This science experiment tests why guacamole goes brown and if leaving the pit in will stop guacamole from turning brown.

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.

Before Twitter, birds were the ones tweeting, not humans. Have your child discover the magical sounds of nature while recording birds around his neighborhood!

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.

Using a toy race car kids create a visual model of the Doppler Effect.

How does the size of a vibrating surface affect the pitch of a drum? Learn about drum size and pitch with this easy science fair project idea.

Take a closer look at your furry friend (or the furry friend of a neighbor -- with permission) to discover if communication exists between cats and humans.

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.

Children will learn all about cause and effect as they experiment with potion-making in this Halloween themed activity.