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
Ten-pin bowling it is damaging the integrity of the sport. Before 1970, nearly all bowling balls had a hard rubber surface. As the coatings applied to wood lanes changed from softer lacquer to a harder urethane in the early 1970s, the first polyester balls became widely available. Subsequent changes since the early 1980s — particularly with urethane surfaced and later "reactive" resin or composite ("particle") surfaced bowling balls—have been altering the physics of how the ball rolls and strikes the pins. Coupled with synthetic lane surfaces and advanced oiling machines presenting the opportunity to lay out lane oil patterns that make targeting