 
                                {
                                    "description": "Back in the day (like medieval Europe), you would actually be thrown in jail if you couldn't pay your debts (debtor's prison).  That seemed like a pretty awful thing to do (not to mention that lenders are much less likely to be paid by someone rotting in prison), so governments created an \"out\" called bankruptcy (which, as you'll see, is a pseudo-painful \"reset\" button on your finances).", 
                                    "id": "personal-bankruptcy-tut", 
                                    "title": "Personal bankruptcy"
                                }
                            ], 
                            "description": "", 
                            "id": "interest-tutorial", 
                            "title": "Interest and debt"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "This old and badly drawn tutorial covers a topic essential to anyone planning to not live in the woods -- your personal balance sheet.  Since homes are usually the biggest part of these personal balance sheets, we cover that too.", 
                                    "id": "home-equity-tutorial", 
                                    "title": "Home equity and personal balance sheets"
                                }, 
                                {
                                    "description": "Most people buying a home need a mortgage to do so.  This tutorial explains what a mortgage is and then actually does some math to figure out what your payments are (the last video is quite mathy so consider it optional).", 
                                    "id": "mortgages-tutorial", 
                                    "title": "Mortgages"
                                }, 
                                {
                                    "description": "Is it always better to buy than rent?  What if home prices go up dramatically and rents don't?  How can we compare home prices to rents to figure out what to do.\n\nThis older tutorial (low-res, bad handwriting) walks us through this.  It is about housing but similar thinking can be applied to any rent-vs-buy decision (spoiler alert, Sal did eventually buy a home).", 
                                    "id": "renting-v-buying", 
                                    "title": "Renting vs. buying a home"
                                }, 
                                {
                                    "description": "Back before the 2008 credit crisis, Sal was perplexed by why housing prices were going up so fast and theorized that it was a bubble forming (he was right).  \n\nThese pre-2008 videos are fun from a historical point-of-view since they were made before all the poo poo hit the fan.", 
                                    "id": "housing-price-conundrum", 
                                    "title": "Housing price conundrum"
                                }, 
                                {
                                    "description": "This tutorial talks about how the housing-bubble-induced credit crisis unfolded with a focus on the derivative securities that helped pump the bubble.", 
                                    "id": "credit-crisis", 
                                    "title": "Credit crisis"
                                }, 
                                {
                                    "description": "In the fall of 2008, it became clear that a cascade of bank failures was happening because of shoddy loans and exotic securities (both which fueled a now popping housing bubble).  In an attempt to avoid a depression, the Treasury Secretary (Hank Paulson) wanted to pour $1 Trillion into the same banks that had created the mess.\n\nThis tutorial walks us through the beginnings of the mess and possible solutions.  Historical note: it was created as the crisis was unfolding.", 
                                    "id": "paulson-bailout", 
                                    "title": "Paulson bailout"
                                }, 
                                {
                                    "description": "When are you using capital to create more things (investment) vs. for consumption (we all need to consume a bit to be happy).  When you do invest, how do you compare risk to return?  Can capital include human abilities?\n\nThis tutorial hodge-podge covers it all.", 
                                    "id": "investment-consumption", 
                                    "title": "Investment and consumption"
                                }
                            ], 
                            "description": "", 
                            "id": "housing", 
                            "title": "Housing"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "$1 went a lot further in 1900 than today (you could probably buy a good meal for the family for $1 back then).  Why?  And how do we measure how much more expensive things have gotten (i.e., inflation)?", 
                                    "id": "inflation-basics-tutorial", 
                                    "title": "Inflation basics"
                                }, 
                                {
                                    "description": "This tutorial starts with a very \"micro\" view of when firms decide to raise (or lower prices).  It then jumps back to the macro view to discuss how capacity utilization can impact prices.", 
                                    "id": "cap-util-inflation", 
                                    "title": "Capacity utilization and inflation"
                                }
                            ], 
                            "description": "", 
                            "id": "inflation-tutorial", 
                            "title": "Inflation"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Benjamin Franklin (and several other writers/philosophers) tells us that \"In this world nothing can be said to be certain, except death and taxes.\"  He's right.  \n\nThis tutorial focus on personal income tax.  Very important to watch if you ever plan on earning money (some of which the government will take for itself).", 
                                    "id": "taxes", 
                                    "title": "Personal taxes"
                                }, 
                                {
                                    "description": "In exchange for being treated as a person-like-legal entity (and the limited liability this gives for its owners), most corporations pay taxes.  This tutorial focuses on what corporations are, \"double taxation\" and a few ways that multinationals might try to get out of paying taxes.", 
                                    "id": "corporate-taxation", 
                                    "title": "Corporate taxation"
                                }
                            ], 
                            "description": "", 
                            "id": "taxes-topic", 
                            "title": "Taxes"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Just keeping track of cash that goes in and out of a business doesn't always reflect what's going on.  This tutorial compares cash and accrual accounting.  Very valuable if you ever plan on starting or investing in any type of business (you might also discover a nascent passion for accounting)!", 
                                    "id": "cash-accrual-accounting", 
                                    "title": "Cash versus accrual accounting"
                                }, 
                                {
                                    "description": "Corporations use three financial statements to report what's going on: balance sheets, cash flow statements and income statements.  They can be derived from each other and each give a valuable lens on the operations and condition of a business.  \n\nAfter you know the basics of accrual accounting (available in another tutorial), this tutorial will give you tools you need to responsibly understand any business.", 
                                    "id": "financial-statements-tutorial", 
                                    "title": "Three core financial statements"
                                }, 
                                {
                                    "description": "How do you account for things that get \"used up\" or a cost that should be spread over time.  This tutorial has your answer.  Depreciation and amortization might sound fancy, but you'll hopefully find them to be quite understandable.", 
                                    "id": "depreciation-amortization-tut", 
                                    "title": "Depreciation and amortization"
                                }
                            ], 
                            "description": "", 
                            "id": "accounting-and-financial-stateme", 
                            "title": "Accounting and financial statements"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Many people own stocks, but, unfortunately, most of them don't really understand what they own.  This tutorial will keep you from being one of those people (not keep you from owning stock, but keep you from being ignorant about your investments).", 
                                    "id": "stocks-intro-tutorial", 
                                    "title": "Introduction to stocks"
                                }, 
                                {
                                    "description": "Can you sell something that you borrowed from someone else?  Why, yes, you can and it is called \"shorting\".  Why would you do this?  Well, you can now make money if the price goes down.  Is this bad?  This tutorial has your answers.", 
                                    "id": "shorting-stock", 
                                    "title": "Shorting stock"
                                }, 
                                {
                                    "description": "If you understand what a stock is (also a good idea to look at the topic on accounting and financial statements), then you're ready to dig in a bit on a company's actual financials.\n\nThis tutorial does this to help you understand what the price of a company really is.", 
                                    "id": "company-statements-capital-struc", 
                                    "title": "Understanding company statements and capital structure"
                                }, 
                                {
                                    "description": "Life is full of people who will try to convince you that something is a good or bad idea by spouting technical jargon.  Most of them have no idea what they are talking about.  Don't be one of those people or their victims when it comes to stocks.\n\nFrom P/E rations to EV/EBITDA, we've got your back!", 
                                    "id": "valuation-and-investing", 
                                    "title": "Corporate metrics and valuation"
                                }, 
                                {
                                    "description": "This is an old set of videos, but if you put up with Sal's messy handwriting (it has since improved) and spotty sound, there is a lot to be learned here.  In particular, this tutorial walks through starting, financing and taking public a company (and even talks about what happens if it has trouble paying its debts).", 
                                    "id": "venture-capital-and-capital-markets", 
                                    "title": "Life of a company--from birth to death"
                                }, 
                                {
                                    "description": "When companies issue new shares, many people consider this a share \"dilution\"--implying that the value of each share has been \"watered down\" a bit.  This tutorial walks through the mechanics and why--assuming management isn't doing something stupid--the shares might not be diluted at all.", 
                                    "id": "dilution-tutorial", 
                                    "title": "Dilution"
                                }, 
                                {
                                    "description": "Companies often buy or merge with other companies using shares (which is sometimes less intuitive than when they use cash).  This tutorial walks through the mechanics of how this happens and details what is likely to happen in the public markets because of the transaction (including opportunities for arbitrage).", 
                                    "id": "mergers-acquisitions", 
                                    "title": "Mergers and acquisitions"
                                }, 
                                {
                                    "description": "Private equity firms often borrow money (use leverage) to buy companies.  This tutorial explains how they do it and pay the debt.", 
                                    "id": "leveraged-buy-outs", 
                                    "title": "Leveraged buy-outs"
                                }, 
                                {
                                    "description": "Both corporations and governments can borrow money by selling bonds.  This tutorial explains how this works and how bond prices relate to interest rates.  In general, understanding this not only helps you with your own investing, but gives you a lens on the entire global economy.", 
                                    "id": "bonds-tutorial", 
                                    "title": "Bonds"
                                }
                            ], 
                            "description": "", 
                            "id": "stock-and-bonds", 
                            "title": "Stocks and bonds"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "If we're not in the mood to research and pick our own stocks, mutual funds and/or ETFs might be a good option.  This tutorial explains what they are and how they are different.", 
                                    "id": "mutual-funds", 
                                    "title": "Mutual funds and ETFs"
                                }, 
                                {
                                    "description": "The government apparently wants us to save for retirement (not always obvious because it also wants us to spend as much as possible to pump the economy going into the next election cycle).  To encourage this, it has created some ways to save that avoid or defer taxes: IRAs and 401ks.", 
                                    "id": "ira-401ks", 
                                    "title": "Retirement accounts: IRAs and 401ks"
                                }, 
                                {
                                    "description": "It is a bit of a downer to think about, but we are all going to die.  Do we care what happens to our loved ones (if they really are \"loved\" than the answer is obvious).  This tutorial walks us through the options to insure our families against losing us.  The reason why we stuck it in the \"investment vehicles\" topic is because it can also be an investment that we can use before we die.", 
                                    "id": "life-insurance", 
                                    "title": "Life insurance"
                                }, 
                                {
                                    "description": "Hedge funds have absolutely nothing to do with shrubbery.  Their name comes from the fact that early hedge funds (and some current ones) tried to \"hedge\" their exposure to the market (so they could, in theory, do well in an \"up\" or \"down\" market as long as they were good at picking the good companies).  Today, hedge funds represent a huge class investment funds.  \n\nThey are far less regulated than, say, mutual funds.  In exchange for this, they aren't allowed to market or take investments from \"unsophisticated\" investors.  Some use their flexibility to mitigate risk, other use it to amplify it.", 
                                    "id": "hedge-funds", 
                                    "title": "Hedge funds"
                                }
                            ], 
                            "description": "", 
                            "id": "investment-vehicles-tutorial", 
                            "title": "Investment vehicles, insurance and retirement"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "We all use money and most of us use banks.  Despite this, the actual working of the banking system is a bit of a mystery to most (especially fractional reserve banking).\n\nThis older tutorial (bad handwriting and resolution) starts from a basic society looking to do more than barter and incrementally builds to a modern society with fraction reserve banking. Through this process, you will hopefully gain a deep understanding of how money and banking works in our modern world.", 
                                    "id": "banking-and-money", 
                                    "title": "Banking and money"
                                }, 
                                {
                                    "description": "You know that the Federal Reserve (or central banks in general) controls the money supply and short-term interest rates.  But how exactly do they do this.  Even more, how is \"quantitative easing\" different than regular open market operations.\n\nThis tutorial explains it all in the context of the Federal Reserves attempts to stave off deflation during the 2008-2012 recession.", 
                                    "id": "federal-reserve", 
                                    "title": "Quantitative easing"
                                }, 
                                {
                                    "description": "The poop really started to hit the fan in the fall of 2008.  When the new administration took office in early 2009, the poop was still there.  This is tutorial explains an attempt--probably not a well thought out one--to clean the poop and slow the fan.\n\nVideos on the Geithner Plan to solve the continuing banking crisis in early 2009.", 
                                    "id": "geithner-plan", 
                                    "title": "Geithner plan"
                                }, 
                                {
                                    "description": "This tutorial walks through how China's undervaluing of its currency impacts trade and prices (which also fuels cheap borrowing for the U.S.).", 
                                    "id": "currency-tutorial", 
                                    "title": "Foreign exchange and trade"
                                }, 
                                {
                                    "description": "This tutorial contains short videos that explain how China and the United States are intertwined through currency and debt.  This is key for understanding the current global macro picture.", 
                                    "id": "china-us-debt-situation", 
                                    "title": "Chinese currency and U.S. debt"
                                }, 
                                {
                                    "description": "The Greek government incurred debt beyond its means but didn't have control over its own currency to inflate away its obligations.  From austerity, to a bailout, to leaving the Eurozone, none of the options looked great.\n\nIn this tutorial, Sal walks through the situation Greece was in and its options (these videos were made as the crisis was unfolding).", 
                                    "id": "greek-debt-crisis", 
                                    "title": "2011-2012 Greek debt crisis"
                                }, 
                                {
                                    "description": "Learn about bitcoins and how they work.  \n\nVideos by Zulfikar Ramzan. Zulfikar is a world-leading expert in computer security and cryptography and is currently the Chief Scientist at Sourcefire.  He received his Ph.D. in computer science from MIT.", 
                                    "id": "bitcoin", 
                                    "title": "Bitcoin"
                                }
                            ], 
                            "description": "", 
                            "id": "money-and-banking", 
                            "title": "Money, banking and central banks"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Options allow investors and speculators to hedge downside (or upside).  It allows them to trade on a belief that prices will change a lot--just not clear about direction.  It allows them to benefit in any market (with leverage) if they speculate correctly.\n\nThis tutorial walks through option basics and even goes into some fairly sophisticated option mechanics.", 
                                    "id": "put-call-options", 
                                    "title": "Put and call options"
                                }, 
                                {
                                    "description": "In many commodities markets, it is very helpful for buyers or sellers to lock-in future prices.  This is what both forwards and futures allow for.  This tutorial explains how they work and what the difference is between the two.", 
                                    "id": "forward-futures-contracts", 
                                    "title": "Forward and futures contracts"
                                }, 
                                {
                                    "description": "What started out as a creative way to spread risk ended up fueling a monster housing bubble.  This tutorial explains what mortgage-backed securities are and how they work.", 
                                    "id": "mort-backed-secs-tut", 
                                    "title": "Mortgage-backed securities"
                                }, 
                                {
                                    "description": "", 
                                    "id": "CDO-tutorial", 
                                    "title": "Collateralized debt obligations"
                                }, 
                                {
                                    "description": "", 
                                    "id": "credit-default-swaps-tut", 
                                    "title": "Credit default swaps"
                                }, 
                                {
                                    "description": "", 
                                    "id": "interest-rate-swaps-tut", 
                                    "title": "Interest rate swaps"
                                }, 
                                {
                                    "description": "Options have been bought and sold for ages, but finding a rational way to price them seemed beyond our mathematical know-how... until 1973 when Fischer Black and Myron Scholes showed up and gave us the Black-Scholes model.  This work was later extended by Robert Merton and now underpins much of modern finance.", 
                                    "id": "Black-Scholes", 
                                    "title": "Black-Scholes formula"
                                }
                            ], 
                            "description": "", 
                            "id": "derivative-securities", 
                            "title": "Options, swaps, futures, MBSs, CDOs, and other derivatives"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Unemployment is a key metric for judging the health of an economy (and even political stability).  This tutorial is a primer on what it is and how it's measured (which you might find surprising).", 
                                    "id": "unemployment-tutorial", 
                                    "title": "Unemployment"
                                }
                            ], 
                            "description": "Discussions of economic topics and how they relate to current events.", 
                            "id": "current-economics", 
                            "title": "Current economics"
                        }
                    ], 
                    "description": "Videos on finance and macroeconomics", 
                    "id": "core-finance", 
                    "title": "Finance and capital markets"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "Richard Branson, Chairman of the Virgin Group, shares his story as a successful entrepreneur with a diverse portfolio.", 
                                    "id": "richard-branson", 
                                    "title": "Richard Branson - Chairman of the Virgin Group"
                                }, 
                                {
                                    "description": "", 
                                    "id": "elon-musk", 
                                    "title": "Elon Musk - CEO of Tesla Motors and SpaceX"
                                }, 
                                {
                                    "description": "Marc Ecko, Founder of Ecko Unlimited, discusses his origins as an entrepreneur and the entrepreneurial culture of Hip Hop. Describing graffiti as the extreme sport of art, Marc talks about how this form of artistic expression was his gateway to entrepreneurship and offers advice to young people.", 
                                    "id": "marc-ecko", 
                                    "title": "Marc Ecko - Founder of Ecko Unlimited"
                                }, 
                                {
                                    "description": "", 
                                    "id": "thomas-friedman", 
                                    "title": "Thomas Friedman - Author"
                                }, 
                                {
                                    "description": "Philip Rosedale, Founder of Coffee and Power, discusses his recent venture and how a student\u2019s education today can lead to a career tomorrow.", 
                                    "id": "philip-rosedale", 
                                    "title": "Philip Rosedale - Founder and Chairman of Second Life"
                                }, 
                                {
                                    "description": "Zach Kaplan, CEO of Inventables, discusses how the revolution of digital manufacturing and desktop publishing can impact a new generation of entrepreneurs.", 
                                    "id": "zach-kaplan", 
                                    "title": "Zach Kaplan - CEO of Inventables"
                                }, 
                                {
                                    "description": "", 
                                    "id": "davis-guggenheim", 
                                    "title": "Davis Guggenheim - Filmmaker"
                                }, 
                                {
                                    "description": "T.A. McCann, Founder and CEO of Gist, talks about his entrepreneurial journey, including how he joined the America\u2019s Cup sailing team. T.A. discusses how entrepreneurs need to show initiative and chart their own course, advising other founders to always ask questions and make progress.", 
                                    "id": "ta-mccann", 
                                    "title": "T.A. McCann - Founder and CEO of Gist"
                                }, 
                                {
