There’s more to DNA than just the double helix we know and love: under some conditions this familiar molecule can take on unfamiliar forms, each of which can have a different impact on our health.

Getting our hands on a few moon rocks radically changed our understanding of the solar system!

Today, we’re going to visit Siberia and take a closer look at how temperatures there (and around the globe) impact the way cultures, communities, and landscapes form. Air temperature plays a much bigger role than just helping us decide...

You might have wondered if putting on or taking off glasses is enough to completely transform Clark Kent/Superman’s appearance. Researchers have looked into this, and the result is pretty surprising.

The Brodie helmet, widely used during the first World War, had some serious design flaws, . But thanks to those flaws we now have a staggeringly accurate map of the brain.

A very clever proof of Euler's characteristic formula using spanning trees.

Mirror neurons are a very cool part of our brains but some people are taking it way further by making claims that they are responsible for telepathy and ESP. It goes without saying that this isn’t true, but what exactly do mirror neurons...

In 19th century Europe, with nation building well under way, thoughts turned outward, toward empire. This week, we're looking at how Europeans expanded into Africa, Asia, and Oceania during the 1800s. You'll learn about China and the...

In the African grasslands, a gazelle suffering from tuberculosis takes its last breath. The animal's corpse threatens to infect the water, but for the vulture, this isn't a problem: it's a feast. With a stomach of steel that can digest...

An adult human can distinguish up to 10,000 odors. You use your nose to figure out what to eat, what to buy and even when it's time to take a shower. But how do the molecules in the air get translated into smells in your brain? Rose...

Water is one of the most abundant and important substances on Earth, so you think we'd know everything there is to know about it. But it turns out water is way weirder, and it often behaves in ways that leave scientists with more...

Our diets are more global than we realize, because our common food crops and animals were domesticated far away in diverse locations.

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We’ve all heard the phrase “opposites attract.” It may or may not be true for people, but it’s definitely true in organic chemistry. In this episode of Crash Course Organic Chemistry, we’re learning about electronegativity, polarity,...

Bones might seem rock-solid, but they’re actually quite porous inside. Most of the large bones of your skeleton have a hollow core filled with soft bone marrow. Marrow's most essential elements are blood stem cells and for patients with...

Researchers have unlocked the final gaps in the human genome, and what they tell us could mean big waves for the future of medicine.

Despite water covering 71% of the planet’s surface, more than half the world’s population endures extreme water scarcity for at least one month a year. Current estimates predict that by 2040, up to 20 more countries could be...

in 19th-century England, scientists were figuring out that certain parts of our brains were connected with certain parts of our bodies- but they came up with some terrible and misleading ideas that spread without rigorous scientific...

In our final episode of Crash Course Geography we're going to take a look towards the future, and to do that we'll need to revisit our fundamental geography tools: space, place, and human-environment interactions! We'll talk about the...

It's time to have a look at the future of human life and how technology could possibly extend longevity. But, within that tech, are questions of ethics that are not always at the top of mind when the tech is being developed. In this...

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...

There are aspects of computer code that look like language and some that seem more like algebra, and since we may be headed for a future where many people will need to learn to code, researchers are interested in figuring out how exactly...

It seems like stimulants and hyperactivity shouldn't mix, so why are they so often prescribed to treat ADHD?

While the weather in Iceland is often cold, wet, and windy, a nearly endless supply of heat bubbles away below the surface. In fact, almost every building in the country is heated by geothermal energy in a process with virtually no...

Why is there a hexagonal structure in honeycombs? Why not squares? Or asymmetrical blobby shapes? In 36 B.C., the Roman scholar Marcus Terentius Varro wrote about two of the leading theories of the day. First: bees have six legs, so they...