Grades 3-5

Reefs in Crisis

Online Resource, Article

Reefs in Crisis

Humans have harmlessly harvested coral reefs for thousands—or even hundreds of thousands—of years. So why has our behavior in recent years suddenly put reefs at risk?

Studying Tree Rings to Learn About Global Climate

Online Resource, Article

Studying Tree Rings to Learn About Global Climate

By taking biopsy-like samples from centuries-old Siberian pines, scientists have reconstructed a 300-year record of temperature changes for the Arctic and the Northern Hemisphere.

Saving Species

Saving Species

Take a world-wide tour of biodiversity. You'll meet mollusks in the reefs off the Bahamas, the aye-aye in the tropical forests of Madagascar, and the clever mimic-ant spider that lives in Australia.

Work the System!

Work the System!

Did you know that forests with leaves above the water can grow in the ocean? Grab the magical magnifying glass, and see how many different plants and animals you can find in this virtual mangrove swamp. 

It Takes All Kinds to Make a World

It Takes All Kinds to Make a World

The ocean's one diverse place—with alga so tiny that 10 million can fit in a single teaspoon to whales longer than three school buses. Take the surfboard challenge, and ride the waves of biodiversity!

Ocean Creature Feature

Ocean Creature Feature

To survive in the icy Pacific, a sea otter has about a million hairs in every square inch of its fur. Now, that's dense! Take a close look at ocean adaptations while boosting your OLogy card collection.

Dive Into Worlds Within the Sea

Dive Into Worlds Within the Sea

Which squirmy little creatures does the spiny lobster eat? Can you spot the weird greenish glow on the belly of the cookie-cutter shark? Show off your good thinking with a game of good linking.

What's the Big Idea About Astronomy?

What's the Big Idea About Astronomy?

Huge distances, gigantic sizes, and long periods of time—astronomy is a BIG subject. We've brought learning about it down to size with this look at the big ideas you need to know. 

Oscawana: A Dying Lake?

Young Naturalist Awards Essay

Oscawana: A Dying Lake?

2003 Young Naturalist Award-winning essay - Oscawana has all the symptoms of a dying lake. Join this seventh-grader from New York as she hunts for the culprits—and examines what can be done to restore the lake.

Mint Your Own Coin

Mint Your Own Coin

That change jangling in your pocket is more than money—it's a record of where and when you live. Find out why coins are valuable clues for archaeologists. Then, design your perfect coin. 

They Glow!

They Glow!

Most of the deep sea is very dark, with little or no sunlight. But that doesn't mean marine animals are in the dark! Learn how these clever creatures create their own light.

What Do You Know about Astronomy?

What Do You Know about Astronomy?

How much do you really know about our place in space? Test your astronomy knowledge with this interactive quiz. Don't worry, there's no grading—just a helpful look at the answers when you're done! 

Crazy Camouflage

Crazy Camouflage

Unlike humans, some animals can instantly change the color or pattern of their skin. Take a hands-on look at how the masters of disguise known as flounders can don several different looks.

Make a Scale Drawing

Classroom Activity

Make a Scale Drawing

It’s time to excavate the contents of your desk—that is, after you first create a scale drawing of the site. Explore how precise mapping helps archaeologists keep track of their finds.

How Does Where You Live Shape How You Live?

Classroom Activity

How Does Where You Live Shape How You Live?

With access to products and information from around the world, our range of choices is seemingly endless. But how would life be different if you lived in a different time and an isolated place?

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