Bowling Ball

A bowling ball is a spherical ball made from plastic, reactive resin, urethane or a combination of these materials which is used in the sport of bowling. Ten-pin bowling balls generally have a set of three holes drilled in them, one each for the ring and middle finger, and one for the thumb; however, rules allow for up to five finger holes. They generally range from six pounds to 16 pounds in weight. The maximum limit allowed in tournaments or league games is 16 pounds, but balls of up to 20 pounds are available. A five-pin bowling ball has no finger holes and is smaller so that the bowler can hold the ball in the palm of his or her hand. Candlepin bowling balls also fit in the hand, but are slightly smaller and lighter than five-pin balls. Most bowling alleys provide free balls for patrons to use, called "house balls", although bowlers may purchase their own. These are often customized, and can feature specially sized finger holes (in the case of ten-pin balls) or monograms. Because purchased balls are usually drilled to match the owner's fingers, most can throw a customized bowling ball that is one to two pounds heavier than the house ball they previously used.

Bowling balls come in many varieties of colors, and are often either a single flat color, a swirl-like design of multiple colors, gray or a single color with an iridescent look. It is even possible to obtain transparent bowling balls, some are even made white the clear polyester or plastic shell with a small object inside of them for a distinctive look. These objects look to be rather large but are in fact a lot smaller outside of the ball. Some objects have included skulls, footballs, and small bowling pins.

Inside the ball is a core which is dynamically imbalanced to cause the ball to try to stabilize as it is rolling down the lane. This makes the ball roll over a different point on the surface every time it revolves and "flares" or causes multiple rings of oil as it travels down the lane. Bowling ball cores are constructed with different densities as well. Some are center heavy (low rg) and some cores are made with the weight distributed more towards the cover of the ball (high rg). Low rg balls will spin more easily than the high rg balls.