Is it amplitude? Weight? Length of string? Kids will discover what factors changing the period of a pendulum depends on in this fun and easy physics experiment.

In this science fair project, kids start a chemical reaction that will make a balloon inflate itself!

Want to see a great example of Newton's first law? Kids will learn about basic physics with this fun, ballistic experiment.

In this fun science fair project idea, kids will experiment with various methods in order to discover the fastest way to cool a soda.

What's the relationship between temperature, air humidity and static electricity? Kids will find out with this free static electricity science fair project.

This is a fantastic and easy science experiment where kids will learn about elasticity by testing how high bouncy balls of different materials can bounce.

In this cool science fair project idea, kids conduct the ruler drop test on volunteers to determine whether reaction time can be improved with practice.

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.

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.

This science project uses Mohsâ Hardness Test to show kids how to compare the hardness of different types of minerals.

Kids explore how a single movable pulley can confer a mechanical advantage over a fixed pulley in this cool engineering science fair project for 2nd grade.

What are the effects of fertilizer on plant growth? What's the best fertilizer type (solid, liquid or powder)? Kids find out in this science fair project idea.

This science fair project teaches kids experimental design and how to test if subjects can really sense if they are being watched.

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.

How does distance affect the spreading of light? Kids see diffraction and the inverse square law of light in action with this great science fair project idea.

What do ants eat? Kids find out by observing a colony of ants in this cool zoology science fair project for 4th grade.

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

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.

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.

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.

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.

This science fair project idea researches the different layers of the atmosphere and creates a visual representation of the atmospheric layers.

What animals are most popular? This project affords practice in data-collection, record-keeping and data-analysis through the investigation of this question.

In this project students experiment with making music using only glasses of water.

This science project encourages students to investigate the Mozart Effect, the idea that classical music promotes learning.

The objective of this science fair project is to observe the differences in heat absorption for darker colors vs. lighter colors.

In this outdoor science activity you'll find tips on how to create a nature journal by choosing a native plant or animal and tracking that species.

Science fair project about work and energy which uses a simple mathematical formula to predict how far a jar will roll down an incline.

In this popcorn experiment, students can explore how two things made out of the same material can have very different appearances and densities.