                                    "description": "Ben Milne, CEO of Dwolla, discusses his motivation in founding his company and the excitement of starting something new. Ben advocates for the idea that failure, which can happen in big and small ways, does not have to be your legacy.", 
                                    "id": "ben-milne", 
                                    "title": "Ben Milne - CEO of Dwolla"
                                }, 
                                {
                                    "description": "Giles Shih, President and CEO of BioResource International, describes his company and explains how producing \"big green chickens\" will help feed the world.", 
                                    "id": "giles-shih", 
                                    "title": "Giles Shih - President and CEO of BioResource International"
                                }, 
                                {
                                    "description": "Danny O\u2019Neill, President of The Roasterie, describes the journey that led him to starting his own company as well as some of the key attributes of an entrepreneur.", 
                                    "id": "danny-oneill", 
                                    "title": "Danny O'Neill - President of The Roasterie"
                                }, 
                                {
                                    "description": "Lara Morgan, Founder of Pacific Direct, shares her entrepreneurial story and describes her motivations in founding companies. Lara describes how understanding the mechanisms of money, along with a fearlessness of asking questionshelped her company grow.", 
                                    "id": "lara-morgan", 
                                    "title": "Lara Morgan - Founder of Pacific Direct"
                                }, 
                                {
                                    "description": "", 
                                    "id": "scott-cook", 
                                    "title": "Scott Cook - Founder and Chairman of the Executive Committee, Intuit"
                                }, 
                                {
                                    "description": "", 
                                    "id": "angela-ahrendts-tutorial", 
                                    "title": "Angela Ahrendts - CEO of Burberry"
                                }, 
                                {
                                    "description": "When Dave Smith came to the harsh realization and he alone was in charge of his future, he took a resourceful route to become an expert in his field. Mixing the desire to make it with the imagination to fake it, he went to great lengths to connect with TekScape IT customers and make them believe that his tiny organization was big enough to solve their trickiest problems.", 
                                    "id": "dave-smith", 
                                    "title": "Dave Smith - CEO & Founder of TekScape IT"
                                }, 
                                {
                                    "description": "Renaud Laplanche was opening his mail when the idea for Lending Club came to him. He tells the story of seeing \n\nthe opportunity and creating the online Lending Club to fill the gap in the financial industries market. Laplache\u2019s\n\ncompetitive nature extends to one-man sailboat racing and he compares the risks and rewards of racing with setting\n\nthe pace as an entrepreneur.", 
                                    "id": "renaud-laplance", 
                                    "title": "Renaud Laplanche - Founder of Lending Club"
                                }, 
                                {
                                    "description": "Jason Christiansen has heard all the familiar comparisons between running a business and being a team player, but as a former major league baseball player, he steps to the plate with a unique perspective. Christiansen talks about building Rigid Industries and how the company deals with imitation product lines and compares the pressure of standing on the mound to standing before his team of employees.", 
                                    "id": "jason-christiansen", 
                                    "title": "Jason Christiansen - President & CEO of Rigid Industries"
                                }, 
                                {
                                    "description": "A passion for science education led Linda Jeschognig from her life in accounting to a second act as an entrepreneur. She talks about the inspiration behind Hands-on Labs and overcoming the obstacles with a company created to send kits containing hydrochloric acid, cobalt nitrate and other hazardous elements to college chemistry students. Along the way, Jeschofnig has gained support and reached out to guide other women on the entrepreneurial path.", 
                                    "id": "Linda-Jeschofnig", 
                                    "title": "Linda Jeschofnig - Co-founder of Hands-On Labs"
                                }, 
                                {
                                    "description": "LaKeskia Grant founded Virtual Enterprise Architects as a place where she would have a voice and create an environment where others could be heard. She discusses her industry and encourages would-be entrepreneurs to incorporate their core values in their business. Grant\u2019s mother may not know exactly what the information technology business does, but she instilled a strong work ethic and the spirit of entrepreneurship in her daughter.", 
                                    "id": "lakeshia-grant", 
                                    "title": "LaKeshia Grant - CEO & Founder of Virtual Enterprise Architects"
                                }
                            ], 
                            "description": "Personal lessons and insights from accomplished entrepreneurs are the basis of this interview series produced by the Ewing Marion Kauffman Foundation and Khan Academy.", 
                            "id": "interviews-entrepreneurs", 
                            "title": "Interviews with entrepreneurs"
                        }
                    ], 
                    "description": "", 
                    "id": "entrepreneurship2", 
                    "title": "Entrepreneurship"
                }
            ], 
            "description": "Microeconomics, macroeconomics, finance, accounting and capital markets.", 
            "id": "economics-finance-domain", 
            "title": "Economics and finance"
        }, 
        {
            "children": [
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "Called the Great War (before World War II came about), World War I was the bloody wake-up call that humanity was entering into a new stage of civilization.  Really the defining conflict that took Europe from 19th Century Imperial states that saw heroism in war into a modern shape.  Unforunately, it had to go through World War II as well (that some would argue was due to imbalances created by World War I).", 
                                    "id": "world-war-I-tutorial", 
                                    "title": "Beginning of World War I"
                                }, 
                                {
                                    "description": "Naval blockades in World War I to starve enemy nation of trade.\n\nContrary to what many think, American entry into WWI was not due purely to the sinking of the Lusitania.  Learn more about what caused the United States to play its first major direct role in a European conflict.", 
                                    "id": "american-entry-world-war-I", 
                                    "title": "Blockades and American entry"
                                }, 
                                {
                                    "description": "This tutorial goes into some detail to describe the tactics and battles of the two major fronts of World War I--the Western Front and the Eastern Front.", 
                                    "id": "world-war-I-fighting", 
                                    "title": "Western and Eastern fronts of World War I"
                                }, 
                                {
                                    "description": "Contrary to what some history books and movies would have you believe, World War I was not just fought on the Western and/or Eastern fronts.  Because of the empires involved, it was a truly global conflict.  This tutorial will cover some of the campaigns that your history book might not (but are important to understanding the War).", 
                                    "id": "other-fronts-ww1", 
                                    "title": "Other fronts of World War I"
                                }, 
                                {
                                    "description": "The Middle East is a center of cultures, religions, and, unfortunately, conflict in our modern world.  This tutorial takes us from a declining Ottoman Empire to the modern Middle East which is still the center of many religions, cultures and conflicts.", 
                                    "id": "middle-east-20th-century", 
                                    "title": "World War I shapes the Middle East"
                                }, 
                                {
                                    "description": "World war I (or the Great War) was a defining event for the 20th Century.  It marked the end (or beginning of the end) of centuries-old empires and the dawn-of newly independent states based on ethnic and linguistic commonality.   It didn't just change the face of Europe, it changed the face of the world.\n\nFrom the Paris Peace Conference and Treaty of Versailles, we'll see how the end of World War I may have been just the set up for even more conflict in Europe and the world.", 
                                    "id": "ww1-aftermath", 
                                    "title": "Aftermath of World War I"
                                }, 
                                {
                                    "description": "Test your comprehension of the causes, dynamics and aftermath of World War I (as covered in the tutorials in this topic) by taking this quiz.", 
                                    "id": "world-war-i-quiz", 
                                    "title": "World War I Quiz"
                                }, 
                                {
                                    "description": "How did the National Socialists (Nazis) go from being a tiny, marginal party in the early 1920s to having full control of Germany and catalyzing World War II?  Who was Hitler and what was his philosophy and how did he come to power?", 
                                    "id": "hitler-nazis", 
                                    "title": "Rise of Hitler and the Nazis"
                                }, 
                                {
                                    "description": "The word \"Fascist\" is now a pejorative term (\"pejorative\" means \"negative\" or \"derogatory\") to describe leaders or states that have absolute control and are aggressively nationalistic.\n\nThe terms \"fascism\" and \"fascist\", however, were first embraced by Benito Mussolini in Italy in the 1920s and 1930s to describe their party and policies (that were absolutist and aggressively nationalistic).  \n\nThis tutorial described Mussolini and the Fascists' rapid rise to power and the influence it had on the rest of the world (including providing a model for Hitler in Germany).", 
                                    "id": "mussolini-fascism", 
                                    "title": "Rise of Mussolini and Fascism"
                                }, 
                                {
                                    "description": "The early 1900s marked the end of thousands of years of dynastic imperial rule in China.  It also marked the beginning of a complex period of fragmentation, civil war and fending off Japanese imperial ambitions.  This tutorial covers everything from the establishment of the Republic of China by Sun Yat-sen to the Warlord Era to the Chinese Civil War between the Chiang Kai-Shek led Kuomintang and the Communists led by Mao Zedong.", 
                                    "id": "China-early-1900s", 
                                    "title": "Overview of Chinese history 1911-1949"
                                }, 
                                {
                                    "description": "The cold war between the United States and the Soviet and their respective allies never involved direct conflict (which might have ended the world).  Instead, it involved posturing, brinksmanship and proxy wars in far-flung regions of the world.", 
                                    "id": "cold-war", 
                                    "title": "The Cold War"
                                }
                            ], 
                            "description": "You cannot properly understand current world events without understanding the history of the 20th Century. This topic takes us on a journey from the end of Imperialism through two world wars and the Cold War and brings us to our modern world.", 
                            "id": "euro-hist", 
                            "title": "1900 - present: The recent past"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "In this tutorial Walter Isaacson walks Sal through the United States Declaration of Independence.  In doing so, they discuss the philosophical underpinnings of the American Revolution and the United States in general.\n\nWalter Isaacson is the President and CEO of the Aspen Institute.  He is the former CEO and Chairman of CNN and Managing Editor of Time Magazine.  He has written best-selling biographies of Steve Jobs, Benjamin Franklin, Albert Einstein and Henry Kissinger.\n", 
                                    "id": "declaration-of-independence", 
                                    "title": "US Declaration of Independence"
                                }, 
                                {
                                    "description": "\"Let them eat cake!\"  \"No, how about we cut your head off instead!\"  \n\nThe French Revolution was ugly, bloody and idealistic.  This tutorial covers the beginning of the end of the Bourbon rule (actually doesn't really go away for 60 years) and birth of France as a Republic (which will really take about 80 years).", 
                                    "id": "french-revolution-tutorial", 
                                    "title": "French Revolution"
                                }, 
                                {
                                    "description": "A man with such a huge \"Napoleonic complex\", that they named it after him.  A military genius with a ginormous ego, some people consider him a hero or a tyrant or both.\n\nFrance has successfully overthrown Louis XVI in 1789.  It has gone through a many-year period of bloodshed and instability.  The monarch's of Europe are not happy about this \"overthrow-your-king\" business.  A 5'6'' Corsican establishes himself as a strong military tactician during the wars with other European powers and soon comes to power in France.\n\nThis tutorial covers the rise and fall of one of the most famous men in all of history: Napoleon Bonaparte (Napoleon I).", 
                                    "id": "napoleon-bonaparte", 
                                    "title": "Napoleon Bonaparte"
                                }, 
                                {
                                    "description": "Unlike the American Revolution which fairly cleanly transitioned the United States from British rule to a republic, France's process of democratization was much longer and more painful.  This tutorial gives a scaffold of that (and gives some context for the book/musical/movie \"Les Miserables\").", 
                                    "id": "many-french-revolutions", 
                                    "title": "France's many revolutions and republics"
                                }, 
                                {
                                    "description": "Yes, you are right. Haiti is not in Europe.  We put the tutorial here because it was a French colony and its own revolution is closely linked to that of France's.\n\nPossibly one of the saddest histories that a nation can have, this tutorial tries to give as much context as possible for the birth of Haiti.", 
                                    "id": "haitian-revolution", 
                                    "title": "Haitian Revolution"
                                }, 
                                {
                                    "description": "In many ways, Benjamin Franklin is the \"Founding Father\" of the United States of America that best represent many ideals of the country.  In this series with Walter Isaacson, we go into the life and philosophy of Franklin.", 
                                    "id": "benjamin-franklin", 
                                    "title": "Life of Benjamin Franklin"
                                }
                            ], 
                            "description": "Do we need kings?  Can people govern themselves?  What rights do we all have?  Can science and understanding uplift all of humanity?\n\nThis topic lays the foundation for our modern thinking about the world.  From democratic revolutions to the establishment of empires backed by industrial power.", 
                            "id": "1600s-1800s", 
                            "title": "1700-1900: Enlightenment and Revolution"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "In 1517 a German theologian and monk, Martin Luther, challenged the authority of the Pope and sparked the Protestant Reformation. His ideas spread quickly, thanks in part to the printing press. By challenging the power of the Church, and asserting the authority of individual conscience (it was increasingly possible for people to read the bible in the language that they spoke), the Reformation laid the foundation for the value that modern culture places on the individual.", 
                                    "id": "protestant-reformation", 
                                    "title": "The Protestant Reformation"
                                }
                            ], 
                            "description": "A tutorial about the Protestant Reformation", 
                            "id": "1500-1600-Renaissance-Reformation", 
                            "title": "1500-1600: Renaissance and Reformation"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "This tutorial includes the Ancient Near East, and Ancient Greece and Rome.", 
                                    "id": "Ancient", 
                                    "title": "Ancient"
                                }, 
                                {
                                    "description": "", 
                                    "id": "medieval", 
                                    "title": "Medieval"
                                }
                            ], 
                            "description": "", 
                            "id": "ancient-medieval", 
                            "title": "Before 1300: Ancient and Medieval history"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "us-history", 
                                    "title": "United States history overview"
                                }
                            ], 
                            "description": "The tutorials in this topic will take you on sweeping journeys through time so that you can get the really BIG picture for how things fit together.", 
                            "id": "history-survey", 
                            "title": "Surveys of history"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "what-happens-when-you-stay-put-2", 
                                    "title": "What happens when you stay put (the Neolithic revolution & early River Valley civilizations)"
                                }, 
                                {
                                    "description": "", 
                                    "id": "so-thats-where-that-comes-from-2", 
                                    "title": "Oh, so that\u2019s where that comes from! (the ancient Greeks, Persians, Indians, Chinese & the trade between them. Oh, and also the Romans)"
                                }, 
                                {
                                    "description": "", 
                                    "id": "whats-God-got-to-do-with-It-2", 
                                    "title": "What\u2019s God got to do with it? - a lot (Early Christianity, Byzantium, Islam, and Medieval Europe)"
                                }, 
                                {
                                    "description": "", 
                                    "id": "road-trip-conquest-trade-2", 
                                    "title": "Road trip! (conquest, trade, & more conquest)"
                                }, 
                                {
                                    "description": "", 
                                    "id": "when-people-do-great-and-really-terrible-things-2", 
                                    "title": "When people do great and really terrible things (The Renaissance, Colonialism, & the Slave Trade)"
                                }, 
                                {
                                    "description": "", 
                                    "id": "you-aint-the-boss-of-me-2", 
                                    "title": "You ain\u2019t the boss of me! Oh, maybe you are (Revolution and Modern Society)"
                                }, 
                                {
                                    "description": "", 
                                    "id": "nationalism-imperialism-globalization-2", 
                                    "title": "Nationalism, Imperialism & Globalization: the good, the bad and the really, really ugly"
                                }
                            ], 
                            "description": "John Green teaches you the history of the world in 42 episodes of Crash Course. Learn, study and understand all the important civilizations, empires, wars, and revolutions the world has seen so far.", 
                            "id": "CrashCourse-WorldHistory", 
                            "title": "Crash Course: World History"
                        }, 
                        {
                            "description": "", 
                            "id": "Ellis-quiz", 
                            "title": "Ellis Video Quiz"
                        }
                    ], 
                    "description": "The history of the world (eventually)!", 
                    "id": "history", 
                    "title": "History"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "art-history-introduction", 
                                    "title": "Introduction"
                                }, 
                                {
                                    "description": "If you\u2019ve ever found yourself saying \u201cHow can that be art?,\u201d then this tutorial is for you! We\u2019ve tried to answer the real questions that come up during a typical visit to a modern art museum. Learn how describing can help you slow down and better understand what a work of art is communicating. Learn how important historical context is and how meaning can change over time. This tutorial asks: Why is art important? How can a snow shovel be art? How can we find meaning in abstract art?", 
                                    "id": "the-basics", 
                                    "title": "The basics"
                                }, 
                                {
                                    "description": "Watching a soccer game is a lot more interesting if you\u2019ve actually played the game yourself. Similarly, art makes a lot more sense if you understand how it was made. Different materials can have a profound effect on how a work of art looks and how we respond to it. Learn about how artist\u2019s made their own supplies before there were art supply stores! Understand the differences between oil and tempera and how marble is quarried and carved.", 
                                    "id": "media", 
                                    "title": "Media and Technique"
                                }, 
                                {
                                    "description": "See conservators in action and learn about the work a conservator does in different media.", 
                                    "id": "conserving-works-of-art", 
                                    "title": "The conservation of works of art"
                                }
                            ], 
                            "description": "New to art? If so, this is a good place to start. We often think we should understand what we see and that we know what we like, but art can be challenging. It has meant different things at different moments in history. Art gives us access to the way other people have seen the world. Jump in and explore!", 
                            "id": "introduction-to-art-history", 
                            "title": "Art History Basics"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "You\u2019ve seen the drawing of human evolution showing a procession of monkey, ape, primitive and modern man? Well, somewhere along that line early man could be shown holding a paint brush and a chisel. Mankind has been making art for at least 100,000 years. Why was the earliest art made? What might it have once meant? This tutorial focuses on what we do and do not know about one of the earliest representations of the human body, The Venus of Willendorf.", 
                                    "id": "prehistoric", 
                                    "title": "Prehistoric"
                                }, 
                                {
                                    "description": "Was writing invented to record poetry or great literature? Nope. Writing was invented to help keep track of beer and other goods and services! The ancient Sumerians were nothing if not practical. Ancient cultures established the first cities and large scale architecture. From the Gates of the City of Ancient Babylon, to the ancient code of laws instituted by King Hammurabi, the Ancient Near East is strangely distant but also remarkably familiar.", 
                                    "id": "ancient-near-east", 
                                    "title": "Ancient Near East"
                                }, 
                                {
                                    "description": "Woody Allen famously said, \u201cI don't want to achieve immortality through my work. I want to achieve it through not dying.\u201d The ancient Egyptians on the other hand, confronted death head-on. In fact, the art of the ancient Egyptians was (for the most part) never meant to be seen by the eyes of the living\u2014it was meant to benefit the dead in the afterlife. Throughout human history, art has been recognized for its ability to outlive us and has been used as a receptacle for our fears and hopes about our own mortality.", 
                                    "id": "ancient-egypt", 
                                    "title": "Ancient Egypt"
                                }, 
                                {
