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.

What is biodiversity? Kids will study different areas of their backyards to see which is the most diverse to learn about biodiversity and random sampling.

What are the effects of fertilizer on plant growth? What's the best fertilizer type (solid, liquid or powder)? Kids find out in this science fair project idea.

Science fair project that compares the ecology of different soil samples by identifying which sample has the most invertebrates living in it.

Science fair project that examines how to grow bacteria in a controlled setting, using simple materials from around the home.

Kids build a desert food chain, desert food web, and desert food pyramid in this cool science fair project to learn about trophic levels and consumers.

This taste buds science experiment demonstrates how strongly our sense of smell controls what we taste.

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 science fair project idea builds models of various types of bridges and then determines which bridge design is the strongest.

This science fair project idea investigates whether plants can survive being frozen.

Brine shrimp usually live in saltwater. Investigate how salt concentration (salinity) affects the rate at which brine shrimp eggs hatch.

In this science fair project, students examine under what conditions individual plants release seeds and how far the seeds are released.

Make your own marshmallows and mix up some very interesting third grade chemistry lessons while you're at it!

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

The objective of this science fair project is to experiment with balancing everyday objects and observing the the effects of gravity on materials.

Help your child create a tasty treat that will demonstrate exactly how frogs survive a freezing season.

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 science fair project, apply the principles of leverage and force by building six simple machines designed to set weights in motion.

This project determines the age of a tree using a growth factor chart instead of cutting the tree down to count the rings in its base.

Kids will discover the meat science behind the meat they eat, and find out how to use safe chemistry to make meat more tender.