Materials Required:
l Push-pull cap from dishwashing liquid
l Baseball bat
l Clay
l Ball bearing or small marble
Procedure:
You learned about a bat’s center of percussion in the last experiment. Here is another method to locate that spot on your bat.
- Pull out the center piece of the push-pull cap and attach it to the end of your bat with a piece of clay.
- Set a ball bearing or small marble on the plastic piece. (The ball should be small enough so that it rests securely inside the curve, but large enough to prevent it from dropping down the opening.)
- Rest the handle of the bat on the ground and raise the wide end. Let the bat fall. Repeat the process several times, each time changing the placement of the ball and its holder along the length of the bat. What do you find?
This Is What Happens:
The freely falling object (the ball) falls at a constant speed. The end of the bat, however, falls faster than the handle. When the ball/cap device is stuck near the end of the bat, the end of the bat falls away from beneath the ball. You hear the click of the ball hitting the ground after the bat has hit. But when you place the ball at the center of percussion, the ball and the bat both drop at the same rate. There is no click!
