This science fair project idea demonstrates how air resistance contributes to denser objects falling faster than less dense objects.

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.

Is it possible to trick the forces of nature that make your bubbles round to create a square bubble?

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

Start your toy engines -- this is going to be a fast and friction-filled race!

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

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

In this science fair project, students use the streak test to tell minerals apart from each other.

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

Kids construct a single fixed pulley system to learn how pulleys can make work easier in this cool physics and engineering science fair project idea.

Learn about this simple machine and make a pulley of your own to use for fun science trials.

Science fair project that determines whether lettuce that is harvested gradually yields more produce than lettuce that is harvested all at once.

In this science fair experiment, children demonstrate the relationship between the amount of stuff and the amount of pressure in a closed system.

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.

Do plants get crowded? Have your curious kid investigate how plants respond if they're forced to grow together in a confined space.

Is it a square or a circle? See if you can trick your friends with this zany science project!

Get down to the rubber with this science project that tests the effectiveness of different types of erasers.

In this science fair project, students learn how pressure can make the minerals in a rock line up in the same direction and form bands and foliation.

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

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.

What animals are most popular? This project affords practice in data-collection, record-keeping and data-analysis through the investigation of this question.

In this experiment, your child will create two compost bins and see if he can determine what attracts fruit flies.

Do you think you can blow down a sand castle with a mighty wind? Find out which material stands up best to erosion in this erosion experiment.

Use pepper and soap to discover some fun facts about the properties of water.

Plants and light seem to be good buddies, but how far does the friendship really go?

Can a horse lead itself to the carrot? Train your horse with carrots and boxes and test horse memory in this fun zoology science fair project.

Play with balance and simple engineering as you hurry to create a sturdy rock tower.

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.

In this science fair project, you'll make a "ghost" appear in a test tube, and learn about what happens when hot water and cold water interact.

In this fun science experiment, kids will determine the best method for ripening avocados and discover the cool chemical reaction that makes this possible.