In a 29-gallon fish tank, this ninth-grader from Virginia created a tropical freshwater ecosystem—and then watched how fish that could never meet in nature interacted.

Why was this 11th-grader from Texas stopping at every mile marker along the road and randomly tossing a hula hoop over his shoulder? To further science, of course!

How safe is the drinking water in your town? This 10th-grader from Utah decided to test water samples to find out the answer for himself. Then, he devised a creative way to improve surface water.

"Some plants don't seem to notice the change in weather, but others, like the aspen, have a new outfit for each season," writes this 10th-grader from New Mexico in her winning Young Naturalist essay.

Years ago, this 11th-grader from Hawaii relied on dried-up hapu'u fronds to build forts in the rain forest. Today, he knows that the rain forest itself relies on those very same fronds.

Dip your toes into the study of salmon habitats with this eighth-grader from Washington State as she researches why there hasn't been a large run in Salmon Creek since the early '90s.

Journey to the Sonoran Desert in southern Arizona with this seventh-grader for an up-close and personal look at the saguaro cactus, which can live about 200 years and grow to be almost 80 feet tall.

Did you know that earthworms migrate during the winter? Find out where they go—and other fascinating details—as this eighth-grader from New York examines their underground world.

Follow along as this 12th-grader from Nova Scotia tries to find out why the common periwinkle is able to live in a heavily polluted body of water known as the North West Arm.

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.