Lemmings are small, thickset vole-like animals that live in the Arctic tundra. They live in a harsh environment, are super-cute, kinda mean, and totally misunderstood.

You might be benefiting from the weird units you've never heard every time you put on your shoes or read about dark matter.

Jessi and Squeaks love to race each other! They can both run pretty fast, but there's one animal they'd never be able to beat: the cheetah! Join us to learn all about this super speedy cat!

Claws and teeth are one way to catch a meal, but here are six animals that have evolved some pretty unique hunting techniques. Chapters FROGFISH 0:51 BOLAS SPIDERS 2:16 3 HUMPBACK WHALES 4:22 PISTOL SHRIMP 5:19 8:14 HUMANS 8:39

* Viewer discretion advised. This video includes discussion of mature topics and may be inappropriate for some audiences. In an engaging and personal talk -- with cameo appearances from his grandmother and Rosa Parks -- human rights...

Do you need some help? It's OK to ask, says YeYoon Kim, a former kindergarten teacher who learned from her students how powerful and courageous it can be to reach out for support. Sharing the story of one of the most difficult periods in...

When you’re sick you just want to be left alone. Sometimes that’s because you physically can’t move, but other times, it might have more to do with the way your immune system is connected to your brain.

When the weather starts to get cool, a lot of people start to get sick. So what’s making people sick and how can you avoid falling ill? Join Jessi and Squeaks to find out!

Hank talks about everyone's favorite squeaky-voice gas and why it's important for more than party balloons.

Fresh water is essential for life -- and there's not nearly enough of it for the world right now. Why is that, and what could we do? Christiana Z. Peppard lays out the big questions of our global water problem. And no, shorter showers...

When trying to come up with a new idea, we all have times when we get stuck. But according to research by behavioral and learning scientist Marily Oppezzo, getting up and going for a walk might be all it takes to get your creative juices...

World-class sprinters just keep getting faster, with some running over 40 kilometers per hour! That kind of makes you wonder… how much faster can humans get?

How DO you make a digital clock?

Have you ever wondered why your shadow is longer sometimes and shorter others? It turns out it all has to do with that marvelous big ball of light in the sky; The Sun! This first series is based on 5th grade science. We're super excited...

So maybe we can't outrun cheetahs or antelope, but humans are uniquely adapted for long distance running. What does science have to say about marathon running? To find out, (and because I was feeling a little crazy) I decided to run one!...

There's so much water in the ocean, but why can't we drink it? Jessi and Squeaks talk about the difference between ocean water and the water you drink at home.

We've heard that bees are disappearing. But what is making bee colonies so vulnerable? Photographer Anand Varma raised bees in his backyard — in front of a camera — to get an up close view. This project, for National Geographic, gives a...

Get to know your body’s most important muscle -- your heart -- and learn how to take your own pulse!

New ReviewUse the tiny loop on your shirt to hang it when you’re out of hangers, and speed up phone charging by switching to airplane mode. Plus, discover how bubbles help keep your bathwater warm longer and how storing peanut butter upside down...

New ReviewImprove your English with our original drama series. In this episode, you’ll hear real English conversations, learn everyday expressions, and practice listening comprehension in a fun, story-driven format. For learners at the...

Develop ethical decision-making skills in business technology and communication. Learn responsibilities, proper use, and boundaries in Part 4 of this training.

In this video, observe a practical demo of OSPF basic configuration.

In this video, watch how administrative distance is used to prioritize routes in a routing table.

In this video, watch a practical demonstration of the boot-up process on a Cisco device.