                                    "description": "Excavations led by teams of archaeologists in the nineteenth century hoped to find evidence for places and people in Homer's epic poems The Iliad and The Odyssey. They may not have discovered what they sought, but along the way, they made remarkable discoveries. The tutorial covers the art of the Cycladic Islands, and the Island of Crete (Minoan), and of Mainland Greece (Mycenaean).", 
                                    "id": "aegean-art", 
                                    "title": "Ancient Aegean"
                                }, 
                                {
                                    "description": "The ancient Greeks kept busy. They produced painting and sculpture that was copied by the ancient Romans, by Renaissance and Baroque masters, and by the royal academies up until the 19th century. We still copy ancient Greek architecture, refer to their philosophy, use their geometry, perform their theatre, hold olympic games, and redefine their democracy.", 
                                    "id": "ancient-greece", 
                                    "title": "Ancient Greece"
                                }, 
                                {
                                    "description": "Before the small village of Rome became \u201cRome\u201d with a capital R (to paraphrase D.H. Lawrence), a brilliant civilization once controlled almost the entire peninsula we now call Italy. This was the Etruscan civilization, a vanished culture whose achievements set the stage not only for the development of ancient Roman art and culture but for the Italian Renaissance as well.", 
                                    "id": "Etruscan-art", 
                                    "title": "Etruscan art"
                                }, 
                                {
                                    "description": "The Romans weren\u2019t very original (they borrowed the Greek\u2019s and Egyptian\u2019s gods, architecture, etc.), but they sure knew the political value of art and they were brilliant engineers and administrators. This tutorial traces Roman art and architecture from the Republic through the collapse of the Empire and the rise Christianity. Fly over a reconstruction of the ancient city of Rome. Understand how the Colosseum was built to appease a population angry at the excesses of the former Emperor Nero, and uncover the secret initiation rites buried by the ash of Mount Vesuvius.", 
                                    "id": "ancient-rome", 
                                    "title": "Ancient Rome"
                                }, 
                                {
                                    "description": "Buddhism began when Siddh\u0101rtha renounced his princely life and succeeded in attaining enlightenment.  As the philosophy and practice of Buddhism traveled, it was shaped and reshaped first across Northern India, Pakistan and Afghanistan and later in China, Japan and South East Asia. Learn how we trace the history of Buddhism through the representation of the historical Buddha and the many other buddhas that are still widely venerated today.", 
                                    "id": "buddhist-art", 
                                    "title": "Buddhist Art"
                                }
                            ], 
                            "description": "Humans have been making art for tens of thousands of years, long before there was writing. Why was Egyptian art obsessed with death? Why did the ancient Greeks seek the perfect human form? How did the ancient Romans use art as state propaganda? Why was the naturalism of ancient Greek and Roman art abandoned with the rise of Christianity? This topic explores the art of the ancient world, from the Venus of Willendorf to a 6th-Century Chinese Bodhisattva.", 
                            "id": "art-history-400-c-e--ancient-cultures-1", 
                            "title": "- 400 C.E. Ancient cultures"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "An overview of Europe in the middle ages.", 
                                    "id": "a-beginners-guide-to-the-medieval-period", 
                                    "title": "A beginner's guide to the medieval period"
                                }, 
                                {
                                    "description": "The first Christians were often persecuted in the Ancient Roman empire, but when\u2014thanks to Constantine\u2014Christianity became legal in the 4th century, Christians could worship openly and the first churches were built in Rome and Christians could be buried in tombs sculpted with Christian imagery. This tutorial takes you on a tour of early Christian churches, and takes a close look at the sarcophagus of a Roman senator who died in 359.", 
                                    "id": "early-christian", 
                                    "title": "Early Christian"
                                }, 
                                {
                                    "description": "Christian art, which was initially influenced by the illusionary quality of classical art, started to move away from naturalistic representation and instead pushed toward abstraction. Artists began to abandon classical artistic conventions like shading, modeling and perspective\u2014conventions that make the image appear more real. They no longer observed details in nature to record them in paint, bronze, marble, or mosaic.", 
                                    "id": "anglo-saxon-england", 
                                    "title": "Early Medieval"
                                }, 
                                {
                                    "description": "Today, we know the city of Constantinople as Istanbul (in fact there\u2019s a song about that!). But even before it was Constantinople, it was the ancient city of Byzantium, and it was renamed Constantinople (city of Constantine) by none other than the Emperor Constantine himself (it\u2019s good to be the emperor!). From there a succession of emperors ruled the Byzantine empire as the Roman empire dissolved. For two centuries, the Byzantine empire even included the Italian city of Ravenna, where  many churches decorated with astoundingly beautiful mosaics can still be found. In Byzantine art we see a departure from the naturalism of the ancient Greek and Roman world. Figures float in ethereal gold heavenly spaces in mosaics, and we find intricate carvings made from ivory, a luxurious material imported from Africa.", 
                                    "id": "byzantine", 
                                    "title": "Byzantine"
                                }, 
                                {
                                    "description": "More than 1 billion people call themselves muslim and this monotheistic religion is now estimated to be the second largest in the world. Islamic culture was among the most advanced and tolerant during the Medieval era. Cities from Isfahan in the East to Grenada in the West became important centers of art and learning. This tutorial looks at the sculpture, tilework, costume and interior spaces of this brilliant culture.", 
                                    "id": "islamic-art", 
                                    "title": "Arts of the Islamic world"
                                }, 
                                {
                                    "description": "Charlemagne, King of the Franks and later Holy Roman Emperor, instigated a cultural revival known as the Carolingian Renaissance.", 
                                    "id": "carolingian", 
                                    "title": "Carolingian"
                                }, 
                                {
                                    "description": "Otto I (who became emperor in 962) lends his name to the \u201cOttonian\u201d period. He forged an important alliance with the Pope, which allowed him to be crowned the first official Holy Roman Emperor since 924.", 
                                    "id": "ottonian", 
                                    "title": "Ottonian"
                                }, 
                                {
                                    "description": "Visogoths, Ostrogoths, and Vikings, oh my! Western Europe was not a peaceful place during the 600 years after the fall of the Roman Empire. Western Europe (what is now Italy, France, Spain, England, etc.) had been repeatedly invaded. The result was a fractured feudal society with little stability and little economic growth. Charlemagne and the Ottonians had partially and briefly unified the West, and of course the Church was a stabilizing institution, but it was only in the 11th Century that everything changed. Now there was finally enough peace and prosperity to allow for travel and for the widespread construction of large buildings. These were, with rare exceptions, the first large structures to be built in the West since the fall of the Romans so many centuries before. We call the period Romanesque (Roman-like) because the masons of this period looked back to the architecture of ancient Rome. The relative calm of the Romanesque period also meant it was possible to travel, and the faithful set out on pilgrimages in great numbers to visit holy relics in churches across Europe. This meant that ideas and styles also traveled, towns grew and churches were built and enlarged.", 
                                    "id": "romanesque", 
                                    "title": "Romanesque"
                                }, 
                                {
                                    "description": "No, we\u2019re not talking about the dark subculture we know as Goth! We\u2019re talking about the style of art and architecture In Europe from the 1100s to the beginnings of the Renaissance at about 1400. Hopefully by the end of this tutorial when someone says Gothic, you\u2019ll think of enormous stained-glass windows in churches whose vaulted ceilings reach toward heaven and not black clothing and dark eyeliner!", 
                                    "id": "gothic", 
                                    "title": "Gothic"
                                }, 
                                {
                                    "description": "If you are an art historian with expertise in this area and would like to contribute content, please contact Beth or Steven.", 
                                    "id": "art-of-the-americas", 
                                    "title": "Art of the Americas"
                                }, 
                                {
                                    "description": "These questions focus on works of art from across the different periods of the middle ages.", 
                                    "id": "Overview-Quiz-Medieval-Art", 
                                    "title": "Overview quiz on medieval art"
                                }
                            ], 
                            "description": "Were the Middle Ages really all that dark? Hardly! How could we call the period that saw the building of Chartres Cathedral with its stunning stained-glass windows, dark? Sure, the Roman empire collapsed, but with the Christianization of Europe came magnificent churches, illuminated bibles, and intricately designed broaches. This period also saw the birth of Islam, the third great monotheistic religion.", 
                            "id": "art-history-400-1300-medieval---byzantine-eras", 
                            "title": "400-1300 Medieval Era"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "When we think of the Renaissance, we tend to think of Florence (and Rome). But the city of Siena also deserves our attention. Today, the lovely walled city of Siena is one of the best preserved Medieval cities in Europe and it was chosen by the United Nations as a World Heritage Site. In the 14th Century, Siena was an independent nation and often at war with its neighbor, Florence. Some of  the most important art of the 14th Century was commissioned for Siena\u2019s Cathedral and town hall. Duccio and his students, the Lorenzetti Brothers and Simone Martini produced large-scale painting with an intricacy and subtle coloration that is unique in the Renaissance.", 
                                    "id": "siena", 
                                    "title": "Siena"
                                }, 
                                {
                                    "description": "When Vasari wrote his enormously influential book, Lives of the Artists, in the 16th century, he credited Giotto, the 14th century Florentine artist with beginning \"the great art of painting as we know it today, introducing the technique of drawing accurately from life, which had been neglected for more than two hundred years.\" In other words, for Vasari, Giotto was the first artist to leave behind the medieval practice of painting what one knows and believes, for the practice of painting what one sees. This tutorial looks at painting and sculpture in both Pisa and Florence to highlight some of the most forward-thinking art of this century.", 
                                    "id": "florence", 
                                    "title": "Florence"
                                }, 
                                {
                                    "description": "Art from the Yuan dynasty", 
                                    "id": "ChinaYuanDynasty", 
                                    "title": "China"
                                }
                            ], 
                            "description": "This is a transitional period. In the art of Florence and Siena there is a move away from medieval abstract depictions of space and the human body as artists began to focus on the illusion of mass and space and the expression of human emotion. With hindsight, it is possible to trace elements of Renaissance art back to this period. This century saw the creation of the beautiful poetry of Dante and Petrarch, but it is also the century that saw the worst outbreak of the Bubonic plague (known then as the Black Death) which wiped out close to half the population of Europe\u2014a terrifying statistic, difficult to imagine today. This topic focuses on two Italian city-states\u2014Florence and Siena, both proud republics in the 14th century, and the great painters of those city-states, Giotto and Cimabue in Florence, and Duccio, Martini and the Lorenzetti brothers in Siena.", 
                            "id": "art-history-1300-1400-proto-renaissance", 
                            "title": "1300-1400 Proto-Renaissance"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "beginners-guide-to-Renaissance", 
                                    "title": "A beginner's guide to the Renaissance"
                                }, 
                                {
                                    "description": "No, not the color and not the wine! In the 15th century, the duchy of Burgundy was one of the most powerful regions in Europe, and stretched from what is today central France up to what is today Belgium and Holland. The home of the Dukes of Burgundy was Dijon, and Duke Philip the Bold commissioned some of the century's greatest works there, including a Carthusian monastery just outside the city walls, where he hoped to be buried so the monks could pray for his soul for eternity. He hired some of the most brilliant artists in Europe to work for him there, including Claus Sluter. Very little of the monastery survives today, but thankfully Sluter\u2019s great work, The Well of Moses, can still be seen there.", 
                                    "id": "burgundy", 
                                    "title": "Burgundy"
                                }, 
                                {
                                    "description": "In the 15th century, Flanders (which is the northern portion of Belgium today) was ruled by the Dukes of Burgundy. The enormous wealth of the court of the Dukes and the wealth of the merchant class (in the thriving cities of Bruges and Tournai) made for a new interest in art that mimicked the material world, though in a way that was quite different from what was happening concurrently in Florence. Oil paint comes into its own in the work of Jan van Eyck and Rogier van der Weyden, and we see how the artists of the North used it to create stunning illusions of fur, wood, wool, glass, and jewels.", 
                                    "id": "flanders", 
                                    "title": "Flanders"
                                }, 
                                {
                                    "description": "Walking through the streets of Florence in the summer isn\u2019t always easy, it\u2019s jam packed with students and tourists who have come to study and admire the city\u2019s treasures including Michelangelo\u2019s David, Botticelli\u2019s Birth of Venus, and the engineering brilliance of Brunelleschi. Florence in the 15th Century was fabulously wealthy thanks to its banking and manufacturing families. The Medici, the de-facto rulers of the city, were bankers who commissioned some of the most important art of the Renaissance. Florence was also a center of the Humanist revival that in many ways is what separates our Modern world from the Medieval era.", 
                                    "id": "florence-1", 
                                    "title": "Florence"
                                }, 
                                {
                                    "description": "Renaissance Venice was a city of merchants that traded with the Byzantine and Islamic Empires to the East, with the Germanic nations North of the Alps, and with Kingdoms to the West. In the 15th Century, Venice was at the height of its power with colonies and a well equipped navy to protect its merchant fleet abroad. Its fabulous wealth financed the construction of sumptuous churches and palaces\u2014and art to fill them. The city\u2019s salty, humid air meant that frescos faded quickly and so in the late 15th century, artists adopted oil, a medium they had seen used on panels from the north. By the late 15th century, they had also adopted canvas as their support of choice and artists like Giovanni Bellini created some of the most subtle and engaging art ever made.", 
                                    "id": "venice", 
                                    "title": "Venice"
                                }, 
                                {
                                    "description": "Currently this tutorial contains the work of only one artist, Michael Pacher. It would have been so much easier if we could have included him in Venice, since Pacher was influenced by the work of the great Venetian painter Mantegna. But Pacher spoke German, and the specific area he was from (today in the north-east of Italy), was known as Tyrol (though there is a state of Tyrol today in Austria). Confusing, we know. In this tutorial, we take a look at Pacher\u2019s amazing St. Wolfgang Altarpiece which is still in the church it was made for\u2014a church on a lake surrounded by mountains in Austria, still visited by religious pilgrims. Most altarpieces in the Renaissance were made of many interconnected panels that were later sold and ended up in different collections, and this means that to see one altarpiece you usually have to travel to many museums. But this is not true of the St. Wolfgang altarpiece. Seeing a Renaissance work of art in the space it was made for helps us to travel back in time to the late 15th Century.", 
                                    "id": "tyrol", 
                                    "title": "Tyrol"
                                }, 
                                {
                                    "description": "The International Gothic Style persists into the 15th Century in many courts in Europe including England.", 
                                    "id": "england", 
                                    "title": "England"
                                }, 
                                {
                                    "description": "Art in France excluding Burgundy", 
                                    "id": "France-1400-1500", 
                                    "title": "France"
                                }, 
                                {
                                    "description": "This quiz features is a painting that does not appear in any tutorial in this section, though it does date to this century (1400-1500). It is an \u201cunknown\u201d for you to test your skill and knowledge about Renaissance art. Some of the questions may require knowledge beyond the videos in this set of tutorials.", 
                                    "id": "1400s-quiz", 
                                    "title": "1400s quiz"
                                }
                            ], 
                            "description": "This is the century that sees the full realization of the Renaissance and the end of the medieval way of thinking about the world. The Humanist rediscovery of ancient Greek and Roman culture is supported by the wealth accumulated in prosperous cities such as Bruges, Florence, and Venice. New wealth and increasing trade created a demand for an art based on the world we see. The second half of the century saw the invention of the printing press, and Columbus\u2019s voyage. And though he was heading for the East, Columbus landed in the Americas, and suddenly there were vast new continents for Europe to exploit economically and to Christianize. The century begins with the magnificent sculptures of Claus Sluter and ends with the elegant figures of Leonardo da Vinci.", 
                            "id": "art-history-1400-1500-renaissance-in-italy-and-the-north", 
                            "title": "1400-1500 Renaissance in Italy and the North"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "We don\u2019t call this the \u201cHigh\u201d Renaissance for nothing! This period sees hugely ambitious projects, from Michelangelo\u2019s painting of the Sistine Chapel ceiling and the rebuilding of St. Peter\u2019s in Rome, to Raphael\u2019s frescoes in the papal palace. We use this term to refer to the art of the Italian Renaissance, beginning with Leonardo, whose great masterpiece the Last Supper, actually dates to the last decades of the 15th century (history is never neat!). In the painting and sculpture of this period, ideally beautiful figures who move gracefully, often in complex, multi-figure compositions conveying the sense that human beings are an echo of the perfection of God.", 
                                    "id": "high-renaissance", 
                                    "title": "High Renaissance: Florence and Rome"
                                }, 
                                {
                                    "description": "The light is different in Venice, the sun glints off the city\u2019s watery streets illuminating Renaissance palaces and churches filled with the art of Bellini, Giorgione, Tintoretto, Veronese and Titian. Perhaps due to the complex play of light reflected off the canals and Byzantine mosaics, Venetian art is known for its brilliant color and subtle tone. The great Venetian artists produced many of the most important paintings of the Renaissance, but their work was different from their colleagues in Florence and Rome who found inspiration in ancient ruins. The Venetians favored the sumptuous, the exotic and the poetic and created art for a society that had grown wealthy trading with distant lands.", 
                                    "id": "venice-1", 
                                    "title": "Venice"
                                }, 
                                {
                                    "description": "You could say that High Renaissance painters had achieved it all\u2014ideally beautiful, graceful figures, rational spaces, and unified compositions with dozens of figures. If you were a young artist in the early decades of the 1500s you might have felt that there was nothing left to accomplish! Renaissance art was always based on the visual world\u2014on representing things as we see them, but Mannerist art was more artificial, it looked to other art rather than to nature, and Mannerist artists purposely looked for complexity and difficulty to showcase their skills. Figures are elongated, the illusion of space that was so important for the Renaissance no longer makes sense, and the human body is often impossibly twisted.", 
                                    "id": "mannerism", 
                                    "title": "Mannerism"
                                }, 
                                {
                                    "description": "The Renaissance in the North continues, but now with the impact of the Protestant Reformation, where there was growing concern that images in the church violated the commandment against making likenesses, as part of the prohibition against worshipping idols. The Reformation had a direct impact on some of the greatest painters of this period, including the German artists Durer, who converted, and Cranach, who was a close friend of Luther. There was increasing exchange during this period between artists in Italy and those in Northern Europe in terms of both methods and style, though the two styles remain distinct. Here we see some of the most complex painting in the work of Holbein, some of the most playful in the work of Bruegel and some of the most terrifying in the work of Bosch.", 
                                    "id": "northern-renaissance", 
                                    "title": "Northern Renaissance"
                                }, 
                                {
                                    "description": "In 1517 a German theologian and monk, Martin Luther, challenged the authority of the Pope and sparked the Protestant Reformation. His ideas spread quickly, thanks in part to the printing press. By challenging the power of the Church, and asserting the authority of individual conscience (it was increasingly possible for people to read the bible in the language that they spoke), the Reformation laid the foundation for the value that modern culture places on the individual.", 
                                    "id": "the-protestant-reformation", 
                                    "title": "The Protestant Reformation"
                                }, 
                                {
                                    "description": "", 
                                    "id": "japan", 
                                    "title": "Japan"
                                }
                            ], 
                            "description": "If there was one century in the past that saw radical changes in established ways of thinking comparable to the 20th Century, it would be the 16th. Before this, in Western Europe, there was only one type of Christianity\u2014under the authority of the Pope in Rome. But in 1517 a German theologian and monk, Martin Luther, sparked the Protestant Reformation. His ideas spread quickly, thanks in part to the printing press. Luther challenged the power of the Pope and the Church, and asserted the authority of individual conscience. At the same time, it was increasingly possible for people to read the bible in the languages that they spoke. It is also during this period that the Scientific Revolution began and observation replaced religious doctrine as the source of our understanding of the universe and our place in it. At mid-century, Copernicus suggested that the sun was at the center of solar system (not the earth), radically repositioning human beings and therefore calling into question our centrality in the universe that God had created.", 
