# Science Projects for Kids: Nutrition and Health

High Bounce

You already know that the force of gravity is what causes a ball to drop to the ground -- but did you know that same force can give the ball a high bounce? That's because the force of gravity can be converted to energy.

When a ball strikes the ground, the downward force from gravity is converted into upward force, which then works against gravity to send the ball up in the air.

As you'll see, different materials and sizes of the balls affect how well each one converts the energy into upward force -- and that affects how high each ball will bounce.

### What You'll Need:

• Balls of various sizes and materials
• Pencil
• Graph paper
• Large sheet of cardboard
• Tape measure

Step 1: Collect some different balls, such as a tennis ball, beach ball, softball, rubber ball, football, basketball, and golf ball.

Step 2: Make a graph that lists the names of the different balls across the bottom and that lists the height in feet along the sides.

Step 3: Test the different balls to see which one bounces best on a concrete floor, porch, or driveway.

Step 4: Set the cardboard sheet against a wall, or ask two friends to hold it upright. Then drop the balls, one at a time, from the same height, in front the sheet of cardboard.

Step 5: Mark on the cardboard how high each one bounced.

Step 6: Measure each bounce, and indicate it on your graph.