In this science fair project, young children discover what happens when two fluids that have different densities get together.

What is a wedge? Kids find out by experimenting with different wedges in this simple science fair project idea.

What causes dilated pupils? Young scientists will find out by applying what they already know about changes in pupil size and making models of the pupil.

What is topography? Kids find out by learning to make and read a topographic map in this awesome science fair project idea.

What is surface tension? Kids will discover how water-skating insects use surface tension to keep from sinking by making a model water walker.

In this experiment, your child will create two compost bins and see if he can determine what attracts fruit flies.

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.

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

What is a compound microscope? Kids find out by making one of their own in this cool science fair project.

What do worms eat? Kids find out what kinds of rotting leaves and vegetables worms prefer in this cool compost science fair project.

In this classic Ivory soap experiment, kids learn what happens to different types of soap in the microwave, and why!

What is elasticity? Students will investigate how this concept applies to bouncing ball physics by testing the bounces of balls made out of different materials.

Certain fruits can change gelatinâs ability to set. In this experiment, kids will discover what happens when gelatin meets pineapple enzyme.

Be a chemist for a day and study the simple reaction between sugar and heat. Try heating sugar and see what happens!

What makes your shadow dance around all day? Let's play detective and find out why that sneaky shadow never stays in one place for long.

Observe with your third grader what happens when food starts to decompose, and boost science skills simultaneously with this experiment!

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

In this Halloween-themed activity, young learners will find out what happens when they mix two household items together to create a surprising chemical reaction.

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 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.

In this 3rd grade science activity, you'll experiment with the little-known fourth state of matter: polymers! Mix borax with white glue and watch what happens.

This science project teaches young students about germs, bacteria, and the importance of washing their hands. Students will test what is the best way to wash.

Science fair project that demonstrates the effect of detergent pollution on fresh water birds' ability to stay afloat.

Enter the buzz worthy world of bee watching and find out what time bees like to wake up!

Water can go from solid to liquid to gas...but how does popcorn go from kernel to snack? Invite your first grade scientist to find out.

This educated-guessing game is great for preschoolers. This activity helps your child work on her reasoning skills.

Learn about the layers of the Earth and make a model! Create a earth layer book, cake, or clay diagram.

If your child aspires to be the next Frank Lloyd Wright, we've got some tips on building sand castles that last.

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

The next time you've got a restless second grade earth scientist on your hands, use this experiment to demonstrate crystals and make a tasty treat, too!