Sunday, June 15, 2003

Did you ever wonder while you were watching Michael Jordan running up the court, dibbling a basketball and shooting a game-winning final-second shot how a ball bounces?

If so, here is the answer. A basketball bounces because of air and gravity. Air makes the ball bounce because air does not want to stay up. Air wants to go down. It is like that old saying---"what goes up, must come down." This old saying is true and also describes gravity.

Scientific properties of a basketball also help to explain why if you bounce the ball hard, it will go high, But if you make a small bounce, the ball will not bounce much. This is because of elasticity. Elasticity is defined as an object's property of changing shape when the deforming force is removed. A basketball is elastic. So, when it hits a hard surface, the ball's shape is deformed and kinetic energy (energy in motion) is changed to and stored as potential energy (energy that is stored). Once the basketball returns to its original shape, potential energy is changed back into kinetic energy and makes the ball bounce. Based on this scientific principle, pulling a little muscle into your dribbling will help you make the basketball bounce higher.

Air and gravity play important roles in basketball. You have probably noticed how important air is when your ball is deflated or without air. Does a basketball without air bounce? NO! So, you need to keep your basketball filled with air. But, air only supplies a part of the energy storage in an under-inflated basketball. Another player in a basketball's energy supply is the ball's leathery skin. But, the skin does a bad job of storing the energy it gets from being bounced. It is like a leather belt. It is not very elastic. It quickly loses the energy it gets as thermal energy. These scientific properties of a ball make having a well-inflated basketball important.

Science in sports is not limited to how a basketball bounces. The following website provides more details of how science is a key player in the entire game of basketball: http: //www.physics.utoronto.ca/~rbhat/bball/physics/.

Little Lion Experiment:

Materials:

• Different types of balls (basketball, baseball, tennis balls, football, etc.)
• Measuring stick
• Paper and pencil
• Teammate

Procedures:

1. Take one ball at a time and bounce it.
2. Have a teammate use a measuring stick to determine how high that ball bounced.
3. Record the type of ball you bounced and how high it bounced.
4. Figure out which type of ball bounced the highest. Why? (Hint: Remember air and gravity. Shape is also important.)
5. Pick a sport and play it often. Participating in sports is good for your heart and head.