This science fair project idea determines whether eating before or after exercise is more beneficial to health and performance.

Observe which kind of fresh long-stemmed flower will last the longest after being picked.

Is exercise a cellular activity? Check out this fun science fair project idea to compare the carbon dioxide production before and after exercise.

Determine whether a hot liquid cools off faster when liquid is added before or after a two minute wait.

This two-ingredient dough, sometimes called "moon sand," is a quick and cheap way to let kids explore their senses, build fine motor skills, and play.

This science fair project idea explores whether boiling and freezing water will have an effect on how much it weighs.

This science fair project evaluates if and how eating a large meal affects ability to perform mental tasks.

In this cool science experiment, learn about magnetism and poles, and test magnet strength to find out if two magnets are twice as strong as one.

Compare different remedies for cooling the mouth after eating spicy food.

This project is about after-images and what possibly affects them.

This experiment examines if space objects become round after reaching a certain mass.

This project determines how much the rebound rates of tennis balls change after ten games.

Assess physical and mental states of subject before and after drinking coffee. Compare initial expectations with their reported conditions.

This experiment will evaluate bacterial content on toothbrushes before and after different cleaning methods to determine which method of disinfecting is best.

What can you do with hair after its cut? This science project teaches you practical uses for human hair.

Research fruits and their ripening stages, follow and document the different stages. Analyze what causes fruit to continue ripening after being picked.

Discover whether the â5-second ruleâ is effective at determining whether food is still safe to eat after being dropped on the ground.

Research active ingredients in anti-aging creams. Test skin creams on volunteers, document the effectiveness of the creams with before an after photographs.

Study the effect of music on blood pressure. Compare blood pressure readings before and after the listening session. Analyze results, write a detailed report.

This project compares the strength of one, two, and three-ply toilet paper.

In this project, you will observe and record changes in sunspots over two weeks.

You've heard all about oil spills, but can they really be that bad? After all, vegetable oil is in almost every yummy baking good from cookies to brownies.

This science fair project idea focuses on two classes of sugars monosaccharides (fructose) and disaccharides (sucrose or table sugar).

Boost your preschooler's attention to detail by getting her to explore the differences between two different pumpkins: large and small.

Your preschooler can learn how to siphon water with just two bottles and a plastic tube in this fun, educational science activity.

This science fair project idea determines an average personâs ability to use their anaerobic power system over a period of 2 weeks.

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

This science fair project compares the allelopathic affects of juglone, a chemical agent produced by the Black Walnut tree, on two plants.

Did you ever drink spoiled milk? Find out whether whole milk spoils at the same rate as 2% and skim milk.

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