                            "id": "art-history-1500-1600-end-of-the-renaissance-and-the-reformation", 
                            "title": "1500-1600 End of the Renaissance and the Reformation"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "beginners-guide-baroque", 
                                    "title": "A beginner's guide to the Baroque"
                                }, 
                                {
                                    "description": "Baroque painting, sculpture and architecture in Italy seems to miraculously unite the heavenly and the earthly to deepen the faith of believers. We\u2019ll look at the utterly convincing illusions of heaven on the painted ceilings of Il Gesu and St. Ignazio, and the way Caravaggio painted biblical scenes with a gritty realism that makes them look as though they are taking place on the streets of Rome. And of course we explore the great genius of the period, Bernini, who used every means at his disposal\u2014painting, sculpture and architecture\u2014in works like The Ecstasy of St. Theresa and the Cathedra Petri to bring the viewer closer to the divine.", 
                                    "id": "italy", 
                                    "title": "Italy"
                                }, 
                                {
                                    "description": "This tutorial focuses on the art of Peter Paul Rubens, whose work was in high demand by nearly every King, Queen and aristocrat in Catholic Europe (good thing he had a huge workshop!). Rubens was a master of color, dramatic compositions, and movement. Although he was from Northern Europe, he traveled to Italy and absorbed the art of the Renaissance, of classical antiquity, and of Caravaggio. He painted nearly every type of subject\u2014landscapes, portraits, mythology, and history paintings.", 
                                    "id": "flanders-1", 
                                    "title": "Flanders"
                                }, 
                                {
                                    "description": "In the Protestant Dutch Republic of the 17th century there was an enormous demand for art from a wide cross-section of the public. This was a very good thing, since the institution that had been the main patron for art\u2014the Church\u2014was no longer in the business of commissioning art due to the Protestant Reformation. Dutch artists sought out new subjects of interest to their new clientele, scenes of everyday life (genre paintings), landscapes and still-lifes. There was also an enormous market for portraits. One of the greatest artist of this period, Rembrandt, made his name as a portrait painter, but was also a printmaker, and his work also includes moving interpretations of biblical subjects (though from a Protestant perspective).", 
                                    "id": "holland", 
                                    "title": "Holland"
                                }, 
                                {
                                    "description": "The main focus of this tutorial, and a leading artist at this time is the great Diego Velazquez, who spent most of his career as the court painter to the King of Spain painting official portraits. But in the hands of Velazquez, even mundane portraits became masterpieces of brushwork and color. His early work was influenced by the realism of Caravaggio. Get up close to the princess in his later masterpiece, Las Meninas (The Maids of Honor), and you\u2019ll see broad brushstrokes of red, pink, black and white, but step back and they magically resolve to create a perfect illusion of the silk of her dress and the light moving across her face and hair. No other artist, except perhaps Titian and Rubens, revealed so honestly the alchemy of painting\u2014how paint can be turned into reality.", 
                                    "id": "spain", 
                                    "title": "Spain"
                                }, 
                                {
                                    "description": "In France, the LeNain Brothers painted scenes of every-day life (genre paintings), often depicting peasants. There was a renewal of interest in their art in the mid-Nineteenth Century, when the art critic, Champfluery wrote that the brothers \u201cconsidered men in tatters more interesting than courtiers in embroidered garments.\u201d At the same time, Poussin created a very different style\u2014one that was highly intellectual and looked back to Renaissance, and ancient Greek and Roman art.", 
                                    "id": "france", 
                                    "title": "France"
                                }
                            ], 
                            "description": "The 17th Century is the era of the Baroque style, characterized by energy, drama, and movement. The Church in Rome needed art that spoke to its resurgent power even as the conflict between Protestant and Catholics continued. A new realism\u2014with a special sensitivity to light\u2014also pervades the art of this period across Europe and can be seen especially in the work of Caravaggio, Velazquez, Ruysdael, and Vermeer. But where in Catholic countries, the Church remained a major patron of religious images, in the Protestant Dutch Republic, artists painted an expanded range subjects like still-lifes, landscapes and genre paintings for the middle class.", 
                            "id": "art-history-1600-1700-the-baroque", 
                            "title": "1600-1700 The Baroque"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "It\u2019s hard not to like Rococo art. After all, it\u2019s subjects are often about luxury and pleasure, which makes sense since its patrons were the extremely wealthy French aristocracy. This tutorial features two romantic liaisons\u2014Fragonard\u2019s The Swing and The Meeting, portraits and a mythological subject, \u201cVenus Consoling Love.\u201d You get the idea.", 
                                    "id": "rococo", 
                                    "title": "Rococo"
                                }, 
                                {
                                    "description": "Jacques Louis David, an active supporter of the Revolution of 1789, is the star of this tutorial. David served in the revolutionary government, used his art in the service of its cause\u2014and voted to behead King Louis XVI. He captured the patriotism of the revolution\u2019s early phase and later, memorialized its dead heroes. And when the revolution failed, and Napoleon came to power, David used his great talents to present a heroic image of that military general-turned emperor. David invents a new style for the democratic values of the Enlightenment\u2014one that is the very opposite of the luxuriousness of the Rococo\u2014and that looks back to Renaissance and ancient Greek art, hence the name\u2014Neo-Classicism (new classicism).", 
                                    "id": "neo-classicism", 
                                    "title": "Neo-Classicism"
                                }, 
                                {
                                    "description": "Britain and America in the Age of Revolutions (Reynolds, Copley, Peale)\n\tIt was hard to be an artist in America during the colonial period, and for decades after too. There were no real art schools, no grand tradition of art, and no wealthy aristocratic patrons to commission heroic subjects. Americans were practical, and they wanted portraits\u2014and not paintings of classical mythology (which didn\u2019t always make American artists, at least those with wider ambitions, happy). As you\u2019ll learn in this tutorial, Copley was the greatest American portrait painter of the period, and Peale, who studied with Copley, painted portraits of American heroes such as George Washington, Thomas Jefferson and Benjamin Franklin, and founded what became the first real American art museum. American artists looked to England for support and inspiration, often to the older Sir Joshua Reynolds, who was the painter to the King, and first President of the Royal Academy in London.", 
                                    "id": "english-portraiture", 
                                    "title": "Britain & America in the Age of Revolution"
                                }, 
                                {
                                    "description": "Art and culture from the European invasion of the Americas to the end of the colonial era.", 
                                    "id": "Colonial-Americas", 
                                    "title": "Colonial Americas"
                                }
                            ], 
                            "description": "From the frivolous paintings of Fragonard to the politically-charged moralizing images of David, this tutorial brings us from the King of France and his court\u2014the 1%\u2014to the democratic aspirations of the French and American revolutionaries. The Kings of France ruled by divine right, but Enlightenment thinkers (for example, Voltaire and Diderot) asserted our ability to reason for ourselves rather than rely on the teachings of established institutions. Rousseau in \u201cThe Social Contract,\u201d stated that power to govern resided in the hands of the people. In 1788 the new United States ratified its Constitution, and in 1793, King Louis XVI was beheaded. Artists in France, America and Britain\u2014some sympathetic to revolutionary ideals, others not\u2014were nevertheless all caught up in the political upheavals of this period.", 
                            "id": "art-history-1700-1800-age-of-enlightenment", 
                            "title": "1700-1800 Age of Enlightenment"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Romanticism begins in France with the violent and exotic battle scenes of Gros and the famous shipwreck, the Raft of the Medusa, painted by Gericault. Soon after, two distinct trends emerge in French painting, one\u2014represented by the artist Delacroix\u2014was rebellious, and emphasized emotion, color and loose brushwork. The other\u2014which can be seen in the art of Ingres\u2014upheld tradition, and emphasized line and a highly finished surface.  Of course, things were more complicated\u2014but those were battle lines!", 
                                    "id": "romanticism-in-france", 
                                    "title": "Romanticism in France"
                                }, 
                                {
                                    "description": "The great artist Francisco Goya is the focus of this tutorial. Goya began his career designing tapestries for the royal residences, and eventually became court painter to the King of Spain. But after Napoleon\u2019s army occupied Spain and deposed the King, Goya documented the horrors he witnessed. His work following the occupation, including the Third of May 1808, remains some of the most powerful anti-war images ever created. His later years were spent largely in a house outside Madrid which he painted with haunting scenes. Saturn Devouring his sons belongs to this late series, known as the \u201cBlack Paintings.\u201d", 
                                    "id": "romanticism-in-spain", 
                                    "title": "Romanticism in Spain"
                                }, 
                                {
                                    "description": "As the industrial revolution transformed the British countryside, replacing fields with factories, painters turned to landscape. Constable painted his native suffolk, where he spent his childhood, and imbued it with a sense of affection for rural life. Turner, on the other hand, created dramatic and sublime landscapes with a sense of the heroic or even the tragic. What both of these artists have in common is a desire to make landscape painting\u2014understood as a low subject by the Academy which dictated official views on art\u2014carry serious meaning.", 
                                    "id": "romanticism-in-england", 
                                    "title": "Romanticism in England"
                                }, 
                                {
                                    "description": "This tutorial focuses exclusively on the art of Caspar David Friedrich, whose work best exemplifies Romanticism\u2019s interest in the big questions of man\u2019s mortality and place in the universe. The world had changed dramatically since the time of Michelangelo, Bernini and Rembrandt, and as a result, Friedrich approached these big questions without the Christian narratives that dominated the art of the past. And like his English counterparts during this period, he imbues nature and the landscape with symbolic and often spiritual meaning.", 
                                    "id": "romanticism-in-germany", 
                                    "title": "Romanticism in Germany"
                                }, 
                                {
                                    "description": "", 
                                    "id": "romanticism-in-the-united-states", 
                                    "title": "Romanticism in the United States"
                                }
                            ], 
                            "description": "With the failure of the French Revolution (Napoleon crowned himself Emperor, and after his defeat, a King was restored to power in France), there was a turn away from public, political life, toward personal, subjective experience. In large part, this turn characterizes the new style of Romanticism (don\u2019t confuse this with our own use of the term romantic!), whether we look to art in France, Spain, England or Germany. Where Neo-Classical painters created virtuous and heroic subjects with figures willing to sacrifice for the public good, Romantic painters asserted the primacy of emotion and the irrational.", 
                            "id": "art-history-1800-1848-industrial-revolution-i", 
                            "title": "1800-1848 Industrial Revolution I"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "In 1848, a small group of young artists banded together and formed \u201cThe Pre-Raphaelite Brotherhood,\u201d a name which sounds intentionally backward-looking and medieval. The Pre-Raphaelites looked back to art before the time of Raphael (before about 1500 that is)\u2014before the art of the Renaissance was reduced to formulas followed for centuries by artists associated with the art academies of Europe. Their idea was that the art before Raphael was more sincere, more true to nature and how we see, and therefore less formulaic. These artists also embraced a wide range of subjects, including modern life, biblical and literary subjects, and even history. By looking backwards, the Pre-Raphaelites led British art into the modern era.", 
                                    "id": "pre-raphaelites", 
                                    "title": "Pre-Raphaelites"
                                }, 
                                {
                                    "description": "British art saw a return to the classical after the 1860s, not just in terms of style, but also subject matter. Alma Tadema created sensual Victorian visions of the ancient Greeks and Romans, and Leighton too rendered classicizing figures and subjects. Both of these artists, together with Sargent, were influenced by the Aesthetic Movement, where the subject or narrative of a work of art was minimized in favor of a focus on issues of form (color harmonies, line, composition).", 
                                    "id": "late-victorian", 
                                    "title": "Late Victorian"
                                }, 
                                {
                                    "description": "In the mid-Nineteenth Century, great art was still defined as art that took it\u2019s subjects from religion, history or mythology and its style from ancient Greece and Rome. Hardly what we would consider modern and appropriate for an industrial, commercial, urban culture! Courbet agreed, and so did his friend, the writer Charles Baudelaire who called for an art that would depict, as he called it, the beauty of modern life. Courbet painted the reality of life in the countryside\u2014not the idealized peasants that were the usual fare at the exhibits in Paris. The revolution of 1848, in which both the working class and the middle class played a significant role, set the stage for Realism. Later, Manet and then Degas painted modern life in Paris, a city which was undergoing rapid modernization in the period after 1855 (the Second Empire).", 
                                    "id": "realism", 
                                    "title": "Realism"
                                }, 
                                {
                                    "description": "Despite the brief dismantling of the Royal Academy during the French Revolution, art remained an extension of the power of the French State which regularly purchased art that it favored (often art that supported its political objectives). Through the Royal Academy (originally been founded by Louis XIV), the state extended its reach to the official exhibitions (salons) and to matters of style and subject matter through the \u00c9cole des Beaux Arts (School of Fine Arts). These were not just the official institutions of art, they were, in essence, the only institutions available for living artists to train and to make their work known. This tutorial looks at a crucial moment for painting, on the eve of the Revolution of 1848. We also examine one of the great State commissions of the Second Empire, The Opera House, as well as The Dance, a sculpture that adorned its fa\u00e7ade.", 
                                    "id": "second-empire", 
                                    "title": "Art and the French state"
                                }, 
                                {
                                    "description": "Impressionism is both a style, and the name of a group of artists who did something radical\u2014in 1874 they banded together and held their own independent exhibition. These artists described, in fleeting sensations of light, the new leisure pastimes of the city and its suburbs It\u2019s hard to imagine, but at this time in France, the only place of consequence that artists could exhibit their work was the official government-sanctioned exhibitions (called salons), held just once a year, and controlled by a conservative jury. The Impressionists painted modern Paris and landscapes with a loose open brushstrokes, bright colors, and unconventional compositions\u2014none of which was appreciated by the salon jury!", 
                                    "id": "impressionism", 
                                    "title": "Impressionism"
                                }, 
                                {
                                    "description": "The work of van Gogh, Gauguin, C\u00e9zanne and Seurat together constitute Post-Impressionism and yet their work is so varied and unrelated, we might never otherwise think of these four artists as a group. Certainly van Gogh and Gauguin were friends and they briefly painted together, but each of these artists was concerned with solving particular issues that had to do with their own individual sensibility. Ironically, if anything ties these artists together it is this focus on subjectivity. This tutorial explores the sketchy multiperspectival views of C\u00e9zanne, Seurat\u2019s systematized critiques of upper middle-class Paris, Gauguin\u2019s fascination with the primitive and exotic, and van Gogh\u2019s unerring ability to convey deeply human experiences.", 
                                    "id": "post-impressionism", 
                                    "title": "Post-Impressionism"
                                }, 
                                {
                                    "description": "The 1880s saw a shift away from the modern-life focus of Impressionism, as artists turned toward the interior self, to dreams, and myth. There was a sense that Impressionism had been too tied up with the materialism of middle-class culture. In some ways, van Gogh and Gauguin can also be seen as Symbolists. Many Symbolist belonged to groups of artists who broke away (or seceded) from the art establishment in their respective countries, to hold their own exhibitions. For example, Klimt belonged to the Vienna Secession (he was its first president), Khnopff to a similar group in Belgium called Lex XX (The Twenty), and Stuck co-founded the Munich Secession.", 
                                    "id": "symbolism", 
                                    "title": "Symbolism & Art Nouveau"
                                }
                            ], 
                            "description": "The art of this period is familiar, since the world of the Realists, Impressionists and Post-Impressionists is much like our own. More and more people lived in cities and worked in factories or shops for wages. Scientific and technological advances increased dramatically during this period and although there was dislocation and privation, standards of living increased sharply. In essence, modern mass culture was born. Artists responded sometimes by embracing these radical changes, and at other times by resisting them. Key here is understanding the authority of the various art academies in Europe, which controlled matters related to taste and art, and which were, to some extent, always connected to the government. A small number of artists rebelled against the strictures of the academy, and against the demand for art to tell clear stories for a middle class audience, and formed what we know as the \u201cavant-garde.\u201d", 
                            "id": "art-history-1848-1907-industrial-revolution-ii", 
                            "title": "1848-1907 Industrial Revolution II"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Why is that art? Can art be an idea? Does art have to represent the world we see?", 
                                    "id": "big-questions-modern-contemporary-art", 
                                    "title": "Big Questions in Modern & Contemporary Art"
                                }, 
                                {
                                    "description": "Wild Beasts! Les Fauve (wild beasts) is what one critic called the brilliant expressive canvases of Matisse and other artists who exhibited together in 1905. This tutorial traces the work of Henri Matisse from his early Fauvist work with its jarringly bright colors to the stricter geometries he introduced during the First World War. It also tracks Expressionist developments in Germany and Austria with videos on Kirchner, Kandinsky and Jawlensky, artists who adopted a rough, \u201cprimitive\u201d style, and on Egon Schiele\u2019s taut, sexually charged paintings from Vienna.", 
                                    "id": "expressionism", 
                                    "title": "Expressionism"
                                }, 
                                {
                                    "description": "The Spaniard Picasso changed the way we see the world. He could draw with academic perfection at a very young age but he gave it up in order to create a language of representation suited to the modern world. Together with the French artist George Braque, Picasso undertook an analysis of form and vision that would inspire radical new visual forms across Europe and in America. This tutorial explains the underlying principles of Cubism and the abstract experiments that followed including Italian Futurism, Russian Suprematism, and the Dutch movement, de Stijl.", 
                                    "id": "cubism", 
                                    "title": "Cubism and its impact"
                                }, 
                                {
                                    "description": "Do we know who we really are? What parts of our mind do we know and what parts are hidden from us? Should art only focus on the rational, the conscious, or should we also pay attention to the irrational, the uncanny, the powerful impulses that remain unarticulated and just beyond the reach of our awareness. Dada was born during WWI when poets, artists, and actors, sickened by the violence around them, chose to celebrate the irrational. They created an anti-art that challenged the cultural assumptions that they felt supported the ruling elite that had, in turn, caused the war. In the years after the war, Dada gave way to Surrealism which reinstituted traditional forms of art-making but focused on Freud\u2019s theories of the unconscious.", 
                                    "id": "dada", 
                                    "title": "Dada & Surrealism"
                                }, 
                                {
                                    "description": "Germany was defeated and exhausted in 1918 at the end of WWI. The equally exhausted victors imposed harsh terms on Germany. It was forced to forfeit its overseas colonial possessions, to cede land to its neighbors, and to pay reparations. As demobilized troops returned, German cities filled with unemployed, often maimed veterans. The Socialists briefly seized power and by the early 1920s hyperinflation further destabilized the nation. Neue Sachlichkeit or the New Objectivity cast a cold sharp eye on Modern Germany\u2019s hypocrisy, aggression, and destitution even as extremists on the political right consolidated power. The National Socialists or Nazi Party won the chancellorship in 1933 and quickly used art and architecture as a means build the myth of a pure German people shaped by the land and unsullied by modern industrial culture. This tutorial looks at the ways that competing political ideologies each used art for its own purposes.", 
                                    "id": "neue-sachlichkeit", 
                                    "title": "German art between the wars"
                                }, 
                                {
                                    "description": "Towers of glass and steel from the mid-20th Century suggest, for many people, the rationalization of urban space that dehumanized our cities with empty plazas, rigorous geometries and uniformity. But International style architecture was born of the utopian idea that innovative design could improve the lives millions and its forms recall the clarity and harmony of ancient Greek architecture. This tutorial treats the late work of Ludwig Mies van der Rohe, Gordon Bunshaft, and Frank Lloyd Wright.", 
                                    "id": "architecture", 
                                    "title": "International style architecture"
                                }, 
                                {
                                    "description": "Artists in Mexico and other parts of Latin America including Cuba and Chile produced some of the most advanced art of the modern period. Wilfredo Lam, Frida Kahlo, Diego Rivera, Jos\u00e9 Orozco, and others drew on European modernist experiments like Cubism and Surrealism, as well as indigenous traditions, to tackle the political and social revolutions that transformed their nations.", 
                                    "id": "latin-american-modernism", 
                                    "title": "Latin American Modernism"
                                }, 
