Bowling ball
Overview
A bowling ball is a spherical ball made from plastic
Plastic
A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...

, reactive resin, urethane
Polyurethane
A polyurethane is any polymer composed of a chain of organic units joined by carbamate links. Polyurethane polymers are formed through step-growth polymerization, by reacting a monomer with another monomer in the presence of a catalyst.Polyurethanes are...

 or a combination of these materials which is used in the sport
Sport
A Sport is all forms of physical activity which, through casual or organised participation, aim to use, maintain or improve physical fitness and provide entertainment to participants. Sport may be competitive, where a winner or winners can be identified by objective means, and may require a degree...

 of bowling
Bowling
Bowling Bowling Bowling (1375–1425; late Middle English bowle, variant of boule Bowling (1375–1425; late Middle English bowle, variant of boule...

. Ten-pin bowling
Ten-pin bowling
Ten-pin bowling is a competitive sport in which a player rolls a bowling ball down a wooden or synthetic lane with the objective of scoring points by knocking down as many pins as possible.-Summary:The lane is bordered along its length by semicylindrical channels Ten-pin bowling (commonly just...

 balls generally have a set of three holes drilled in them, one each for the ring
Ring finger
The ring finger is the fourth digit of the human hand, and the second most ulnar finger, located between the middle finger and the little finger. It is also called digitus medicinalis, the fourth finger, digitus annularis, digitus quartus, or digitus IV in anatomy.- Etymology :According to László A...

 and middle finger
Middle finger
The middle finger or long finger is the third digit of the human hand, located between the index finger and the ring finger. It is usually the longest finger...

, and one for the thumb
Thumb
The thumb is the first digit of the hand. When a person is standing in the medical anatomical position , the thumb is the lateral-most digit...

; 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
Five-pin bowling
Five-pin bowling is a bowling variant which is played only in Canada, where most bowling alleys offer it, either alone or in combination with ten-pin bowling. It was devised around 1909 by Thomas F. Ryan in Toronto, Ontario, at his Toronto Bowling Club, in response to customers who complained that...

 ball has no finger holes and is smaller so that the bowler can hold the ball in the palm of his or her hand.
 
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