In 2010, 30 billion dollars worth of fruits and vegetables were wasted by American retailers and shoppers, in part because of cosmetic problems and perceived spoilage. But what are these spots, anyway, and are they okay to eat? Elizabeth...

We've talked about food chains and how energy moves through an ecosystem, but let's take a step back and see how everything starts... and ends. Decomposers! This first series is based on 5th grade science. We're super excited and hope...

Are humans really Earth's most dominant species? Let's put all of the planet's living things on a scale and see what has amassed the most mass. This week we break down the concept of "biomass" to judge Earth's living things from top to...

420 million years ago, a giant feasted on the dead, growing slowly into the largest living thing on land. It belonged to an unlikely group of pioneers that ultimately made life on land possible -- the fungi.

Paul Andersen shows you how to graph data by hand. He explains the required elements of a scatter plot with a best fit line. He shows you how to properly scale and label the axes.

So... do plants need dirt? The truth might shock you. In this episode of Crash Course kids, Sabrina talks about how plants get energy and how that energy is transported around them. Also, she talks about dirt.

In this episode of Crash Course Kids, Sabrina gives us a real world example of how the Hydrosphere and Geosphere affect each other in the form of Weathering and Erosion. Think of Weathering as the force that makes a mess and Erosion as...

Some trees lose their leaves in the fall, but some keep their green leaves all year round. Join Jessi and Squeaks to learn about evergreens: where they grow, and how they survive in harsh conditions!

Jessi and Squeaks just learned about terrariums, and now they want to make one for themselves! Join them to learn all about these tiny gardens in a bottle and how you can make one of your own!

In this brief talk from TED U 2009, Jonathan Drori encourages us to save biodiversity -- one seed at a time. Reminding us that plants support human life, he shares the vision of the Millennium Seed Bank, which has stored over 3 billion...

Paul Andersen describes how plants and animals defend themselves against pathogens. He begins by discussing the hypersensitive response in plants as a nonspecific form of immune response. He then discusses both the humoral and...

Meet some real-life robots, and find out what robots really are, and what they do for us every day!

For the last 50 years we've wondered whether plants can think... Haven't we?

Last time we put a Polar Bear in the desert and we still feel bad about that, but there's a lot more going on in ecosystems than just temperature. In fact, there are so many elements in ecosystems, that if just one leaves or gets out of...

Jessi and Squeaks show you how a tiny seed, like the kind you eat in your trail mix! Grows into a big plant!

Paul Andersen explains how nutrients and water are transported in plants. He begins with a brief discussion of what nutrients are required by plants and where they get them. He shows you dermal, vascular and ground tissue in monocot and...

Want to learn how plants move water around inside them? Or do you just want to turn a stalk of celery purple? Then try our amazing color-changing celery experiment, in class or at home!

Jessi and Squeaks want to learn more about the inside of a pumpkin. How? By dissecting it!

With stunning photos and stories, National Geographic Explorer Wade Davis celebrates the extraordinary diversity of the world's indigenous cultures, which are disappearing from the planet at an alarming rate.

Hank veers away from human anatomy to teach us about the (mostly) single-celled organisms that make up two of the three taxonomic domains of life, and one of the four kingdoms: Archaea, Bacteria, and Protists. They are by far the most...

Forests don't have to be far-flung nature reserves, isolated from human life. Instead, we can grow them right where we are -- even in cities. eco-entrepreneur and TED Fellow Shubhendu Sharma grows ultra-dense, biodiverse mini-forests of...

Hank talks about the last major way humans are impacting the environment in this penultimate episode of Crash Course Ecology. Pollution takes many forms - from the simplest piece of litter to the more complex endocrine distruptors - and...

What happens to a single ecosystem when the amount of freshwater available in it changes? Not really much good. In this episode of Crash Course Kids, Sabrina talks about ecosystems and how one small change can lead to a cascade effect in...

Mr. Andersen gives a brief description of the scientific method.