In this fun science experiment, kids will determine the best method for ripening avocados and discover the cool chemical reaction that makes this possible.

This easy and inexpensive paper towel science project introduces kids to important physical concepts like cohesion, adhesion, and capillarity.

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

How does water pressure change with depth? Kids learn how pressure works underwater with this cool and easy demo.

What's the best way to make DIY compost? Kids will learn about aerobic and anaerobic decomposition while learning to appreciate the value of composting.

Create a soda bottle garden that defies gravity! This hanging terrarium is housed in a soda bottle and perfect for crafty kids with a growing green thumb.

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.

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

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

How does dishwashing liquid work? Kids discover the chemical mechanism behind cleansing power in this easy science fair project idea.

Kids discover what a homogeneous mixture is by adding sugar to distilled water and identify the various factors affecting solubility.

Kids learn how to manipulate additive and subtractive colors to send secret messages with red colored filters in this cool science fair project idea.

Show your kids the power of baking powder by conducting a simple experiment. Make four batches of cornbread, all identical except for one thing: baking powder!

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

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.

In this experiment, kids will see if pruning tomato plants makes them more fruitful and learn about the factors that contribute to a plant's fruit production.

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

It's easier than you think to make homemade play dough -- just a few pantry staples makes a natural version of the toy that kids have loved for generations.

Is it magic? No...it's the amazing, gravity-defying capillary action experiment! Kids will love this dramatic and enlightening science fair project.

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.

How does a compass work? What's a magnetic field? Kids will build their own compass at home to find the answers in this great science fair project idea.

Creating a home for a toad is an easy and fun project for kids. Here's how to make your very own toad abode.

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 thermometer to to explore liquid density in this great science fair project. Which liquids are affected by temperature the most?

In this science fair project, kids observe the expansion of liquids when frozen and determine if some liquids expand more than others in the freezing process.