                                {
                                    "description": "Art had never been especially important in America. Before the Civil War, many of America\u2019s best artists went to Europe and stayed. Even after the war, American artists found little enthusiasm for their work unless it was directly informed by European precedents. By the first years of the 20th Century, a small group of American artists began to paint the gritty streets of New York and were called the Ashcan School for their portrayal of life in the tenements. In 1913 however, the Armory Show exhibited advanced American and European art and helped to create a market for the work of Georgia O\u2019Keeffe and other members of modern galleries like Alfred Steiglitz\u2019s 291 and Peggy Guggenheim\u2019s Art of This Century. During the Great Depression artists such as Grant Wood portrayed rural life in the south and midwest and became known as regionalists while other realists such as Edward Hopper rendered the alienation of the modern city. Meanwhile, Surrealist ideas infused a younger generation of artists\u2019 work in Mexico and the US which would result, by the end of WWII, in the first internationally important American art movement, Abstract Expressionism.", 
                                    "id": "American Modernism", 
                                    "title": "American Modernism"
                                }
                            ], 
                            "description": "Europe in 1907 was powerful, wealthy and stable. The British Empire was unmatched with huge territories that stretched across the globe. The Austrian-Hungarian and Ottoman Empires remained intact, and the Italians, Germans, Dutch, Spanish and Portuguese retained colonies. Nevertheless, the old order would soon collapse, a result of the Great War in 1914. But this trauma was only the beginning. A global financial collapse precipitated by the stock market crash of 1929 allowed Mussolini, Franco and Hitler to seize power. The violence only worsened with the Holocaust, Japanese Imperial expansion, and the Second World War.\n\nAt the same time, this was a period of radical advances in music (Stravinsky, Bartok, etc.), in dance (Duncan, Graham, etc.) in literature (Joyce, Pound, etc.), science (Einstein, Heisenberg, etc.), and of course, in art (Matisse, Picasso, etc.). In the years between the wars artists explored abstraction and the irrational. After the war, and with Europe in ruins, the focus of the art world shifted from Paris to New York where Abstract Expressionism was born.", 
                            "id": "art-history-1907-1960-age-of-global-conflict", 
                            "title": "1907-1960 Age of Global Conflict"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Artists first represented the human body more than 30,000 years ago and haven\u2019t stopped since. Figurative art has been a continuous tradition through human history. Even in societies where the biblical law forbidding the graven image is most strictly interpreted (Judaism and Islam for example), there have always been instances of figural art. The same is true for the era of modernist abstraction when artists found new ways to portray the body on canvas or with the lens of a camera that could profoundly describe the human condition in , and abstraction the post-holocaust era.", 
                                    "id": "the-postwar-figure", 
                                    "title": "The postwar figure"
                                }, 
                                {
                                    "description": "When people walk into an art museum they often expect to see treasures of their cultural history\u2014beautifully crafted precious objects that express profound truths\u2014images of God, nature, man\u2019s heroism, but Campbell soup cans hawked on TV? Pop art sought to upend our comfortable understanding of what art is and it did just that. Warhol, Lichtenstein, Oldenburg, and others confronted the visual reality of our commercial consumer culture by focusing on the mechanics of representation and the subject matter of daily life in the middle of the 20th Century.", 
                                    "id": "pop-art", 
                                    "title": "Pop & After"
                                }, 
                                {
                                    "description": "\u201cPrimary Structures,\u201d \u201cABC Art,\u201d and \u201cMinimalism\u201d are terms that attempted to categorize the work of Donald Judd, Dan Flavin, Sol Lewitt and other artists who produced hard edged, often geometric and seemingly machined objects in the later 1960s and early 1970s. These stark, often cold and cerebral forms were the very antithesis of the deeply emotive gestural art of the Abstract Expressionists and their followers who had dominated the New York art scene since the 1940s. Here was an art that renounced the authentic \u201chand\u2019 of the artist and sought instead to create forms without reference to the world beyond the object\u2019s own logic except perhaps as Platonic expressions of a pure ideal.", 
                                    "id": "minimalism", 
                                    "title": "Minimalism and the land"
                                }, 
                                {
                                    "description": "By the second half of the 20th Century, the avant-garde had an avant-garde of its own. Even as Pop, Minimal and Concept artists renounced the handmade work of art, a small group of women recognized the subversive value of handicraft in an age of industrial manufacturing and in an art world dominated by male artists and critics who sought theoretical purity. During her short career, Eva Hesse resituated the ancient question of how to meaningfully represent the human body and unleashed decades of experimentation that continues to this day. Judy Chicago, Linda Benglis, Jackie Windsor, Faith Ringgold, and others used the lowly status of craft and its historical association with female artisans to contrast with \u201chigh art.\u201d By focusing of the act of making, on process and craft, these women began the process of fracturing Modernism\u2019s reductive and largely male narratives.", 
                                    "id": "process-art", 
                                    "title": "Process art"
                                }, 
                                {
                                    "description": "Can art be an enactment? Can the \u201cart\u201d be relocated from the object crafted by an artist to the more ephemeral reaction of the viewer? Must an artist actually \u201cmake\u201d a work of art at all? Conceptual artists recognized that when the 19th Century avant-garde broke with the academies and their emphasis on technical execution (the blending color or compositional clarity for example), they were freer to focus on more conceptual issues such as modern urban life, subjectivity, or pictorial language. Fast forward to the second half of the Twentieth Century when intellectual content became the defining characteristic of art and concept fully eclipsed craft. In the 1960 and 70s the art of Beuys, Haacke and others became increasingly conceptual. These artists used found objects, performance, and installation while de-emphasizing the act of \u201cobject making.\u201d", 
                                    "id": "performance-art", 
                                    "title": "Conceptual art"
                                }, 
                                {
                                    "description": "If you\u2019ve done the tutorials on Nineteenth and Twentieth Century art then you likely have an idea that by \u201cModernism,\u201d art historians are referring to a set of ideas that characterize art and culture after about 1848. Key to understanding Modern art are the ideas of a heroic \u201cavant-garde\u201d that challenges authority and the expression of the individual (one that is invariably white and male). The term \u201cPost-Modernism,\u201d was initially used in the art world in 1979 for architecture that arbitrarily borrowed historical styles with little regard for original meaning or context. The term was quickly and broadly adopted, and came to refer to a strategy to undermine Modernism\u2019s utopian and heroizing tendencies by using multiple yet simultaneous critical perspectives. Post-Modernism was not anti-Modernism, it was instead, an effort to destabilize Modernist narratives with deeply skeptical critical strategies that emphasized the plurality of gender, race, nationality, politics, and economic inequality.", 
                                    "id": "postmodernism", 
                                    "title": "Postmodernism"
                                }, 
                                {
                                    "description": "Art of the past half century that focuses on the body and its meanings through depiction and enactment outside the traditional boundaries of dance, drama and music.", 
                                    "id": "Performance-art-tutorial", 
                                    "title": "The body as subject and medium"
                                }, 
                                {
                                    "description": "Architecture has changed radically in the past fifty years as computers have allowed designers to shape space in ways that had never been possible before and as design theory has transformed the ways in which we conceive of the built environment.", 
                                    "id": "Contemporary-Architecture", 
                                    "title": "Contemporary Architecture"
                                }
                            ], 
                            "description": "By 1960, the unprecedented violence of the first half of the century had ebbed, replaced by the Cold War and threat of nuclear catastrophe. The vacuum left by European powers as they withdrew from their colonies instigated a global power grab as small nations sought autonomy but became proxies in a global strategic confrontation between Western and Soviet or Chinese ideologies. \n\nAt the same time protest movements in the West called for an end to war, racism, and gender inequality. Powerful, entrenched conservative institutions such as the Catholic Church were transformed. The assassinations of John F. Kennedy and Martin Luther King Jr., coupled later with Watergate, created a deep distrust for institutional authority. Artists responded by producing exceptionally thoughtful, original and provocative work that became increasingly global in its perspective.", 
                            "id": "art-history-1960---age-of-post-colonialism", 
                            "title": "1960 -  Age of Post-Colonialism"
                        }
                    ], 
                    "description": "We understand the history of humanity through art.  From prehistoric depictions of wooly mammoths to contemporary abstraction, artists have addressed their time and place in history and have expressed universal human truths for tens of thousands of years. Learn what made Rome great, how Islamic tile work evolved, why the Renaissance happened, and about the brilliant art being produced today around the globe. \nDr. Beth Harris and Dr. Steven Zucker, together with leading art historians, have created hundreds of short engaging conversational videos and articles,  making Khan Academy one of the most accessible and extensive resources for the study of the history of art. Come with us to the Louvre, to a church in Rome, and to a mosque in Istanbul so that you can experience the art up close and on location.\n\nAlso maintained at http://smarthistory.khanacademy.org/.", 
                    "id": "art-history", 
                    "title": "Art history"
                }, 
                {
                    "children": [
                        {
                            "description": "Videos about how government works in the United States.", 
                            "id": "american-civics", 
                            "title": "American civics"
                        }
                    ], 
                    "description": "Videos about how government works in the United States.", 
                    "id": "american-civics-subject", 
                    "title": "American civics"
                }, 
                {
                    "children": [
                        {
                            "description": "The basic principles of music are explained in plain language with helpful graphics and live video demonstrations. If you have ever wondered \"how does music work?\" then you'll find answers here. Presented by the All-Star Orchestra music director Gerard Schwarz. ", 
                            "id": "music-basics-notes-rhythm-music", 
                            "title": "Music basics: Notes and rhythm"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Possibly the most iconic of all symphonies, \"Beethoven's 5th\" is instantly recognizable by its dramatic opening motive. Learn how this rhythmic and melodic idea permeates the entire work, holding the listener in thrall through all four movements to the blazing finale. Music Director Gerard Schwarz and noted expert Leon Botstein explore the many facets of Beethoven's masterpiece, including a demonstration by Maestro Schwarz of how to conduct the first movement.", 
                                    "id": "ludwig-van-beethoven-music", 
                                    "title": "Ludwig van Beethoven: Symphony No. 5"
                                }, 
                                {
                                    "description": "", 
                                    "id": "antonin-dvorak-music", 
                                    "title": "Anton\u00edn Dvo\u0159\u00e1k: Symphony No. 9 \"From the New World\""
                                }, 
                                {
                                    "description": "", 
                                    "id": "igor-stravinsky-music", 
                                    "title": "Igor Stravinsky: Suite from The Firebird"
                                }, 
                                {
                                    "description": "Analysis by Gerard Schwarz. A love story from ancient Greek mythology inspired the creation of an epic ballet in 1912. French composer Maurice Ravel expanded the possibilities of orchestral color and texture in his remarkable score. Music Director Gerard Schwarz explores the history and musical structure of this landmark work of musical Impressionism.", 
                                    "id": "maurice-ravel-music", 
                                    "title": "Maurice Ravel: Suite No. 2 from Daphnis et Chloe"
                                }, 
                                {
                                    "description": "A leading composer of her generation, Augusta Read Thomas' works have been performed by major orchestras around the world. Here she discusses the compositional process that led to Of Paradise and Light. Music Director Gerard Schwarz joins in the discussion of this transcendent new work.", 
                                    "id": "augusta-read-thomas-music", 
                                    "title": "Augusta Read Thomas: Of Paradise and Light"
                                }, 
                                {
                                    "description": "Pulitzer-prize-winning composer and Harvard Professor of Music Bernard Rands discusses the art of composition. He and Music Director Gerard Schwarz look into the score of Rands' recent work \"Adieu\"  (\"Goodbye\") as recorded by the All-Star Orchestra.", 
                                    "id": "bernard-rands-music", 
                                    "title": "Bernard Rands: Adieu"
                                }
                            ], 
                            "description": "Discover what makes a masterpiece by learning how classical works are composed. Music Director Gerard Schwarz explains the history, context and compositional techniques behind famous orchestral works, from Beethoven to leading composers of the present day.", 
                            "id": "music-masterpieces-old-new", 
                            "title": "Masterpieces old and new"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "The largest group within the orchestra is comprised of instruments that produce sound from vibrating strings. The vibrations \u2013 resulting from the strings being played by a bow, or being plucked with the fingers \u2013 resonate within the body of each instrument. The violin, viola, cello and contrabass are all primary played with a bow. The harp is  plucked and stroked with the hands. Principals from the All-Star Orchestra introduce the special qualities and histories of each instrument.", 
                                    "id": "strings-music", 
                                    "title": "Strings"
                                }, 
                                {
                                    "description": "This family of instruments is situated in the middle of the orchestra, and is comprised of three groups: the flutes (flutes, piccolo), single reeds (clarinets, bass-clarinet), and double reeds (oboe, English horn, bassoons, contra-bassoon) Watch and listen as principal players of the All-Star Orchestra demonstrate their instruments and tell about their musical lives. ", 
                                    "id": "woodwinds-music", 
                                    "title": "Woodwinds"
                                }, 
                                {
                                    "description": "Each of the instruments in this family are made to sound by the vibrations of the player's lips combined with a steady stream of breath. Learn from the All-Star Orchestra players themselves about the special attributes of the trumpet, French horn, trombone, bass trombone and tuba.", 
                                    "id": "brass-music", 
                                    "title": "Brass"
                                }, 
                                {
                                    "description": "This large family, including timpani, drums, cymbals, xylophones, gongs, bells, and rattles, is comprised of  musical instruments played by striking with the hand or with a stick or beater, or by shaking or rubbing.  The All-Star Orchestra percussion section demonstrates the remarkable variety of sounds that can be produced. Also included in this group are orchestral keyboard instruments like the piano and celesta.", 
                                    "id": "percussion-music", 
                                    "title": "Percussion"
                                }
                            ], 
                            "description": "Learn about the different instruments of the orchestra as they are presented and demonstrated by  principal players from famous symphony orchestras.", 
                            "id": "music-instruments-orchestra", 
                            "title": "Instruments of the orchestra"
                        }
                    ], 
                    "description": "An exploration of classical music as a living tradition. Top orchestral players from across the United States meet once-a-year in New York as the All-Star Orchestra to record masterpieces and new works with Music Director Gerard Schwarz. Come behind the scenes, meet the musicians, attend an open rehearsal, gain a conductor's perspective, and have a first-person encounter with the music.", 
                    "id": "music", 
                    "title": "Music"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "The critical thinking section will teach you the skills to think clearly and independently. It will help you identify valid arguments, detect inconsistencies in reasoning, understanding logical connections between ideas, and construct and evaluate arguments.", 
                                    "id": "criticalthinking", 
                                    "title": "Critical thinking"
                                }, 
                                {
                                    "description": "Metaphysics is an area of philosophy concerned with what there is in the universe (ontology) and the nature of what exists. Epistemology is a related area interested in knowledge and how we know things about the universe.", 
                                    "id": "metaphysics-epistemology", 
                                    "title": "Metaphysics and epistemology"
                                }, 
                                {
                                    "description": "Value theory is an evaluative area of philosophy that includes ethics, aesthetics, social and political philosophy, feminist philosophy, and other areas.", 
                                    "id": "value-theory", 
                                    "title": "Value theory"
                                }, 
                                {
                                    "description": "Are you interested in learning more about what philosophers have said in the past? Check out this section to learn more about the history of philosophical thought.", 
                                    "id": "history-of-philosophy", 
                                    "title": "History of philosophy"
                                }
                            ], 
                            "description": "Wi-Phi introduces people to the practice of philosophy by making videos that are entertaining, interesting, and accessible to people with no background in the subject. Wi-Phi is run by Gaurav Vazirani and a team of dedicated graduate students who collaborate with some of the best philosophers in the world to produce the videos at www.wi-phi.com.", 
                            "id": "philosophy-wi-phi", 
                            "title": "Philosophy: Wi-Phi"
                        }
                    ], 
                    "description": "", 
                    "id": "philosophy", 
                    "title": "Philosophy"
                }
            ], 
            "description": "", 
            "id": "humanities", 
            "title": "Arts and humanities"
        }, 
        {
            "children": [
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "Explore how we have hidden secret messages through history.", 
                                    "id": "crypt", 
                                    "title": "Ancient cryptography"
                                }, 
                                {
                                    "description": "Learn about algorithms for performing encryption & decryption. Then practice making and breaking codes!", 
                                    "id": "ciphers", 
                                    "title": "Ciphers"
                                }, 
                                {
                                    "description": "A new problem emerges in the 20th century. What happens if Alice and Bob can never meet to share a key in the first place?", 
                                    "id": "modern-crypt", 
                                    "title": "Modern cryptography"
                                }, 
                                {
                                    "description": "This is a system of arithmetic for integers. These lessons provide a foundation for the mathematics presented in the Modern Cryptography tutorial.", 
                                    "id": "modarithmetic", 
                                    "title": "Modular arithmetic"
                                }, 
                                {
                                    "description": "Why do Primes make some problems fundamentally hard? Build machines to perform primality tests!", 
                                    "id": "comp-number-theory", 
                                    "title": "Primality test"
                                }, 
                                {
                                    "description": "Would access to coin flips speed up a primality test? How would this work?", 
                                    "id": "random-algorithms-probability", 
                                    "title": "Randomized algorithms"
                                }
                            ], 
                            "description": "How have humans protected their secret messages through history? What has changed today?", 
                            "id": "cryptography", 
                            "title": "Journey into cryptography"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "The first challenge in the Cryptography series", 
                                    "id": "cryptochallenge", 
                                    "title": "Cryptography challenge 101"
                                }
                            ], 
                            "description": "Solve problems using Mathematics, Computer Science and more!", 
                            "id": "applied_math_challenges", 
                            "title": "Challenges"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Explore the history of communication from signal fires to the Information Age", 
                                    "id": "info-theory", 
                                    "title": "Ancient information theory"
                                }, 
                                {
                                    "description": "Information Theory in the 20th Century", 
                                    "id": "moderninfotheory", 
                                    "title": "Modern information theory"
                                }
                            ], 
                            "description": "We've always been communicating.... as we moved from signal fires, to alphabets & electricity the problems remained the same.", 
                            "id": "informationtheory", 
                            "title": "Journey into information theory"
                        }
                    ], 
                    "description": "Learn select topics from computer science - cryptography (how we protect secret information) and information theory (how we encode and compress information).", 
                    "id": "computer-science", 
                    "title": "Cryptography & information theory"
                }
            ], 
            "description": "", 
            "id": "computing", 
            "title": "Computing"
        }, 
        {
            "children": [
                {
                    "children": [
                        {
                            "description": "", 
                            "id": "overview-sat-prep", 
                            "title": "Overview of SAT prep on Khan Academy"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "In section 2, you'll zero in on math practice with a bunch of math problems from a real SAT. \nWant even more math practice? Check out sections 6 and 8 and the SAT Math practice topic.", 
                                    "id": "SAT-test1-section2", 
                                    "title": "Section 2"
                                }, 
                                {
                                    "description": "In Section 3, let's switch gears and focus on Reading questions, starting on pg. 48 of the downloadable SAT.\nWant even more reading practice? Check out the SAT Reading and Writing practice topic.\n", 
