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.