This classic children's game-connecting two cups with a string-demonstrates sound's ability to travel through air vs through a solid.

This science fair project teaches about mold. Students will test different foods to see which grow mold the fastest.

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.

In this activity, your child will be asked to create a boat that can successfully float while holding 25 pennies.

This experiment has students record rat behavior to learn about the benefits of rats and research rat myths throughout history.

Want to make Halloween truly eerie? Science to the rescue! These ghouly hands come alive with a little help from simple chemistry.

In this activity, your child will be challenged to use simple materials to create a catapult for a small, lightweight toy.

In this fun design challenge, your child will get creative with making structures out of toothpicks and gumdrop candies.

Your kid will be captivated as she watches liquids change color before her very eyes during this fun science project that introduces some chemistry basics.

How can we describe the relationship of magnetic field strength vs. distance? Kids will find out with this free science fair project idea.

Are you ready to be a detective for science? Then get out your magnifying glass and start studying fingerprints!

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.

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

This second grade arts and crafts activity is all about caterpillars emerging from their cocoons as butterflies.

The rock cycle will come alive for your child when he uses broken crayons to create the three basic rock types.

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

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.

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

Engineers in training can get started with this simple wheel-and-axle construction activity.

Is your little scientist up for a rocky challenge? Let them make their own geode rocks using eggs and epsom salts!

Is it solid or liquid? Create oobleck and witness the amazingly weird oscillation between the two!

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

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.

Make edible amber fossils with your second grader to explore the fascinating world of science!

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.

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.