                                    "id": "SAT-test1-section3", 
                                    "title": "Section 3"
                                }, 
                                {
                                    "description": "Have you ever seen a sentence in a newspaper or on a restaurant menu that just wasn't quite right? In this section, you'll have lots of opportunities to find errors and fix 'em. \nSection 5 starts on pg. 54 of the downloadable test.\n\nWant even more writing practice? Check out the SAT Reading and Writing practice topic.", 
                                    "id": "SAT-test1-section5", 
                                    "title": "Section 5"
                                }, 
                                {
                                    "description": "There are some really fun math problems in this section. Seriously. It all begins on pg. 60 in the downloadable SAT.\n\nWant even more math practice? Check out sections 2 and 8 and the SAT Math practice topic.", 
                                    "id": "SAT-test1-section6", 
                                    "title": "Section 6"
                                }, 
                                {
                                    "description": "More math practice coming your way in Section 8, starting on pg. 69 in the downloadable SAT.\n\nWant even more math practice? Check out sections 2 and 6 and the SAT Math practice topic.", 
                                    "id": "SAT-test1-section8", 
                                    "title": "Section 8"
                                }
                            ], 
                            "description": "Download and take a real, full-length practice test. Watch videos showing step-by-step solutions to problems you missed or found challenging, and get even more practice with unreleased questions from real SATs provided by College Board. \n\nAfter all that practice, it wouldn't hurt to take the full-length test again so you can get used to the feeling of answering all of the questions correctly. Rock on!", 
                            "id": "full-length-SAT-1", 
                            "title": "Full-length SAT"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "In this tutorial, you'll find the SAT Math Practice: Level 1 exercise, featuring lots of previously-unreleased SAT math questions provided by College Board. Stuck on a problem? Check out videos where Sal solves each problem step by step. Let's do this!", 
                                    "id": "sat-math-level-1", 
                                    "title": "SAT Math: Level 1"
                                }, 
                                {
                                    "description": "In this tutorial, you'll find the SAT Math Practice: Level 2 exercise, featuring lots of previously-unreleased SAT math questions provided by College Board. Stuck on a problem? Check out videos where Sal solves each problem step by step. Here we go!", 
                                    "id": "sat-math-level-2", 
                                    "title": "SAT Math: Level 2"
                                }, 
                                {
                                    "description": "In this tutorial, you'll find the SAT Math Practice: Level 3 exercise, featuring lots of previously-unreleased SAT math questions provided by College Board. Stuck on a problem? Check out videos where Sal solves each problem step by step. Congrats on venturing into level 3 territory. You've got this!", 
                                    "id": "sat-math-level-3", 
                                    "title": "SAT Math: Level 3"
                                }, 
                                {
                                    "description": "In this tutorial, you'll find the SAT Math Practice: Level 4 exercise, featuring lots of previously-unreleased SAT math questions provided by College Board. Stuck on a problem? Check out videos where Sal solves each problem step by step. You're tackling some of the harder SAT Math problems now. Rock it out!", 
                                    "id": "sat-math-level-4", 
                                    "title": "SAT Math: Level 4"
                                }, 
                                {
                                    "description": "In this tutorial, you'll find the SAT Math Practice: Level 5 exercise, featuring lots of previously-unreleased SAT math questions provided by College Board. Stuck on a problem? Check out videos where Sal solves each problem step by step. These are the hardest math problems on the SAT. Eye of the tiger!", 
                                    "id": "sat-math-level-5", 
                                    "title": "SAT Math: Level 5"
                                }
                            ], 
                            "description": "In these tutorials, you'll get the chance to practice solving tons of real, previously-unreleased SAT Math problems provided by College Board.\n\nThe exercises are split by difficulty level on the SAT and accompanied by short videos showing one way to solve each problem. \n\nOnward!", 
                            "id": "sat-math-practice", 
                            "title": "SAT Math practice"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "SAT-writing-id-sentence-errors", 
                                    "title": "SAT Writing: Identifying sentence errors"
                                }, 
                                {
                                    "description": "", 
                                    "id": "SAT-reading-sentence-completion", 
                                    "title": "SAT Reading: Sentence completion"
                                }
                            ], 
                            "description": "In these tutorials, you'll get the chance to practice with tons of real, previously-unreleased SAT Reading and Writing problems provided by College Board.\n\nYou'll find exercises on three of the SAT Reading and Writing question types: sentence completion, identifying sentence errors, and improving sentences.\n\nOnward!", 
                            "id": "sat-reading-writing-practice", 
                            "title": "SAT Reading and Writing practice"
                        }
                    ], 
                    "description": "If you\u2019re taking the SAT soon, you can start preparing today with questions from real SATs. After all, we believe all students who want to go to college should be able to prepare for the SAT at their own pace, at absolutely no cost. \n\nDownload a real, full-length SAT practice test, watch Sal work through real SAT problems, and get even more practice using our interactive exercises, which feature tons of previously-unreleased problems from real SATs grouped by topic and difficulty level.\n\nIf you feel like you need to brush up on fundamentals, check out the Algebra mission, which will help you master core concepts covered on the SAT, in college, and beyond at your own pace.\n\nIf you\u2019re taking the SAT in 2016 or later, we have even more exciting news for you. The College Board just announced that they\u2019re redesigning the SAT for 2016, and we\u2019re partnering with them to make free, world-class prep materials. By spring 2015, you\u2019ll have access to state-of-the-art learning tools--exercises, software diagnostics and videos--designed by Khan Academy and College Board specifically for the redesigned SAT. Stay tuned! ", 
                    "id": "sat", 
                    "title": "SAT"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "1A: What is the central dogma of biology?  Learn the fundamental relationships that tie together DNA, RNA, and proteins.  Then go on to discover the different types of amino acids, and how they come together to form complex proteins.  By Tracy Kim Kovach.", 
                                    "id": "amino-acids-and-proteins1", 
                                    "title": "Amino acids and proteins"
                                }, 
                                {
                                    "description": "1A: Learn the basics of enzyme structure and function. Enzymes are able to catalyze lots of different biochemical reactions, and make them occur at much faster rates.  By Ross Firestone.", 
                                    "id": "enzyme-structure-and-function", 
                                    "title": "Enzyme structure and function"
                                }, 
                                {
                                    "description": "1A: Come learn about enzyme kinetics. How can we look at enzyme activity from a mathematical point of view?  By Ross Firestone.", 
                                    "id": "enzyme-kinetics", 
                                    "title": "Enzyme kinetics"
                                }, 
                                {
                                    "description": "1B: Learn about gene expression and how information flows between DNA and protein.  By Tracy Kim Kovach.", 
                                    "id": "dna", 
                                    "title": "DNA"
                                }, 
                                {
                                    "description": "1B: Regulation of genes occurs at every step of the pathway for gene expression. Gene control is critical to the health of the cell, especially with regards to oncogenes and tumor suppressor genes.  By Tracy Kim Kovach.", 
                                    "id": "gene-control", 
                                    "title": "Gene control"
                                }, 
                                {
                                    "description": "1C: Come learn about what mutations are, where they come from, and how they change the cells they affect. By Ross Firestone.", 
                                    "id": "genetic-mutations", 
                                    "title": "Genetic mutations"
                                }, 
                                {
                                    "description": "1C: How do organisms evolve from one form to another? Learn about all of the different driving forces of evolution and how there might be a few more than just natural selection. How can populations evolve and adapt to changes in their environment? Do groups of organisms behave differently than individuals?  By Ross Firestone.", 
                                    "id": "evolution-population-dynmaics", 
                                    "title": "Evolution and population dynamics"
                                }, 
                                {
                                    "description": "1D: What are the thermodynamic principles that are fundamental to understanding metabolism? Learn about Gibbs Free Energy, Enthalpy, and Le Chatelier's Principle.  By Jasmine Rana.", 
                                    "id": "principles-of-bioenergetics", 
                                    "title": "Principles of bioenergetics"
                                }, 
                                {
                                    "description": "1D: What is metabolism? What molecules are involved? How is useful chemical energy produced? Apply principles from general chemistry and biology to learn the common themes of metabolism.  By Jasmine Rana.", 
                                    "id": "overview-metabolism", 
                                    "title": "Overview of metabolism"
                                }, 
                                {
                                    "description": "1D: What are the key metabolic pathways that are intimately involved in breaking down or building up glucose? Learn about glycolysis, gluconeogenesis, and the pentose phosphate pathway and how they fit into cellular respiration as a whole.  By Jasmine Rana.", 
                                    "id": "carbohydrate-metabolism", 
                                    "title": "Carbohydrate Metabolism"
                                }, 
                                {
                                    "description": "1D: What are the key metabolic pathways involved in fat and protein metabolism? Learn about the concepts of energy storage, fatty acid synthesis, fatty acid oxidation, ketone synthesis, and amino acid metabolism.  By Jasmine Rana.", 
                                    "id": "fat-and-protein-metabolism", 
                                    "title": "Fat and protein metabolism"
                                }, 
                                {
                                    "description": "1D: Learn about two of the most vital energy-producing pathways that take place in the mitochondria: The Krebs/TCA cycle and oxidative phosphorylation in the electron transport chain.  Learn about the products and reactants of these pathways and how they are regulated.  By Jasmine Rana.", 
                                    "id": "Krebs-citric-acid-cycle-and-oxidative-phosphorylation", 
                                    "title": "Krebs (citric acid) cycle and oxidative phosphorylation"
                                }, 
                                {
                                    "description": "", 
                                    "id": "mendelian-genetics", 
                                    "title": "Mendelian genetics"
                                }
                            ], 
                            "description": "Foundational Concept 1: Biomolecules have unique properties that determine how they contribute to the structure and function of cells, and how they participate in the processes necessary to maintain life.", 
                            "id": "biomolecules", 
                            "title": "Biomolecules"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "2A: Learn about the basics behind the cell membrane. What makes up the cell membrane and how does it work? How does our cell membrane help sustain life?  By William Tsai.", 
                                    "id": "cell-membrane-overview", 
                                    "title": "Cell membrane overview"
                                }, 
                                {
                                    "description": "", 
                                    "id": "cell-cell-interactions", 
                                    "title": "Cell-cell Interactions"
                                }
                            ], 
                            "description": "Foundational Concept 2: Highly-organized assemblies of molecules, cells, and organs interact to carry out the functions of living organisms", 
                            "id": "cells", 
                            "title": "Cells"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "3A: Get an overview of the structure and function of neurons, and learn about the many other important cells needed to help our nervous system function optimally!  By Matt Jensen.", 
                                    "id": "neural-cells", 
                                    "title": "Neural cells"
                                }, 
                                {
                                    "description": "3A: Learn the causes and functions of neuron membrane potentials, including resting, graded, and action potentials.  By Matt Jensen.", 
                                    "id": "neuron-membrane-potentials", 
                                    "title": "Neuron membrane potentials"
                                }, 
                                {
                                    "description": "3A: An overview of how neurons communicate with their target cells at synapses, and the roles of neurotransmitters and their receptors.  By Matt Jensen.", 
                                    "id": "neural-synapses", 
                                    "title": "Neuronal synapses"
                                }, 
                                {
                                    "description": "3A: Dive into the endocrine system! See how the body uses special organs (called glands) that secrete chemical messages (called hormones) in order to properly respond to it's changing environment.  By Ryan Patton.", 
                                    "id": "endocrine-system", 
                                    "title": "Endocrine system"
                                }, 
                                {
                                    "description": "3B: Learn about how the heart pumps blood throughout the body. Find out how blood vessels are organized. Understand how blood gets oxygen to the tissues, and then how it gets back to the lungs to absorb more oxygen.", 
                                    "id": "the-circulatory-system", 
                                    "title": "Circulatory system"
                                }, 
                                {
                                    "description": "3B: Find out why we need to breathe and how we manage to do it.  Air moves in and out of our lungs throughout the day and while we're sleeping.  Find out how we control this important process.", 
                                    "id": "the-respiratory-system", 
                                    "title": "Respiratory system"
                                }, 
                                {
                                    "description": "3B: Welcome to the lymphatic system! Learn about how it is a critical part of the circulatory system. Find out how it comes to the rescue of the cardiovascular system and the immune system. Also discover how it moves fluid in one direction, like blood, but without a heart!  By Patrick van Nieuwenhuizen.", 
                                    "id": "lymphatic-system", 
                                    "title": "Lymphatic system"
                                }, 
                                {
                                    "description": "3B: Discover your body's arsenal of weapons against invaders, like bacteria and viruses. Find out which different kinds of cells are involved, and how they work.", 
                                    "id": "the-immune-system", 
                                    "title": "Immune system"
                                }, 
                                {
                                    "description": "3B: Learn how the kidneys take blood and very selectively extract waste from it to expel from the body as urine.", 
                                    "id": "the-renal-system", 
                                    "title": "Renal system"
                                }, 
                                {
                                    "description": "3B: Learn how the kidneys vary our salt and water content to regulate our blood pressure.", 
                                    "id": "renal-regulation-of-blood-pressure", 
                                    "title": "Renal regulation of blood pressure"
                                }, 
                                {
                                    "description": "3B: Understand how we digest food from the second it enters our mouth to the moment it ends up in the bathroom. Learn how the Gastrointestinal Tract is perfectly designed to digest food and extract nutrients for our bodies to use.  By Raja Narayan.", 
                                    "id": "the-gastrointestinal-system", 
                                    "title": "Gastrointestinal system"
                                }, 
                                {
                                    "description": "3B: How do our muscles work? When we decide to kick a ball or shake a leg, how do we get our bodies to do that? Which muscles do we control? Which muscles control us? Learn how our muscles work at the smallest, most cellular level. Then see how nature scales up those microscopic processes into a kick or a dance move. Finally, learn how our brain tells muscle to contract and how that helps us respond to changes in temperature or even a lion chasing us.  By Raja Narayan.", 
                                    "id": "muscular-system", 
                                    "title": "Muscular system"
                                }, 
                                {
                                    "description": "3B: The skeletal system plays numerous vital roles in the human body. Learn about the structure and function of bones and the skeleton, as well as the endocrine control of the skeletal system.", 
                                    "id": "the-skeletal-system", 
                                    "title": "Skeletal system"
                                }
                            ], 
                            "description": "Foundational Concept 3: Complex systems of tissues and organs sense the internal and external environments of multicellular organisms, and through integrated functioning, maintain a stable internal environment within an ever-changing external environment.", 
                            "id": "organ-systems", 
                            "title": "Organ systems"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "4A: Find out what makes vectors different from scalars!  Find out how to break vectors into components, and go over the different ways to represent vectors.  By Sal.", 
                                    "id": "vectors-and-scalars", 
                                    "title": "Vectors and scalars"
                                }, 
                                {
                                    "description": "4A: Go back in time and rediscover Newton's three laws!  These powerful laws help explain inertia, equal and opposite forces, and calculation of acceleration based upon forces.  By Sal.", 
                                    "id": "newtons-laws-and-equilibrium", 
                                    "title": "Newton's laws and equilibrium"
                                }, 
                                {
                                    "description": "4A: Think to calculate speed and velocity, and then go on to learn about average and instantaneous speed and velocity.  By Sal and David SantoPietro.\n", 
                                    "id": "speed-and-velocity", 
                                    "title": "Speed and velocity"
                                }, 
                                {
                                    "description": "4A: Learn how to calculate acceleration, and how distance, velocity, and acceleration can be related to one another using velocity graphs.  By Sal.", 
                                    "id": "acceleration-mcat", 
                                    "title": "Acceleration"
                                }, 
                                {
                                    "description": "4A: Discover the force of tension and how we can use it to solve very interesting problems!  By Sal.", 
                                    "id": "force-of-tension", 
                                    "title": "Force of tension"
                                }, 
                                {
                                    "description": "4A: Learn about the normal force, and try some examples that demonstrate how the normal force is affected by the motion of an elevator, as well as how the normal force affects friction.  By Sal.", 
                                    "id": "normal-forces", 
                                    "title": "Normal forces"
                                }, 
                                {
                                    "description": "4A: Learn about the forces that an object experiences on a ramp or inclined plane. Examples include inclines with and without friction.  By Sal.", 
                                    "id": "forces-on-inclined-planes", 
                                    "title": "Forces on inclined planes"
                                }, 
                                {
                                    "description": "4A: Learn about the concepts of work, mechanical advantage, and power.  After understanding the principle of conservation of energy, you can apply it to different types of energy including kinetic energy, gravitational potential energy, and spring potential energy.  Finally, learn about the conservative force as well as how to find mechanical advantage.  By Sal and David SantoPietro.", 
                                    "id": "work-and-energy-mcat", 
                                    "title": "Work and energy"
                                }, 
                                {
                                    "description": "4B: Learn the physics behind fluids at rest. Some of the ideas explored are density, pressure, Pascal's principle, Archimedes' principle, buoyant forces, and specific gravity.  By Sal.", 
                                    "id": "fluids-at-rest", 
                                    "title": "Fluids at rest"
                                }, 
                                {
                                    "description": "4B: Let's learn about gas phase chemistry!  Discover the history and application of the ideal gas law. We'll walk through topics like temperature, STP, partial pressure, and the difference between real gases and their ideal counterparts.  By Ryan Patton.", 
                                    "id": "gas-phase", 
                                    "title": "Gas phase"
                                }, 
                                {
                                    "description": "4C: Learn how a capacitor works, and the mathematical formulas that explain their behavior.  By David Santo Pietro.", 
                                    "id": "capacitors", 
                                    "title": "Capacitors"
                                }, 
                                {
                                    "description": "4D: These videos go over the images formed by curved mirrors. It will be explained what a real and virtual image is and how to draw ray tracings to determine the location and size of the image formed. By David Santo Pietro.", 
                                    "id": "spherical-mirrors", 
                                    "title": "Spherical mirrors"
                                }, 
                                {
                                    "description": "4D: These videos describe the reflection and refraction of light rays. Topics discussed will include the different types of reflection, how to determine which way light bends, Snell's law, total internal reflection, and dispersion.  By David Santo Pietro and Sal Khan.", 
                                    "id": "reflection-and-refraction", 
                                    "title": "Reflection and refraction"
                                }, 
                                {
                                    "description": "4E: Discover how to assign oxidation states/numbers in redox reactions, then go on to balance redox reactions!  By Jay.", 
                                    "id": "redox-reactions", 
                                    "title": "Redox reactions"
                                }, 
                                {
                                    "description": "4E: Learn about how the periodic table is organized and then explore ionization energy and electron affinity.  By Jay.", 
                                    "id": "periodic-table-of-elements", 
                                    "title": "Periodic table"
                                }
                            ], 
