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

What are the benefits of good posture? Kids will learn about the cognitive effects of good posture through conducting and observing a controlled experiment.

What is condensation? Little mad scientists will learn about condensation, states of matter, and air pressure by conducting this cool science experiment.

Kids will create their own version of Richard Feynman's rubber band heat engine to learn about thermodynamics with this cool science fair project idea.

In this free science fair project, learn how to separate salt from water using heat. A great science project for elementary school kids.

Show your child how to construct a homemade thermometer. It's hands-on fun and a great way to learn about this important instrument!

Kids will learn how to measure the viscosity of liquids by making their own homemade viscometer in this great science fair project idea.

Kids learn about examples of mechanical weathering and conduct an experiment with seeds and plaster in this cool geology science fair project idea.

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

What is biodiversity? Kids will study different areas of their backyards to see which is the most diverse to learn about biodiversity and random sampling.

In this cool physics experiment, use double plane mirrors at various angles to learn about light reflection. Then, see if you can solve a puzzling problem!

In this science experiment, observe convection currents forming and learn about how heat energy moves in liquids from hot to cooler areas through convection.

Learn about where colors come from and how light absorption works in this fun experiment! All you need is a flashlight, construction paper, and cellophane!

Here's an experiment that will have your child experimenting with cake ingredients to learn about the chemical reactions that happen when a cake's in the oven.

What are the effects of colored light on plant growth? Explore plant behavior in this cool botany science fair project and learn about phototropism!

Learn about the effect of artificial light on plant growth versus natural sunlight and delve into some biology and botany concepts in this science project.

Total alkalinity and pH personal care products are controlled to prevent skin irritation. Learn more about basic and acidic substances in this science project.

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.

Check out this fun and easy science fair project idea on germination of a seed and learn to identify exterior and interior parts of a bean seed.

Kids learn about potential energy, and mechanical energy, and how to make power from water with one of our favorite renewable energy projects for kids.

Learn the basic structure of a DNA strand, which is the double helix, how genes form together, and the resemblance DNA has to a twisted ladder. Create a model.

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.

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.

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.

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.

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.

This science fair project idea builds models of various types of bridges and then determines which bridge design is the strongest.