In this free science fair project, learn how to separate salt from water using heat. A great science project for elementary school kids.

Your child will do a fun science experiment using soap and pepper flakes to help understand the concepts of water molecules and the surface tension of water.

This homemade barometer allows your little scientist to contemplate and compare different air and weather conditions.

What is elasticity? Students will investigate how this concept applies to bouncing ball physics by testing the bounces of balls made out of different materials.

Make your own helicopter using a paper clip and a sheet of paper. Hold the spinner up in the air, let it go, and watch it spin gracefully to the ground.

Engineers in training can get started with this simple wheel-and-axle construction activity.

Has your kid noticed how much bigger the moon looks when it's low in the sky? Here's an activity you can do to show them that it's just an optical illusion.

Help your fifth grader execute this experiment involving a lit candle (submerged in water!) to show him the wonders of heat energy transference.

What causes sound? Here's a simple science experiment that adds a visual element to the science of sound to help kids better understand this tricky concept.

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.

In this air pressure science experiment with a balloon and a jar, children will use heat to create a partial vacuum and suck a balloon into a jar.

Using an empty tennis ball can and a swimming pool, you will determine if it's possible to have a conversation under water.

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

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.

Get your sense of humor ready for this fun science experiment that demonstrates the fundamental physics of air pressure.

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

This project demonstrates the correspondence between the volume of water displaced by a submerged object and the volume of the object displacing it.

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.

Put your second grade scientist to work this Fourth of July with our colorful "liquid fireworks" project!

How does rust form? Kids will learn about the roles oxygen, water, and electrons play in rust chemistry in this cool science fair project idea.