What are tennis balls made of

What are tennis balls made of?

From the pressurized rubber core to the felt cover, man-made materials make up most of the parts of a tennis ball. In some cases, recycled PET plastics are used to make the felt that covers tennis balls. The International Tennis Foundation sets rules that determine the standard size, composition and coloring of official tennis balls.

A close up of a tennis ball on the court. (Image: aodaodaod / iStock / Getty Images)

Modern composition

Today's tennis balls consist of a hollow, two-part rubber shell that is filled with pressurized gas. The rubber shell is covered with felt made of nylon or wool. According to the ITF, tennis balls should be between 2 1/2 and 2 5/8 inches in diameter and weigh between 2 and 2 1/16 oz. The felt used to cover tennis balls intended for the official game is light yellow.

production

Tennis ball manufacturers shape rubber into two shapes that are squeezed together to form the core of a ball. To achieve a reasonable level of bounce, tennis ball manufacturers inject a certain amount of compressed air into the center of each rubber core. Manufacturers polish the sealed, pressurized rubber balls and cover them with glue. Machines cut long pieces of light yellow felt into two shapes that are wrapped around each tennis ball to form a cover. Ball makers heat up the finished tennis balls so the adhesive forms a seal that holds the two pieces of fabric together.

history

Tennis was first played in the 1870s, and the first tennis balls were made from leather or cloth and filled with rags or horsehair. Rubber tennis balls were developed in India and quickly became the standard for lawn tennis games. Players added flannel coatings to rubber tennis balls to increase their durability. In order to increase the hitting ability of the tennis ball, the ballmakers began to pressurize the center of the rubber core with compressed air. Tennis balls were originally black or white, but the ITF introduced yellow tennis balls in the 1970s because the bright colors made the balls easier to see for TV viewers.

Bounce

The ITF states that tennis balls must bounce between 53 and 58 inches after being dropped onto a concrete floor from a height of 100 inches. In order to achieve this precise jump height, tennis ball makers add a certain amount of air to the core of tennis balls. In general, tennis balls are loaded with a pressure of 12 pounds per square inch.