In this free science fair project idea, we learn about surface tension and how it can support mass—in this case, a floating paper clip.

This science fair project idea investigates whether air has mass and weight.

Will increasing the amount of salt in water effect how slow or fast the water freezes?

Will storing cucumbers and tomatoes in the fridge destroy their unique flavors? Find out in this science fair project idea!

For this science fair project, kids will learn how to make a lemon battery. They can conduct this classic experiment using readily available materials.

The moon doesn't produce its own light, so why can we see it shining in the sky? Learn about reflection and planetshine in this fun and easy science project!

How do animals keep warm? In this experiment, find out whether fat insulation resists cold temperatures and learn how this works in the animal kingdom.

This science experiment tests why guacamole goes brown and if leaving the pit in will stop guacamole from turning brown.

This science fair project teaches students about wilting and browning of salad greens.

In this project, sunlight is blocked from a leaf in order to see the affect that sunlight has on leaves.

How do organic materials become soil? This science experiment measures what materials biodegrade.

Young scientists will investigate people's preferences for saltiness, and make some inferences about genetics and diet.

This science fair project idea determines if crystals will absorb food dye and if colors will mix by the process of diffusion.

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

These science fair experiments demonstrate the chemistry of rust and the oxidation process.

How does the size of a vibrating surface affect the pitch of a drum? Learn about drum size and pitch with this easy science fair project idea.

Step into the fantastic world of colors with a project that explores what shade you -- and your friends -- like best.

Can a horse lead itself to the carrot? Train your horse with carrots and boxes and test horse memory in this fun zoology science fair project.

While your cells are much too small to see without a microscope, you can create the look of a cell in your very own home with just an egg and vinegar!

Kids construct a single fixed pulley system to learn how pulleys can make work easier in this cool physics and engineering science fair project idea.

Learn about this simple machine and make a pulley of your own to use for fun science trials.

Science fair project idea that examines different physical characteristics of a chosen animal. Make educated guesses about evolution based on animal's form.

This science fair project idea teaches how the gases and pollution in the air affect the earth's atmosphere temperature.

This project determines what category of person is most likely to be ticklish.

What is persistence of vision? With this hands-on science fair project idea, students will demonstrate this cool and dramatic phenomenon in their own classroom.

Did you even wonder why some rocks are round and smooth while others are broken up into small pieces?

How do icicles form and what do they look like? Do this free science fair project and watch the formation of icicles occur right before your eyes.

Kids will learn how to show the direction of magnetic field lines and create a permanent model using iron filings in 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 science fair project, students discover how sedimentary layers form as sediments like mud, silt and sand settle over time.