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

Learn about the layers of the Earth and make a model! Create a earth layer book, cake, or clay diagram.

In this cool engineering science fair project, kids learn how to build Hero's engine: an enlightening example of Newton's third law.

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.

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

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.

When you cut a flower to put into a vase, it'll eventually wilt, even with water and sunshine. But is there another scientific secret to keeping flowers fresh?

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

This science fair project idea investigates how magnetism can defy the force of gravity.

How do organic materials become soil? This science experiment measures what materials biodegrade.

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

This science experiment has students test whether a snail moves faster on concrete or dirt.

This science fair project idea explores how length affects the weight a bridge can hold.

This science fair project teaches students the differences between fruits and vegetables.

This science fair project idea demonstrates that plants give off water.

This science fair project examines how seeds hitchhike on animals and clothing.

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

In this cool science experiment, learn about magnetism and poles, and test magnet strength to find out if two magnets are twice as strong as one.

Find the North Star, and measure your latitude! The purpose of this science fair project is to find latitude and learn about geographic locations.

This science fair project idea investigates if webbed feet help a duck (and others) swim.

This is a quick, easy science fair project that conveys the idea of density to preschool and early elementary children.

Science fair project that examines the behavior of water and gravel in creek beds and the formation of sedimentary rocks.

This science fair project idea determines if the size of the parachute will change the rate at which an object falls.

This science fair project idea investigates how the shape of an object affects drag.

There are many benefits to bugs and insects. This science project shows how cockroaches, termites, and other critters benefit our planet.

How can we describe the relationship of magnetic field strength vs. distance? Kids will find out with this free science fair project idea.

This science fair project will help students learn about non-vascular plants, such as mosses.

These science fair experiments demonstrate the chemistry of rust and the oxidation process.

This science fair project teaches students about wilting and browning of salad greens.

This science fair project idea investigates emulsifiers that allow oil and vinegar to mix.