MLA Citation: Bloomfield, Louis A. "Question 1337"
How Everything Works 11 Dec 2017. 11 Dec 2017 <http://howeverythingworks.org/print1.php?QNum=1337>.
1337. You discussed how an egg doesn't bounce because it doesn't have time and instead it breaks. Why, then, does a mouse ball (in a computer mouse) or a bowling ball not bounce? It doesn't break, so why doesn't the support force make it bounce back upward. Does this relate to elasticity?
Actually, both a mouse ball and a bowling ball will bounce somewhat if you drop them on a suitably hard surface. It does have to do with elasticity. During the impact, the ball's surface dents and the force that dents the ball does work on the ball—the force on the ball's surface is inward and the ball's surface moves inward. Energy is thus being invested in the ball's surface. What the ball does with this energy depends on the ball. If the ball is an egg, the denting shatters the egg and the energy is wasted in the process of scrambling the egg's innards. But in virtually any normal ball, some or most of the work done on the ball's surface is stored in the elastic forces within the ball—this elastic potential energy, like all potential energies, is stored in forces. This stored energy allows the surface to undent and do work on other things in the process. During the rebound, the ball's surface undents. Although it's a little tricky to follow the exact flow of energy during the rebound, the elastic potential energy in the dented ball becomes kinetic energy in the rebounding ball. But even the best balls waste some of the energy involved in denting their surfaces. That's why balls never bounce perfectly and never return to their original heights when dropped on a hard, stationary surface. Some balls are better than others at storing and returning this energy, so they bounce better than others.

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