Ten-pin bowling ball contacts only the 1, 3, 5 and 9 pins; for a left-hander, the 1, 2, 5 and 8 pins. In order to count, a pin must be knocked over entirely. If the pin is wobbling as the automatic pin machine picks it up (or the machine itself knocks over the pin while it is wobbling), it is still considered standing and is not scored. Also, if a pin is moved, it does not change its designation. For example, if the 10 pin were still standing and the 7 pin slid into the 8 pin position, converting this spare would
Bowling ball lighter, and without holes, so that they may be held in the palm of the bowler's hand. Most bowling alleys provide balls for patrons to use within the establishment, often referred to as "house balls." Key properties of ten-pin bowling balls include surface friction, porosity, and mass distribution, which affect the motion of the ball as it rolls. These properties are varied to control how much a ball will slide through the oily surface of a typical bowling lane, and how easily a ball will change direction when the roll is combined with rotational motion. Friction and porosity are variables