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.

Kids build a desert food chain, desert food web, and desert food pyramid in this cool science fair project to learn about trophic levels and consumers.

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!

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.

This science fair project idea produces varying pitches of sound.

Little scientists will make inferences about hearing loss, pitch, and frequency in this great science fair idea that puts the human ear to the test.

This science fair project idea explores which fruit molds the fastest.

Discover whether different amounts of water added into a wine glass will produce a different pitch when their fingers are rubbed along the rim.

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.

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.

Demonstrate how to tell the age of an egg without having to crack it open.

Science fair project that determines whether tapping a pomegranate with a spoon helps it release its seeds.

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

Kids will love making sugar crystals in this sugar crystal science fair project which teaches important chemistry concepts like saturation and solubility.

Science fair project that determines whether lettuce that is harvested gradually yields more produce than lettuce that is harvested all at once.

Throughout history, people have used song as a teaching and memory tool. This project explores whether song improves a person's ability to retain information.

Science fair project that determines whether landscaping fabric impacts the ability of plants to receive water.

Stories change as you retell them. The objective of this science fair project is to demonstrate how information gets interpreted, distorted and changed.