Kids learn how to manipulate additive and subtractive colors to send secret messages with red colored filters in this cool science fair project idea.

In this experiment, kids will see if pruning tomato plants makes them more fruitful and learn about the factors that contribute to a plant's fruit production.

Kids will conduct a cool limewater carbon dioxide test that can be performed with common household materials to learn about the chemistry of this common gas.

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.

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.

How do animals keep warm? In this experiment, find out whether fat insulation resists cold temperatures and learn how this works in the animal kingdom.

Here is a fun middle school science project on factors affecting solubility. Learn how dissolved solids can "crash out" to form crystals when conditions change.

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.

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.

What are buttress roots? In this fun science project, make a model of a rainforest tree and learn how they help trees survive in the tropical rainforest!

Kids will learn about the interaction of lactose and lactase in milk and discover why we describe enzymes as catalysts in this fun science fair project.

Learn how to tell time by the sun with this cool science fair project idea that tracks how the accuracy of a sundial changes over time.

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.

In this fun science fair project idea learn about universal solvents and solutes and find out the solubility of several common liquid substances.

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.

In this project, learn about animal vision and different kinds of eyes: ocelli, compound eyes, and camera eyes. Find out what a jellyfish or grasshopper sees!

With this cool floating rocks project, your child will get some hands-on experience with buoyancy and learn why certain rocks like pumice are able to float.

Kids will learn how to show the direction of magnetic field lines and create a permanent model using iron filings in this great 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.

4th graders construct an ocean food web to learn about consumers and trophic levels, food webs, and food chains in this cool ecology science fair project.

In this experiment, young ecologists will learn about a type of edge effect: how trees and plants at the edge of a forest can act as a weed filter.

Can a toy car determine the strength of a magnet? In this cool magnet science fair project, young scientists will learn how to measure the strength of a magnet.

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.

Kids learn how to prevent erosion by growing grass. They'll test soil with grass against raw soil in this revealing science fair project idea for 4th grade.

Check out this cool science project idea to learn about rocks and explore the cycles of formation, breakdown, and reformation of rocks in the Earth's crust.

How does frost form? How fast does it form? Do this simple science project using a plastic glass, rock salt and some water to learn about deposition.

The moon doesn't produce its own light, so why can we see it shining in the sky? Learn about reflection and planetshine in this fun and easy science project!

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.

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.

What chromosome combinations determine a fetus gender? Use probability to think about whether a sperm and ovum will create a male or female in this project.