Learn how to make an anemometer with step-by-step instructions in this cool science fair project idea for 4th grade.

How powerful is the reaction between baking soda and vinegar? Find out here!

In this science fair project, kids measure how weather conditions affect how fast a puddle evaporates.

The purpose of this science fair project is to demonstrate how yeast, a fungus, causes bread to rise.

In this science fair projects, students will grow out the bacteria that collect on air conditioner filters.

This science fair project examines how seeds hitchhike on animals and clothing.

Determine whether butterflies like to drink sugar water, salt water, or plain water.

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

Ant behavior is closely related to light intensity. This free science fair project idea examines how fast ants dig when they are exposed to to light and dark.

This experiment tests which gender is better at catching how a magician performs his tricks.

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

Construct batteries that make electricity from fruits with this fun science fair project.

What does a raindrop look like when it splashes on the ground? Is each raindrop unique like snowflakes? Find out how raindrop size varies in this experiment.

How does a flashlight work? Kids will make a complete circuit and explore how voltage contributes to brightness with this science fair project idea.

Do you think you can blow down a sand castle with a mighty wind? Find out which material stands up best to erosion in this erosion experiment.

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

The objective this science fair project is to determine whether a bigger bag will allow a homemade hot air balloon to fly higher than smaller bag.

Crayons aren't just good for creating colorful masterpieces -- they're also great for science!

Free science fair project idea that examines the differences between cats and dogs. Analyze objective qualities rather than subjective ones.

Kids will learn some cool stuff about chemical reactions by determining what happens when you mix different concentrations of hydrogen peroxide and yeast.

Build a 3d animal cell model with this cool science fair project, which helps kids visualize and understand the function of a cell's parts and organelles.

This science fair project investigates why the number of visible stars changes from place to place.

Find out whether matte or shiny nail polish lasts longer.

Is there a relationship between caffeine and heart rate? Students will determine the effect of caffeine on heart rate in this fun science fair project.

In this cool engineering science fair project, kids learn how to build Hero's engine: an enlightening example of Newton's third law.

Kids will make predictions about cricket behavior by conducting this fun and easy experiment which simulates different environments for crickets.

This science fair project idea examines the distance a person travels on an average day and to relate that to an understanding of the size of the Earth.

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.

The objective of this science fair project is to examine the basic principles of air pressure using simple materials like a balloon, straw and string.

This science fair project idea investigates the difference in reaction times between boys and girls.