Ten-pin bowling over the Model A), all three versions are still in widespread use. The television age of the 1950s also helped to increase the popularity of ten-pin bowling, as images of the sport began to enter the homes of millions across the United States. Nationally televised programs like "Jackpot Bowling" and "Make That Spare" became popular on Friday nights from the late 1950s into the early 1960s. Following many years of debate over what constituted a professional bowler versus an amateur, Eddie Elias founded the Professional Bowlers Association (PBA) in 1958. The PBA's "Pro Bowlers Tour" became a permanent part of
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