Slavery has occurred in many forms throughout the world, but the Atlantic slave trade -- which forcibly brought more than 10 million Africans to the Americas -- stands out for both its global scale and its lasting legacy. Anthony Hazard...

Aliens have invaded ancient history: they've cropped up in humanity's past through popular television and movies, displacing facts with absurd yet commonplace beliefs like "aliens built the pyramids." Archaeologist Sarah Kurnick...

Hank introduces us to the "simplest" of the animals, complexity-wise: beginning with sponges (whose very inclusion in the list as "animals" has been called into question because they are so simple) and finishing with the most complex...

In this video Paul Andersen explains how fossil fuels are formed when organic material is heating and squeezed in an anaerobic environment. Formation, extraction, advantages, and disadvantages are discussed for coal, petroleum and...

Over the years, lots of explanations have been proposed as the origin of Stonehenge, including lost technologies, outright magic, and — of course — aliens. What do we actually know about this prehistoric mystery?

Even an empty lunch sack is useful to science. You can examine it and come up with some traits. In this episode, Sabrina chats about things like malleability, hardness, conductivity, and magnetism. And all with lunch! This first series...

Wondering how you can catch the perfect wave? Dive into the fascinating and complex physics of surfing. -- Whether or not you realize it, surfers are masters of complicated physics. The science of surfing begins as soon as a board...

In which John Green, Hank Green, and Emily Graslie teach you about our Sun, and the formation of the planets. We're going to focus on the formation and development of the Earth, because that's where people live. You'll learn about the...

Twenty four hundred years ago, Plato, one of history's most famous thinkers, said life is like being chained up in a cave forced to watch shadows flitting across a stone wall. Beyond sounding quite morbid, what exactly did he mean? Alex...

Few individuals have influenced the world and many of today's thinkers like Plato. He created the first Western university and was teacher to Ancient Greece's greatest minds, including Aristotle. But even he wasn't perfect. Along with...

Did you know that of all of the rocks in the world, there are only 3 main kinds? What are they? And how can you tell them apart? Jessi and Squeaks show you how you can become a rock detective!

Spangler has the cure!

It's a math teacher's dream!

We've learned quite a lot about third declension nouns but there are some special members of this group that require some additional explanation. Let's check them out!

Does Microwaving Make Food Harmful?

Howcast - Admit it, daredevil—you've been waiting to fly since the day you were born. Find a great instructor, throw on that jumpsuit, and get ready for freefall!

Howcast - Learn what you need to know about garlic supplements from registered dietician Glen Tobias in this Howcast video.

Howcast - Learn all about acai and its anti-oxidant properties from registered dietician Glen Tobias in this Howcast video.

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Howcast - Learn about the spice fenugreek and how it's used in Indian recipes from cookbook author Maya Kaimal in this Howcast food video.

Howcast - Learn how to do advanced block karate moves from karate instructor Richard Amos in this Howcast video.

Howcast - Learn what karate classes are like from karate instructor Richard Amos in this Howcast video.

Howcast - Learn about magician Jason Suran, one of Howcast's experts at coin tricks and card tricks, in this video.

Howcast - Learn how to talk to your doctor about medical marijuana in this Howcast video.