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

Science fair project which will teach you more about the foods that you eat, and learn which ones are healthier choices.

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

What causes the seasons to change? Kids find out by modeling the earth's tilt using a globe, flashlight and graph paper in this cool science fair project idea.

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

What causes dilated pupils? Young scientists will find out by applying what they already know about changes in pupil size and making models of the pupil.

In this free science fair project, build a star clock and learn how to tell time on a clear night by observing the big dipper!

How do icicles form and what do they look like? Do this free science fair project and watch the formation of icicles occur right before your eyes.

In this cool project, create a lighted, scale model of the different layers of the Sun, including the core, radiation and convection zones, and photosphere.

Saturn is the ringed planet in our solar system, a gas giant with rings made of ice and dust. Let's make a cool scale model with an old CD and some glitter!

This science fair project idea experiments with spinning color wheels and optical illusions.

How good are humans at sound localization? Kids can try this cool science fair project idea to see how good their friends are at judging sound direction.

This science fair project idea recreates the movement of planetary bodies in order to learn why they sometimes appear to move backwards.

Why do ants like sugar? Do ants like artificial sweeteners too? Kids find out with this great inquiry-based science fair project.

Prove that the Earth is not flat. The objective of this science fair project is to measure the angle of the sun and calculate the circumference of the Earth.

Tree rings can tell the age of the tree but also information about the world. This science experiment uses tree stumps to discover new facts.

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

In this project, all you need is a protractor to learn how to use the altitude of Polaris to find latitude on Earth. Polaris is also known as the North Star.

How do the phases of the Moon and gravity cause spring tides and neap tides? Does the Sun play a role in the tides? Figure it out in this fun science project!

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

What is persistence of vision? With this hands-on science fair project idea, students will demonstrate this cool and dramatic phenomenon in their own classroom.

How does a compass work? What's a magnetic field? Kids will build their own compass at home to find the answers in this great science fair project idea.

Science fair project which teaches you about the principles of physics within a vacuum by creating a vacuum chamber.

In this simple circular motion experiment, you'll observe tangential velocity and learn about how acceleration and centripetal force affect an object.

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

In this fun science fair project, make two different scale models of our solar system using Astronomical Units and planets' relative size!

This simple heat transfer experiment is a great introduction to the concepts of heat transfer and conduction.

Have you ever noticed the way a dropped stone makes a fun pattern in a pond or lake? What's the science behind these splashy occurrences?

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.