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.

In this cool experiment, learn how to find specific gravity of minerals using liquids of different densities to see which substances and items sink and float.

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 windmill model science project, you will build a windmill to learn about wheel-and-axle machines and how these simple machines are used to do work.

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.

What is the hydrologic cycle and how does it work? Check out this fun and easy science project where you will model and learn about Earth's water cycle!

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.

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.

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.

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.

Does putting soapy water on plants help or hinder plant growth? Kids learn about greywater and how it affects plant growth in this cool science fair project.

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.

This experiment examines whether storing your orange juice at different temperatures affects its acidity.

Science fair project that determines whether cooling eggs helps them be peeled more easily. Compare the time it took to peel each egg.

This science fair project idea determines the probability of a coin landing heads or tails.

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.

Science fair project which evaluates different athletic shoes in order to find out whether any of them affect a person's ability to run.

The objective of this science fair project idea is to determine if sound travels best through the air, water or a solid.

In this experiment you observe and determine how well your cat uses his whiskers to navigate through a maze.

This science fair project idea examines whether adding gelatin causes a solid to have a higher melting point and/or melt slower.

In this science fair project, students will try to discover if test subjects can detect the presence of Monosodium Glutumate (MSG) in food.

Science fair project in which you will attempt to throw a ball the greatest horizontal distance possible by using different angles.

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.