                            "description": "Foundational Concept 4: Complex living organisms transport materials, sense their environment, process signals, and respond to changes using processes that can be understood in terms of physical principles.", 
                            "id": "physical-processes", 
                            "title": "Physical processes"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "5B: Learn how to draw Lewis dot structures, assign formal charges, draw resonance structures, and analyze the geometry of molecules and ions using VSEPR.  By Jay.", 
                                    "id": "dot-structures", 
                                    "title": "Dot structures"
                                }, 
                                {
                                    "description": "5B: Get an overview of isomers and stereochemistry including structural isomers, stereoisomers, diastereomers, and conformational isomers. By Jay.", 
                                    "id": "stereochemistry", 
                                    "title": "Stereochemistry"
                                }, 
                                {
                                    "description": "5B: Learn about covalent bonds and SP hybridization.  By Jay.", 
                                    "id": "covalent-bonds", 
                                    "title": "Covalent bonds"
                                }, 
                                {
                                    "description": "5C: Learn how to separate and purify chemical compounds using organic chemistry laboratory techniques, including extraction, distillation, chromatography, and gel electrophoresis.  By Angela Guerrero.", 
                                    "id": "separations-purifications", 
                                    "title": "Separations and purifications"
                                }, 
                                {
                                    "description": "5D: What are amino acids? How do they come together to form proteins? Learn about how amino acids synthesized, and then how they come together to form proteins. Discover how proteins are structured and what functions they perform on the cellular level.  By Tracy Kim Kovach.", 
                                    "id": "proteins", 
                                    "title": "Proteins"
                                }, 
                                {
                                    "description": "5D: Get a strong understanding of the nomenclature, properties, and reactions of alcohols and phenols, along with the criteria for determining aromaticity in benzene and aromatic heterocycles.  By Jay.", 
                                    "id": "alcohols-and-phenols", 
                                    "title": "Alcohols and phenols"
                                }, 
                                {
                                    "description": "5D: This tutorial will cover the important nomenclature, properties, and reactions of carboxylic acids", 
                                    "id": "carboxylic-acids", 
                                    "title": "Carboxylic acids"
                                }, 
                                {
                                    "description": "Come learn about enzymes and the basic principles behind enzyme mechanisms catalysis.  By Ross Firestone.", 
                                    "id": "enzymes", 
                                    "title": "Enzymes"
                                }
                            ], 
                            "description": "Foundational Concept 5: The principles that govern chemical interactions and reactions form the basis for a broader understanding of the molecular dynamics of living systems.", 
                            "id": "chemical-processes", 
                            "title": "Chemical processes"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "6A: Learn about how we perceive our various senses, including the theories, laws, and organizational principles that underly our ability to make sense of the world around us. By Ron Sahyouni", 
                                    "id": "sensory-perception", 
                                    "title": "Sensory perception"
                                }, 
                                {
                                    "description": "6A: Photons are hitting your eye as you read this!  Learn about our sense of sight, including the cells responsible for converting light into a neural impulse, the structure of the eye, and how we break down images to make sense of them.  By Ronald Sahyouni.", 
                                    "id": "sight", 
                                    "title": "Sight (vision)"
                                }, 
                                {
                                    "description": "6A: Learn about how we hear, including the structure of the outer, middle, and inner ear, as well as the basics of auditory processing & cochlear implants.", 
                                    "id": "sound-audition", 
                                    "title": "Sound (Audition)"
                                }, 
                                {
                                    "description": "6A: We perceive the environment through our bodily senses, including our sensation of pain, temperature, pressure, balance, and movement.  Discover how our body gathers this information and processes it so that we can make sense of the world.  By Ronald Sahyouni.", 
                                    "id": "somatosensation", 
                                    "title": "Somatosensation"
                                }, 
                                {
                                    "description": "6A: Learn about our senses of smell (olfaction) and taste (gustation), including the anatomy and underlying molecular basis behind these important senses.  By Ronald Sahyouni.", 
                                    "id": "taste (gustation) and smell (olfaction)", 
                                    "title": "Taste (gustation) and smell (olfaction)"
                                }, 
                                {
                                    "description": "6B: Explore cognitive development and intelligence, as well as how our minds solve problems, make decisions, and represent knowledge.", 
                                    "id": "cognition", 
                                    "title": "Cognition"
                                }, 
                                {
                                    "description": "6B: Have you ever tried to multi-task?  Explore the concept of selective and divided attention, as well as the role of language in cognition and development.  By Carole Yue.", 
                                    "id": "attention-language", 
                                    "title": "Attention and language"
                                }, 
                                {
                                    "description": "6B: Explore states of consciousness, circadian rhythms, sleep stages, and sleep disorders.  By Carole Yue.", 
                                    "id": "sleep-and-consciousness", 
                                    "title": "Sleep and consciousness"
                                }, 
                                {
                                    "description": "6B: Explore the structure of human memory; processes involved in normal encoding, retrieval, forgetting, and aging; and diseases affecting memory.", 
                                    "id": "memory", 
                                    "title": "Memory"
                                }, 
                                {
                                    "description": "6C: Learn about the physiological, behavioral, and cognitive components of emotion.  Appreciate how different areas of our brain play a role in emotion.  Understand the basic theories of emotion.", 
                                    "id": "emotion", 
                                    "title": "Emotion"
                                }, 
                                {
                                    "description": "6C: Stress is the natural process by which we evaluate and respond to the challenges and threats of our environment. Jump into this playlist to learn about stressors, stress reactions, the effects of stress, and strategies to manage this wild process.  By Ryan Patton.", 
                                    "id": "stress", 
                                    "title": "Stress"
                                }
                            ], 
                            "description": "Foundational Concept 6: Biological, psychological, and socio-cultural factors influence the ways that individuals perceive, think about, and react to the world.", 
                            "id": "processing-the-environment", 
                            "title": "Processing the environment"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "7A: Learn about the way our genes and experiences shape the way we respond to our environment.  By Ryan Patton.", 
                                    "id": "behavior-and-genetics", 
                                    "title": "Behavior and genetics"
                                }, 
                                {
                                    "description": "7A: An introduction to the structure and function of the nervous system.  By Matthew Jensen.", 
                                    "id": "biological-basis-of-behavior-ner", 
                                    "title": "Biological basis of behavior: Nervous system"
                                }, 
                                {
                                    "description": "7A: Review your understanding of the endocrine system, as we think about the context of glands and hormones in behavior.  By Ryan Patton.", 
                                    "id": "biological-basis-of-behavior-endocrine-system", 
                                    "title": "Biological basis of behavior: Endocrine system"
                                }, 
                                {
                                    "description": "7A: Curious about your personality?  Throughout history, famous psychologists and schools of thought have tried to figure out how to organize and categorize personalities.  Review these theories and see which one resonates the most with you!  By Shreena Desai.", 
                                    "id": "theories-personality", 
                                    "title": "Theories of personality"
                                }, 
                                {
                                    "description": "7A: What makes us do the things we do, or feel the way we feel in situations? Explore how the physiological and psycho-social theories, factors, and situations behind how motivation, attitudes, and behavior are inter-related.  By Shreena Desai.", 
                                    "id": "Physiological-and-sociocultural-concepts-of-motivation-and-attitudes", 
                                    "title": "Motivation and attitudes"
                                }, 
                                {
                                    "description": "7B: Dive into the fascinating and relevant world of social psychology! You may have noticed many of these concepts in your everyday life, but perhaps you did not know the proper terminology or the specific factors that motivate people to behave the way they do in groups. In this tutorial, you will learn some important aspects of social psychology.  By Jeffrey Walsh.", 
                                    "id": "social-psychology", 
                                    "title": "Social psychology"
                                }, 
                                {
                                    "description": "7B: Learn about how \"normal\" and \"deviant\" behavior is defined in today's society.  This includes a discussion of the range of normal and abnormal behavior, common theories used to understand basic deviance, and discussion of some types of deviance that occur in groups.  By Jeff Walsh.", 
                                    "id": "normative-and-non-normative-behavior", 
                                    "title": "Normative and non-normative behavior"
                                }, 
                                {
                                    "description": "7C: Learn about learning!  How does our environment influence our behavior?  What are the consequences of our behavior?  Understand the basics of classical and operant conditioning.  Appreciate how we learn through observation, and how it relates to the issue of violence in the media.  By Jeffrey Walsh.", 
                                    "id": "learning-slug", 
                                    "title": "Learning"
                                }
                            ], 
                            "description": "Foundational Concept 7: Biological, psychological, and socio-cultural factors influence behavior and behavior change.", 
                            "id": "behavior", 
                            "title": "Behavior"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "8A: Explore the ideas surrounding the concept of Self-Identity. Who are we? How do we develop our morals and patterns of learning? What influences our behaviors in social situations? Discover the importance of different phases of our life in our transformation into adulthood and old age.", 
                                    "id": "self-identity", 
                                    "title": "Self-identity"
                                }
                            ], 
                            "description": "Foundational Concept 8: Psychological, socio-cultural, and biological factors influence the way we think about ourselves and others.", 
                            "id": "individuals-and-society", 
                            "title": "Individuals and society"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "9A: What is a society? How do we humans all live together in such highly populated cities? How does a society change? Learn about some sociologic theories that have been proposed that try to address some of these important questions!  By Sydney Brown.", 
                                    "id": "social-structures", 
                                    "title": "Social structures"
                                }, 
                                {
                                    "description": "9B: There are many different ways of looking at a population. You can separate the population into different groups to view statistics. You can see how different populations interact or you can see how a population changes over time.", 
                                    "id": "demographics", 
                                    "title": "Demographics"
                                }
                            ], 
                            "description": "Foundational Concept 9: Cultural and social differences influence well-being.", 
                            "id": "society-and-culture", 
                            "title": "Society and culture"
                        }
                    ], 
                    "description": "This collection is being developed for the revised MCAT\u00ae exam that will first be administered in spring 2015. Videos will be added to the collection through fall 2014.  All content in this collection has been created under the direction of the Khan Academy and has been reviewed under the direction of the Association of American Medical Colleges (AAMC).  All materials are categorized according to the pre-health competencies tested by the MCAT\u00b2\u2070\u00b9\u2075 exam; however, the content in this collection is not intended to prescribe a program of study for the MCAT\u00b2\u2070\u00b9\u2075 exam. The content is also included in the Pre-health Collection within MedEdPORTAL\u2019s iCollaborative sponsored by the AAMC: www.mededportal.org/pre-health\n\n*MCAT\u00ae is a program of the AAMC and related trademarks owned by the Association include Medical College Admission Test, MCAT, and MCAT\u00b2\u2070\u00b9\u2075.  For more information about the MCAT exam visit : www.aamc.org/mcat2015", 
                    "id": "mcat", 
                    "title": "MCAT"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "rn-dysrhythmia-and-tachycardia", 
                                    "title": "Cardiac dysrhythmias and tachycardias"
                                }, 
                                {
                                    "description": "", 
                                    "id": "rn-non-cyanotic-heart-diseases", 
                                    "title": "Acyanotic heart diseases"
                                }, 
                                {
                                    "description": "", 
                                    "id": "rn-vasculitis", 
                                    "title": "Vasculitis"
                                }
                            ], 
                            "description": "With the heart pumping 24 hours a day, 7 days a week, it\u2019s absolutely vital to make sure things are flowing smoothly (pun intended!). Unfortunately, this isn\u2019t always the case, and different parts of the circulatory system can cause problems: your heart, your blood vessels, and even the fluid in your tissues and blood itself can be the issue. To further complicate things, the underlying reasons for circulatory system problems vary from your genes (nature) to your lifestyle habits (nurture). An understanding of how different diseases can affect your circulatory system is important to combat this growing problem in the world.", 
                            "id": "rn-cardiovascular-diseases", 
                            "title": "Cardiovascular system diseases"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "rn-intro-to-pulmonary-diseases", 
                                    "title": "Introduction to pulmonary diseases"
                                }, 
                                {
                                    "description": "", 
                                    "id": "rn-emphysema", 
                                    "title": "Emphysema (COPD)"
                                }, 
                                {
                                    "description": "", 
                                    "id": "rn-chronic-bronchitis", 
                                    "title": "Chronic bronchitis (COPD)"
                                }, 
                                {
                                    "description": "", 
                                    "id": "rn-lung-cancer", 
                                    "title": "Lung cancer"
                                }, 
                                {
                                    "description": "", 
                                    "id": "rn-pneumonia", 
                                    "title": "Pneumonia"
                                }, 
                                {
                                    "description": "", 
                                    "id": "rn-pleural-effusion", 
                                    "title": "Pleural effusion"
                                }
                            ], 
                            "description": "Our lungs are composed of a bronchial tree (think of an upside down tree with millions of leaves), blood vessels bringing blood in and out, and a protein-rich fluid that forms a matrix holding everything together! If any part of this well-balanced organ isn\u2019t working properly, a person can be left feeling short of breath. The lungs are also exposed to the outside environment, making them prone to infections. To counter infections, the lungs are lined with cells that have tiny protein bristles which wave back and forth and can literally sweep away dangerous bacteria. Learn more about diseases of the lungs and how modern medicine helps to keep them healthy!", 
                            "id": "rn-respiratory-system-diseases", 
                            "title": "Respiratory system diseases"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "rn-anemia", 
                                    "title": "Anemia"
                                }, 
                                {
                                    "description": "", 
                                    "id": "rn-leukemia", 
                                    "title": "Leukemia"
                                }
                            ], 
                            "description": "Blood is incredibly important in combating disease and the healing process after an injury. It acts as a highway for medicine, stops bleeding, fights infections, controls cells from multiplying too fast, and so much more. But things can go wrong with blood too! What if your blood couldn\u2019t clot and stop you from bleeding, or started to clot uncontrollably? What if your red blood cells or white blood cells suddenly disappeared? Blood contains many different types of tissues doing very different jobs, making diseases of the blood produce a variety of symptoms, including continuously feeling tired and bone pain. Learn about the different blood diseases, how they are diagnosed, and the cool ways health professionals treat these conditions.", 
                            "id": "hematologic-system-diseases", 
                            "title": "Hematologic system diseases"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "rn-the-endocrine-system", 
                                    "title": "Endocrine system"
                                }
                            ], 
                            "description": "Dive into the endocrine system! See how the body uses special organs (called glands) that secrete chemical messages (called hormones) in order to properly respond to it's changing environment.", 
                            "id": "rn-endocrine-system", 
                            "title": "Endocrine system"
                        }
                    ], 
                    "description": "This content has been developed to support nursing students preparing for the National Council Licensing Examination for Registered Nurses (NCLEX-RN). Videos and questions will be added to this collection throughout the summer and fall of 2014. All of this content has been created under the direction of Khan Academy and has been reviewed under the direction of the the American Association of Colleges of Nursing (AACN). This content is intended to be a supplemental resource for nursing graduates, not a program of study for the NCLEX-RN exam. The NCLEX-RN is administered by the National Council of State Boards of Nursing (NCSBN). For more information on the NCLEX-RN, visit: https://www.ncsbn.org/nclex.htm ", 
                    "id": "NCLEX-RN", 
                    "title": "NCLEX-RN"
                }, 
                {
                    "children": [
                        {
                            "description": "Sal works through the 249 problem solving questions in chapter 5 of the the 11th edition of the official GMAC GMAT Review (ISBN Number: 0-9765709-0-4 published in 2005)", 
                            "id": "problem-solving", 
                            "title": "Problem solving"
                        }, 
                        {
                            "description": "Sal works through the 155 data sufficiency questions in chapter 6 of the the 11th edition of the official GMAC GMAT Review (ISBN Number: 0-9765709-0-4 published in 2005)", 
                            "id": "data-sufficiency", 
                            "title": "Data sufficiency"
                        }
                    ], 
                    "description": "Sal works through problems in the 11th edition of the official GMAC GMAT Review (ISBN Number: 0-9765709-0-4 published in 2005).  You should take the practice tests on your own, grade them and then use these videos to understand the problems you didn't get or to review. Have fun!", 
                    "id": "gmat", 
                    "title": "GMAT"
                }, 
                {
                    "children": [
                        {
                            "description": "Sal working through the 53 problems from the practice test available at http://www.cde.ca.gov/ta/tg/hs/documents/mathpractest.pdf for the CAHSEE (California High School Exit Examination).  Clearly useful if you're looking to take that exam.  Probably still useful if you want to make sure you have a solid understanding of basic high school math.", 
                            "id": "cahsee", 
                            "title": "CAHSEE"
                        }
                    ], 
                    "description": "", 
                    "id": "cahsee-subject", 
                    "title": "CAHSEE"
                }, 
                {
                    "children": [
                        {
                            "description": "Questions from previous IIT JEEs", 
                            "id": "iit-jee", 
                            "title": "IIT JEE"
                        }
                    ], 
                    "description": "", 
                    "id": "iit-jee-subject", 
                    "title": "IIT JEE"
                }, 
                {
                    "children": [
                        {
                            "description": "", 
                            "id": "cultures-religions-ap-arthistory", 
                            "title": "Introduction to Cultures and Religions for the study of AP Art History"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Periods of time before the written record are often defined in terms of geological eras or major shifts in climate and environment. The periods of global prehistory, known as lithic or stone ages, are Paleolithic (\u201cold stone age\u201d), Mesolithic (\u201cmiddle stone age\u201d), and Neolithic (\u201cnew stone age\u201d). A glacial period produced European ice ages; Saharan agricultural grassland became desert; and tectonic shifts in southeast Asia created land bridges between the continent and the now-islands of the Pacific south of the equator. Human behavior and expression was influenced by the changing environments in which they lived.\n\nBy permission, \u00a9 2013 The College Board", 
                                    "id": "paleolithic-mesolithic-neolithic", 
                                    "title": "Paleolithic, Mesolithic and Neolithic"
                                }
                            ], 
                            "description": "Human expression existed across the globe before the written record. While prehistoric art of Europe has been the focus of many introductions to the history of art, very early art is found worldwide and shares certain features, particularly concern with the natural world and humans\u2019 place within it.\n\nBy permission, \u00a9 2013 The College Board", 
                            "id": "global-prehistory-ap", 
                            "title": "Global prehistory: 30,000-500 B.C.E."
                        }, 
                        {
                            "description": "The arts of South, East, and Southeast Asia represent some of the world\u2019s oldest, most diverse, and most sophisticated visual traditions.", 
                            "id": "south-east-southeast-asia", 
                            "title": "South, East, and Southeast Asia: 300 B.C.E.-1980 C.E."
