Hard-Core Equipment
Beneath their urethane shells, bowling balls once differed mainly in weight (1 and 2). But their cores are now often topped by a sliver of dense material (3) to balance out the wieght lost to finger holes. Many new cores are designed to be unbalanced (4 and 5), to encourage sidespin. Others have an odd-shaped core (6) surrounded by an airy layer of polyester (7), to concentrate weight at the center and lower inertia. A ball with a spherical yet unbalanced core (8) will spin differently depending on where you drill it.
(from "The Physics of...Bowling" by Fenella Saunders) |
