SCIENCE & BASEBALL
Concept of bouncing balls can be used to teach preservation of energy and its transformation from one form to another.
When you drop a ball, gravity pulls it toward the floor. The ball gains energy of motion, known as "kinetic energy." When the ball hits the floor and stops, that energy has to go somewhere. The energy goes into deforming the ball -- from its original round shape to a squashed shape. When the ball deforms, its molecules are stretched apart in some places and squeezed together in others. As they are pushed about, the molecules in the ball collide with and rub across each other.
|
This chart shows the relative bounciness of various types of balls. |
Exactly what happens to these molecules as they stretch and squeeze depends on what the ball is made of. Suppose you drop a ball of putty. Rather than bouncing, it hits the floor and flattens. All of the organized motion of the falling ball becomes the random motion of jiggling molecules. The random motion of jiggling molecules is a measure of"thermal energy." The putty gets warmer, but it doesn't bounce. Putty is inelastic -- it doesn't return to its original shape.
The baseball is more elastic because its core is made from materials that act quite differently than the putty. Most of these materials are made from "long-chain polymer molecules." When you hold the ball in your hand, these long molecules are tangled together like a ball of molecular spaghetti. During a collision, these molecules stretch -- but only for a moment. Atomic motions within the rubber molecules then return them toward their original, tangled shape. Much of the energy of the ball's downward motion becomes upward motion as the ball returns to its original shape and bounces into the air.
Many other science concept can be taught using examples from baseball, ( ie. Projectile motion, momentum etc.)
Source: http://www.exploratorium.edu/