                        }
                    ], 
                    "description": "Note: New materials are being added regularly. \n\nThe College Board announced that the art history exam and course will change in 2015. Khan Academy is working to include each of 250 works of art covered on the new test. The test also assesses a student\u2019s understanding of the methods used by art historians and familiarity with the cultural context in which a work of art was made and understood. Khan Academy\u2019s art history content is designed to teach these skills and to make the art engaging and accessible (and it\u2019s completely free!). Currently, more than 50% of the 250 monuments listed are included. We are working to cover the remaining content before the 2015/16 course begins. We will be adding quizzes at the end of each section to reinforce what you have learned and so that you can assess your understanding of the material. ", 
                    "id": "ap-art-history", 
                    "title": "AP Art History"
                }
            ], 
            "description": "", 
            "id": "test-prep", 
            "title": "Test prep"
        }, 
        {
            "children": [
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "cal-academy-welcome", 
                                    "title": "Welcome"
                                }
                            ], 
                            "description": "Take an expedition with us to investigate the amazing diversity of life on this planet. Learn what biodiversity is, why it is important, where it is found, how it comes into existence, how you study it, why it is threatened, and how it can be protected.", 
                            "id": "cas-welcome", 
                            "title": "Welcome to the world of biodiversity!"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "A wealth and variety of species, or species richness, promote strong ecological networks and functions, making ecosystems more resilient to major disturbances and collapse.", 
                                    "id": "biodiversity-and-ecosystem-funct", 
                                    "title": "Biodiversity and ecosystem function"
                                }, 
                                {
                                    "description": "Healthy ecosystems provide crucial direct, indirect, and aesthetic-ethical benefits to humans.", 
                                    "id": "biodiversity-and-ecosystem-servi", 
                                    "title": "Biodiversity and ecosystem services"
                                }
                            ], 
                            "description": "Discover why a high diversity of species sustains ecosystems, which in turn provide important services to humans.", 
                            "id": "why-is-biodiversity-important-ca", 
                            "title": "Why is biodiversity important?"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Areas that have a high diversity of unique and threatened species are known as biodiversity hotspots.", 
                                    "id": "biodiversity-hotspots-cas", 
                                    "title": "Biodiversity Hotspots"
                                }, 
                                {
                                    "description": "Life is abundant on Earth, but is distributed unevenly, with species richness and population sizes greater in some areas than others. The physical environment, other organisms, evolutionary factors, and human actions all influence where species live.", 
                                    "id": "distribution-patterns", 
                                    "title": "Biodiversity distribution patterns"
                                }
                            ], 
                            "description": "Explore how life is found almost everywhere on Earth, but is not distributed evenly. And learn why the clumped distributions of species are the result of a wide variety of both natural and human-driven factors.", 
                            "id": "where-biodiversity-is-found", 
                            "title": "Where is biodiversity found?"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "For centuries, expeditions to discover biodiversity have taken scientists to the far corners of the planet. Today\u2019s expeditions are multidisciplinary, incorporate new technologies and involve new ethics.\n", 
                                    "id": "biodiversity-fieldwork", 
                                    "title": "Biodiversity fieldwork"
                                }, 
                                {
                                    "description": "Collecting specimens in the field launches the lab work of analysis, documentation, and cataloging. Despite the ongoing work of scientists, only about 10% of Earth\u2019s biodiversity has been documented.", 
                                    "id": "biodiversity-analyses-and-uncertainties", 
                                    "title": "Biodiversity analyses and uncertainties"
                                }
                            ], 
                            "description": "Delve into the history of humanity\u2019s passion to document and display specimens from the natural world and learn how biodiversity expeditions are conducted today.", 
                            "id": "How-is-biodiversity-studied", 
                            "title": "How is biodiversity studied?"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Human population increase and activities threaten biodiversity in almost every corner of our planet. Local threats to species richness include land-use changes, pollution, resource exploitation, and invasive species.", 
                                    "id": "local-threats-to-biodiversity", 
                                    "title": "Local threats to biodiversity"
                                }, 
                                {
                                    "description": "Local impacts can have global consequences. Humans are causing accelerating changes in the atmosphere, on land, and in the oceans. Life in these changing environments is tough for many species.", 
                                    "id": "biodiversity-global", 
                                    "title": "Global threats to biodiversity"
                                }
                            ], 
                            "description": "Examine the local and global threats to biodiversity that are caused by human activities. Many of the negative impacts start as regional, but easily add up to affect the entire planet.", 
                            "id": "why-is-biodiversity-threatened", 
                            "title": "Why is biodiversity threatened?"
                        }
                    ], 
                    "description": "The California Academy of Sciences is a renowned scientific and educational institution dedicated \u0003to exploring and explaining the natural world and addressing the challenge of sustainability.", 
                    "id": "CAS-biodiversity", 
                    "title": "California Academy of Sciences"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "Have fun with colored light bulbs and experiment with different properties of light! Developed and demonstrated by Exploratorium Senior Scientist Paul Doherty.", 
                                    "id": "Colored-shadows", 
                                    "title": "Colored shadows"
                                }
                            ], 
                            "description": "Are all shadows black? Learn how to build fun, hands-on activities that explore light, color and human perception.", 
                            "id": "Light-and-color", 
                            "title": "Light and color"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Build a battery strong enough to power an LED using the change in your pocket! Developed and demonstrated by Julie Yu, director of the Exploratorium Teacher Institute.", 
                                    "id": "penny-battery", 
                                    "title": "Penny battery"
                                }
                            ], 
                            "description": "How can you power an LED with the change in your pocket? Build a cheap battery and learn how chemical energy gets converted into electricity.", 
                            "id": "exploratorium-chemistry", 
                            "title": "Chemistry"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Listen to a beam of light! Learn how to build a simple device in which the signal from a radio is transmitted on a beam of light traveling between a light-emitting diode (LED) and a solar cell. Developed by Exploratorium Teacher Institute staff Don Rathjen and demonstrated by Exploratorium Senior Scientist Paul Doherty.", 
                                    "id": "Light-to-sound", 
                                    "title": "Turn sound into light and back again"
                                }
                            ], 
                            "description": "Listen to a beam of light! Build a device that converts sound into light and explore the wonders of electromagnetism.", 
                            "id": "Expl-sound", 
                            "title": "Electromagnetism"
                        }
                    ], 
                    "description": "The Exploratorium is a 21st-century learning laboratory and museum based in San Francisco. For more than forty years, we\u2019ve built creative, thought-provoking exhibits, tools, programs, and experiences that ignite curiosity, encourage exploration, and lead to profound learning. The science \"snacks\" on this website are fun, hands-on activities developed and thoroughly tested by the Exploratorium Teacher Institute. Dive in and discover what we're all about!", 
                    "id": "Exploratorium", 
                    "title": "Exploratorium"
                }, 
                {
                    "children": [
                        {
                            "description": "Hinduism has no historical founder, and no central authority.  It includes enormously diverse beliefs and practices, which vary over time and among individuals, communities, and regional areas.  Its authority\u2014its beliefs and practices\u2014rests on a large body of sacred texts that may date back more than 3,000 years.   ", 
                            "id": "aam-hinduism", 
                            "title": "Hinduism"
                        }, 
                        {
                            "description": "Many products and technologies that were first developed in China\u2014silk, porcelain, gunpowder, tea, paper, and woodblock printing\u2014were much sought after by cultures far beyond its borders. In exchange the Chinese sought exotic goods, horses, and jade, as well as access to the sources of Buddhism.", 
                            "id": "aam-China", 
                            "title": "China"
                        }, 
                        {
                            "description": "Few people are aware that the name Korea is derived from the name of the Goryeo (previously transliterated as Koryo) dynasty. It was during this period (918\u20131392) that Korea became known to the world outside East Asia. ", 
                            "id": "aam-Korea", 
                            "title": "Korea"
                        }, 
                        {
                            "description": "Part of a long archipelago off the eastern rim of the Asian continent, the island country of Japan has four main islands: Hokkaido, Honshu, Shikoku, and Kyushu. Numerous smaller islands lie on either end to form a sweeping arc formation that extends northeast to southwest. Another distinctive feature of the Japanese landscape is its volcanic, mountainous terrain. More than two thirds of the land is adorned with low to steep mountains traversed by swift-flowing rivers. These dramatic geographic features have shaped Japan's political history and artistic culture. ", 
                            "id": "aam-Japan", 
                            "title": "Japan"
                        }, 
                        {
                            "description": "Art conservation work includes treatment and preventive care, scholarly research on materials and techniques, and development of new conservation methods to address the changing needs of a growing museum. The Conservation Center at the Asian Art Museum shares the mandate of the museum to create a deeper level of understanding of Asian cultures by our visitors. Through cooperative exchanges, joint projects, and public outreach, art conservation can provide a unique window into shared traditions of art preservation, restoration and fabrication. ", 
                            "id": "aam-conservation", 
                            "title": "Art Conservation"
                        }
                    ], 
                    "description": "The Asian Art Museum is one of the largest museums in the Western world devoted exclusively to Asian art and culture. Home to more than 18,000 works of art from over 40 Asian countries, we strive to be a catalyst for discovery, dialogue, and inspiration. With Asia as our lens and art as our cornerstone, we spark connections across cultures and through time, igniting curiosity, conversation, and creativity.", 
                    "id": "asian-art-museum", 
                    "title": "Asian Art Museum"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "Get an overview of blended learning along with the definition of blended learning and an introduction to several different models of blended learning.", 
                                    "id": "sscc-overview-blended-learning", 
                                    "title": "An overview of blended learning"
                                }, 
                                {
                                    "description": "", 
                                    "id": "sscc-blended-learning-models", 
                                    "title": "Four different blended learning models"
                                }
                            ], 
                            "description": "An overview, definition and introduction to several different models of blended learning", 
                            "id": "sscc-intro-blended-learning", 
                            "title": "Introduction to blended learning"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "sscc-student-experience-overview", 
                                    "title": "Student experience overview"
                                }, 
                                {
                                    "description": "", 
                                    "id": "sscc-learning-environments", 
                                    "title": "The learning environment in a station rotation, lab rotation and flex model"
                                }, 
                                {
                                    "description": "", 
                                    "id": "sscc-preparing-students", 
                                    "title": "Preparing students for success"
                                }
                            ], 
                            "description": "Learn how educators are redesigning schools and the use of time and teachers to create their most ideal blended learning environment.  Explore how to help students transition smoothly from traditional education to blended learning", 
                            "id": "ccss-ideal-student-experience", 
                            "title": "Creating the ideal student experience in a blended learning classroom"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "sscc-teacher-experience", 
                                    "title": "An overview of the teacher experience"
                                }, 
                                {
                                    "description": "", 
                                    "id": "sscc-blended-case-studies", 
                                    "title": "Case studies: teaching in a blended learning environment"
                                }, 
                                {
                                    "description": "", 
                                    "id": "sscc-blended-learning-motives", 
                                    "title": "The moves of a blended learning teacher"
                                }
                            ], 
                            "description": "Discover how the role of the teacher is changing in blended-learning environments.  What parts of the job stay the same and what is different?  How does an organization support teachers in making the transition to blended learning?", 
                            "id": "sscc-teaching-blended-learning", 
                            "title": "Teaching in a blended learning environment \u2013 rethinking the role of the teacher"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "sscc-school-redesign", 
                                    "title": "School redesign overview"
                                }, 
                                {
                                    "description": "", 
                                    "id": "sscc-challenging-assumptions", 
                                    "title": "Challenging existing assumptions"
                                }, 
                                {
                                    "description": "", 
                                    "id": "sscc-leading-change", 
                                    "title": "Leading change in blended learning"
                                }
                            ], 
                            "description": "How can we challenge our assumptions about the ways that schools have always been organized and run?  How do leaders manage the change as their organizations transition from traditional models to blended learning?", 
                            "id": "sscc-design-blended-learning", 
                            "title": "Redesigning a school toward blended learning"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "sscc-decisions-overview", 
                                    "title": "Hardware, software and facilities decisions overview"
                                }, 
                                {
                                    "description": "", 
                                    "id": "sscc-blended-software", 
                                    "title": "Blended learning software"
                                }, 
                                {
                                    "description": "", 
                                    "id": "sscc-blended-hardware", 
                                    "title": "Blended learning hardware and infrastructure"
                                }, 
                                {
                                    "description": "", 
                                    "id": "sscc-facilities-furniture", 
                                    "title": "Blended learning facilities and furniture"
                                }
                            ], 
                            "description": "Explore the choices you have to make around your software, hardware, and facilities and how to make sure they support your educational model", 
                            "id": "sscc-blended-learning-decisions", 
                            "title": "Making aligned hardware, software, and space decisions in a blended learning environment"
                        }
                    ], 
                    "description": "Silicon Schools Fund and the Clayton Christensen Institute have teamed up to provide insight and guidance on delivering high-quality blended learning.  Learn more about how to personalize K-12 education for all students by combining the best of traditional schools with the transformative power of online learning.", 
                    "id": "ssf-cci", 
                    "title": "Silicon Schools Fund and Clayton Christensen Institute"
                }, 
                {
                    "children": [
                        {
                            "description": "LeBron James asks questions about math and science, and we answer!", 
                            "id": "lebron-asks", 
                            "title": "LeBron asks"
                        }
                    ], 
                    "description": "LeBron James asks questions about math and science, and we answer!", 
                    "id": "lebron-asks-subject", 
                    "title": "LeBron asks"
                }, 
                {
                    "children": [
                        {
                            "description": "This tutorial introduces the structure of the U.S. health care system, how money flows within it, and an overview of different types of public and private insurance. These videos and questions provide a clear explanation of what is and is not working within the health care system to help frame the health care reform discussion and inform clinicians and the public how to improve quality while decreasing health care spending.  Narrated by Dr. Darshak Sanghavi, a pediatric cardiologist and fellow at Brookings Institution.", 
                            "id": "introduction to healthcare", 
                            "title": "Introduction to health care in the U.S."
                        }
                    ], 
                    "description": "Designed for clinicians as well as the general public, these engaging tutorials provide an overview of the U.S. health care system and payment and delivery reform efforts at the federal, state, and local levels. Created by the Merkin Initiative at The Brookings Institution and presented by Khan Academy, the content covers an introduction to health care costs, Medicare, Medicaid, prescription drug coverage, and more.", 
                    "id": "brookings-institution", 
                    "title": "The Brookings Institution"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "These videos introduce the American Revolution, providing the context necessary to take your learning to a deeper level. ", 
                                    "id": "American-Revolution", 
                                    "title": "The American Revolution"
                                }
                            ], 
                            "description": "The American struggle for independence from Great Britain did not come easily.  The debates among the founders of America were rigorous and there were ideological divides where compromise allowed for a unified revolution.  The battles of the American Revolution cost many men their lives without any guarantee that this experiment in democracy would succeed.", 
                            "id": "Intro-American-Revolution", 
                            "title": "An introduction to the American Revolution"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "aspen-declaration-independence", 
                                    "title": "The Declaration of Independence"
                                }, 
                                {
                                    "description": "", 
                                    "id": "articles-of-confederation", 
                                    "title": "The Articles of Confederation"
                                }, 
                                {
                                    "description": "", 
                                    "id": "aspen-constitution", 
                                    "title": "The Constitution of the United States"
                                }
                            ], 
                            "description": "There wasn\u2019t any email or SMS in the 1700s when the founders of America sent letters and drafted the documents that became the blueprint for American democracy. The documents of the founding of America tell the story of issues being grappled with and personalities discussing moral and ideological differences.   ", 
                            "id": "aspen-founding-docs", 
                            "title": "The founding documents of the United States"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "George Washington was the first President of the United States but before that he was the General of the Continental Army.  Hear Pulitzer Prize winning historian Joe Ellis discuss George Washington with Aspen Institute's Walter Isaacson. ", 
                                    "id": "aspen-george-washington", 
                                    "title": "George Washington"
                                }, 
                                {
                                    "description": "Franklin was a great inventor and statesman and had an invaluable role in the founding of America.", 
                                    "id": "aspen-benjamin-franklin", 
                                    "title": "Benjamin Franklin"
                                }, 
                                {
                                    "description": "Madison is known as the \"father of the Constition.\"", 
                                    "id": "James-Madison", 
                                    "title": "James Madison"
                                }, 
                                {
                                    "description": "Hamilton was a strong believer is a central federal government, a debate that continues to this day. ", 
                                    "id": "Alexander-Hamilton", 
                                    "title": "Alexander Hamilton"
                                }
                            ], 
                            "description": "From the variety of personalities of the founding fathers to the issue of slavery and representative democracy, the early days of the United States of America were filled with debate and compromise and the building blocks of a democracy that survives today.", 
                            "id": "founding-fathers", 
                            "title": "The founding fathers of the United States of America"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "", 
                                    "id": "women-colonial-America", 
                                    "title": "Women in early America"
                                }, 
                                {
                                    "description": "", 
                                    "id": "martha-washington", 
                                    "title": "An introduction to the founding mothers"
                                }, 
                                {
                                    "description": "", 
                                    "id": "women-expansion-america", 
                                    "title": "Women and the expansion of America"
                                }
                            ], 
                            "description": "The term \"founding fathers\" is synonymous with the American Revolution and the founding of the United States of America, however, there were women who played an important role in the founding as well.  Journalist Cokie Roberts explores the role of women in America's founding and discusses with Aspen Institute President and CEO Walter Isaacson America's \"Founding Mothers.\"", 
                            "id": "founding-mothers", 
                            "title": "The founding mothers of the United States of America"
                        }
                    ], 
                    "description": "The Aspen Institute is an educational and policy studies organization. Its mission is to foster leadership based on enduring values and to provide a nonpartisan venue for dealing with critical issues. The Aspen Institute and Khan Academy partnership is made possible with the support of the Kimsey Foundation.", 
                    "id": "aspeninstitute", 
                    "title": "The Aspen Institute"
                }, 
                {
                    "children": [
                        {
                            "children": [
                                {
                                    "description": "This video is a short introduction to the resources developed by NASA and Khan Academy.", 
                                    "id": "nasa-mission-control", 
                                    "title": "Welcome"
                                }
                            ], 
                            "description": "Welcome to NASA Mission control, an introduction to the learning and exploration adventures offered in cooperation between NASA and Khan Academy!", 
                            "id": "nasa-welcome", 
                            "title": "Welcome to NASA Mission Control"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Astronomy begins when we look up and start asking questions. Where are we? How big is the earth? This lesson is for all ages, start here!", 
                                    "id": "spacemath1", 
                                    "title": "Modeling the solar system"
                                }, 
                                {
                                    "description": "How can we apply geometry and trigonometry in order to measure the size of the earth, moon and sun?", 
                                    "id": "measure_the_solarsystem", 
                                    "title": "Measuring the solar system"
                                }, 
                                {
                                    "description": "How do planets move? An introduction to orbital mechanics and the work of Johannes Kepler.", 
                                    "id": "orbital-mechanics", 
                                    "title": "Orbital mechanics 1"
                                }, 
                                {
                                    "description": "There is much more to light than meets the eye. Introduction to the electromagnetic spectrum and the science of spectroscopy.", 
                                    "id": "spectroscopy", 
                                    "title": "Spectroscopy"
                                }
                            ], 
                            "description": "How have we applied science and mathematics to understand our solar system?", 
                            "id": "measuringuniverse", 
                            "title": "Measuring the Universe"
                        }, 
                        {
                            "children": [
                                {
                                    "description": "Where is Mars? How does it move? How far away is it? What are the conditions on the surface? This tutorial covers our initial observations of the Red Planet", 
                                    "id": "exploring_mars_ancient", 
                                    "title": "Mars: Ancient observations"
                                }, 
                                {
                                    "description": "What are the conditions on the surface of Mars? Does it have life? Does it have water? Was the ancient environment habitable on Mars? This tutorial covers 20th century discoveries.", 
                                    "id": "mars-modern-exploration", 
                                    "title": "Mars: Modern exploration"
                                }, 
                                {
                                    "description": "Why are we going to Mars today, where are we looking, what are we hoping to find?", 
                                    "id": "mars_science_lab", 
                                    "title": "Curiosity rover: mission briefing"
                                }, 
                                {
                                    "description": "What did the curiosity rover find? Follow the mission timeline & findings here.", 
                                    "id": "curiosity-discoveries", 
                                    "title": "Curiosity rover: discoveries"
                                }
                            ], 
                            "description": "Centuries of observations ignited curiosity about other bodies in our solar system. Eventually, we reached out and touched them...what did we find?", 
                            "id": "searchingforlife", 
                            "title": "Exploring the Universe"
                        }
                    ], 
                    "description": "NASA's vision is to reach for new heights and reveal the unknown so that what we do and learn will benefit all humankind.\n\nThis section contains a series of tutorials on astronomy and space exploration developed in collaboration with NASA", 
                    "id": "nasa", 
                    "title": "NASA"
                }
            ], 
            "description": "", 
            "id": "partner-content", 
            "title": "Partner content"
        }
    ], 
    "description": "", 
    "id": "root", 
    "title": "Khan Academy"
}
