In this science fair project, learn how to make gears and find out why they transmit torques in predictable ways.

Learn how to make a hygrometer to measure relative humidity in this project. Make a sling psychrometer hygrometer with gauze, thermometers, and a bottle.

Learn how to make an anemometer with step-by-step instructions in this cool science fair project idea for 4th grade.

Demonstrate how you can make your own compass using a magnetized needle. It also allows you to compare magnetic north and geographic north.

Create safe lightning for kids! They'll learn how to make lightning at home with this fun science fair project idea illustrating static charges and grounding.

This basketball project explores the best way to make the perfect shot every time.

For this science fair project, kids will learn how to make a lemon battery. They can conduct this classic experiment using readily available materials.

In this hands-on design challenge your child will make their very own Rube Goldberg Machine.

Kids get step-by-step instructions for how to make a rubber band car and explore the physics of potential energy with this fun engineering science fair project.

It's not actually that hard to get energy from garbage! Kids learn how to make biogas in the form of methane with this cool and easy science fair project idea.

Kids will learn how to make a steam powered rocket boat, also called a putt putt boat or a pop pop boat, in this great science fair project for 4th graders.

This science fair experiment idea's objective is to understand the general concept of an acid and a base.

This science fair project explains the process of how the lungs expand and contract with the help of the diaphragm.

Experiment with buoyancy to learn how a submarine rises and sinks in this classic science experiment.

Learn whether writing things down really makes things easier to remember.

In this activity, your learner will be challenged to create their own tic-tac-toe grid out of building blocks.

In this science fair project, students make their own rain gauge to measure rainfall.

Construct batteries that make electricity from fruits with this fun science fair project.

Do you love to make Jell-O? Find out in this science fair project idea if it is possible to make Jell-O with just warm water.

Did you ever add salt to pasta? Did it help cook the pasta faster? If not, find out in this science fair project idea.

In this design challenge, your child will make a bottle rocket using typical household items.

In this science fair project, kids start a chemical reaction that will make a balloon inflate itself!

Science fair project idea which teaches you how to make butter by separating cream into butter and buttermilk.

In this science fair project you will make a model of a cell membrane using very simple material.

Discover that the absorbency of fabrics depend largely on the shape and structure of the individual fibers that make up the fabric.

Discover how to make fake snot with this cool science fair project idea to learn about polymers, enzymes, and more.

Learn how to make a ping pong ball anemometerâa device used to measure wind speedâin this free science fair project idea.

The purpose of this science fair project is to determine which conditions and materials quicken the composting process to make the best compost.

Science fair project which teaches you how to make your own homemade glue by combing curdled milk with baking soda.