Tennis Balls

Tennis balls today are made of a hollow rubber and have a felt covering. They were originally white in color and were used widely, but over the years have been changed to a yellow, which allows for more visibility for both the players and officials that cover the game. The chair umpire and line people need to differentiate the ball from the white colored court lines, which are used to judge it the ball bounced inside or outside the line. Each ball must meet certain criteria before it can be used at a competitive level. The weight, size, deformation and amount of bounce have to be approved.

The official diameter is between 2.575 - 2.7 inches and the balls must weigh between 1.975 and 2.095 ounces. The International Tennis Federation and the United States Tennis Association only allow yellow and white balls. Yellow balls were only introduced in 1972 following studies that proved they were more visible. The hollow balls are filled with a specific amount of air and that helps with the bounce and flight of the ball making it have less of an aerodynamic drag.

The bounce in the ball begins to reduce as soon as they are taken out of the pressured cans they are distributed in. They are only used for a certain number of games in each competition. Testing of the balls is done by dropping them from a height of 100 inches and a bounce of between 53 and 58 inches is required to be used in competitive matches.