Air invisible; it doesn't make sounds; you can't pick it up and throw it. So how do we know it exists? Help your second grade scientist figure it out.

This classic children's game demonstrates how sound travels through air vs. through a solid.

This classic children's game-connecting two cups with a string-demonstrates sound's ability to travel through air vs through a solid.

In this sound experiment children listen for differences as they tap on a bag of air, a bag of water, and a wooden block held up to their ears.

How does a kazoo, the strings of a guitar, or the speaker of a radio make sound? The purpose of this science fair project is to show how vibration makes sound.

What's the science behind those out-of-sight roots? Find out if you can trick roots into growing in different directions.

Did you know a mouse eats almost fifty times as much as a cow? Find out how and test out the strange science with your friends!

Do different types of oil mix or stack? Find out in this science fair project idea!

Test your friends to find out if you can replicate the placebo effect's incredible results.

Do earthworms like moisture or darkness? Find out as we explore the relationship between earthworms and light.

Are you ready to be a detective for science? Then get out your magnifying glass and start studying fingerprints!

It's rhyme time! With this science fair project idea, your child will find out which words can be considered easy rhyming words, and why.

Will storing cucumbers and tomatoes in the fridge destroy their unique flavors? Find out in this science fair project idea!

What is a wedge? Kids find out by experimenting with different wedges in this simple science fair project idea.

In this fun design challenge, your child will get creative with making structures out of toothpicks and gumdrop candies.

Find out whether soil amendments can improve soil conditions and help you grow a bigger beanstalk in this ecology experiment!