Confused about how chromosome numbers change before and after mitosis and meiosis? This Amoeba Sisters UPDATED video breaks down chromosome vs chromatid and shows how to count chromosomes and how they change in cell division, all...

Join the Amoeba Sisters as they introduce the cardiac conduction system! This video mentions conductive cardiac cells (focusing on pacemaker cells) in the SA and AV nodes and discusses general steps of spontaneous depolarization. It also...

Join Pinky and Petunia in a cell types review game! This review game focuses on comparing cell characteristics of animals, plants, fungi, "protists," archaea, and bacteria. Clues may include prokaryote/eukaryote, autotroph/heterotroph,...

There are about 7,000 languages spoken around the world -- and they all have different sounds, vocabularies and structures. But do they shape the way we think? Cognitive scientist Lera Boroditsky shares examples of language -- from an...

In which John Green teaches you about World War II, aka The Great Patriotic War, aka The Big One. So how did this war happen? And what does it mean? We've all learned the facts about World War II many times over, thanks to repeated...

In which John Green teaches you about World War II, and some of the causes behind the war. In a lot of ways, WWII was about resources, and especially about food. The expansionist aggression of both Germany and Japan were in a lot of ways...

In which John Green teaches you about nation building and nationalism in Latin America. Sometimes, the nations of Latin America get compared to the nations of Europe, and are found wanting. This is kind of a silly comparison. The rise of...

In which John Green investigates war, and what exactly it may or may not be good for. Was war a result of human beings organizing into larger and more complex agricultural social orders, or did war maybe create agriculture and...

In which John Green teaches you about Vikings! That's right, one of our most requested subjects, the Vikings, right here on Crash Course. So what's the deal with Vikings? Well, the stuff you've heard about them may not be true. The...

In which John Green teaches you about railroads, and some of the ways they changed the world, and how they were a sort of microcosm for the Industrial Revolution as a whole. Prior to the invention of steam powered railroads, pretty much...

In which John Green teaches you about the Mughal Empire, which ruled large swaths of the Indian Sub-Continent from 1526 to (technically) 1857. While John teaches you about this long-lived Muslim empire, he'll also look at the idea of...

In which John Green teaches you about the Bronze Age civilization in what we today call the middle east, and how the vast, interconnected civilization that encompassed Egypt, The Levant, and Mesopotamia came to an end. What's that you...

In which John Green returns to teaching World History! This week, we'll be talking about the idea of civilization, some of the traditional hallmarks of so-called civilization, and why some people would choose to live outside the...

In which John Green teaches you about population. So, how many people can reasonably live on the Earth? Thomas Malthus got it totally wrong in the 19th century, but for some reason, he keeps coming up when we talk about population. In...

In which John Green teaches you about nonviolence and peace movements in the 20th century. What is nonviolence? What is a peace movement? Well. traditionally, humans often resort to violence when they come into conflict. In the 20th...

In which John Green teaches about filthy, filthy lucre. Money. And Debt. So, what is money? And what is it for? And why do we use money? And why does it all disappear so quickly after payday? John will look into 75% of these questions,...

In which John presents Mesopotamia, and the early civilizations that arose around the Fertile Crescent. Topics covered include the birth of territorial kingdoms, empires, Neo-Assyrian torture tactics, sacred marriages, ancient labor...

In which John Green teaches you about the Protestant Reformation. Prior to the Protestant Reformation, pretty much everyone in Europe was a Roman Catholic. Not to get all great man, but Martin Luther changed all that. Martin Luther...

In which Stan Muller subs for John Green and teaches you about energy and humanity. Today we discuss the ideas put forth by Alfred Crosby in his book, Children of the Sun. Historically, almost all of the energy that humans use has been...

In which John Green teaches you a little bit about drought, which is a natural weather phenomenon, and famine, which is almost always the result of human activity. Throughout human history, when food shortages strike humanity, there was...

In which John Green teaches you about the end of World History, and the end of the world as we know it, kind of. For the last hundred years or so, it seemed that one important ingredient for running an economically successful country was...

In which John Green teaches you about the Democratic Republic of the Congo, which used to be Zaire, which used to be The Belgian Congo, which used to be the Congo Free State, which used to be the region surrounding the Congo River Basin...

In which John Green teaches you about Imperialism, but not from the perspective of the colonizers. This week John looks at some Asian perspectives on Imperialism, specifically writers from countries that were colonized by European...

In which John Green talks about the methods of writing history by looking at some of the ways that history has been written about the rise of the West. But first he has to tell you what the West is. And then he has to explain the Rise of...