Tennis ball

A standard "yellow" tennis ball

A tennis ball is a ball designed for the sport of tennis, approximately 6.7 cm (2.63 in.) in diameter. Tennis balls are generally bright yellow, but in recreational play can be virtually any color. Tennis balls are covered in a fibrous fluffy felt which modifies their aerodynamic properties. Tennis balls are usually green at main sporting events.

History

Before the development of lawn tennis in the early 1870s, the sport was played as the courtly game of real tennis. In 1480, Louis XI of France forbade the filling of tennis balls with chalk, sand, sawdust, or earth, and stated that they were to be made of good leather, well-stuffed with wool. Other early tennis balls were made by Scottish craftsmen from a wool-wrapped stomach of a sheep or goat and tied with rope. Those recovered from the hammer-beam roof of Westminster Hall during a period of recent restoration were found to have been manufactured from a combination of putty and human hair, and were dated to the reign of Henry VIII.^{[citation needed]} Other versions, using materials such as animal fur, rope made from animal intestines and muscles, and pine wood, were found in Scottish castles dating back to the 16th century.^{[citation needed]} In the 18th century, ¾" strips of wool were wound tightly around a nucleus made by rolling a number of strips into a little ball.^{[citation needed]} String was then tied in many directions around the ball and a white cloth covering sewn around the ball.^{[citation needed]}

In the early 1870s lawn tennis arose in Britain through the pioneering efforts of Walter Clopton Wingfield and Harry Gem, often using Victorian lawns laid out for croquet. Wingfield marketed tennis sets, which included rubber balls imported from Germany. After Charles Goodyear invented vulcanised rubber, the Germans had been most successful in developing vulcanised air filled rubber balls. These were light and coloured grey or red with no covering. John Moyer Heathcote suggested and tried the experiment of covering the rubber ball with flannel, and by 1882 Wingfield was advertising his balls as clad in stout cloth made in Melton Mowbray.

Standardization

Tennis balls must conform to certain criteria for size, weight, deformation, and bounce criteria to be approved for regulation play. The International Tennis Federation (ITF) defines the official diameter as 65.41-68.58 mm (2.575-2.700 inches). Balls must weigh between 56.0 g and 59.4 g (1.975-2.095 ounces). Yellow and white are the only colours approved by the United States Tennis Association (USTA) and ITF, and most balls produced are fluorescent yellow (known as "optic yellow") the colour first being introduced in 1972 following research demonstrating they were more visible on (colour) television. Though tennis balls are mostly fluorescent yellow, white tennis balls were brought back to the market by Whitetennisballs.com (Roberts Brokaw LLC/Cale Quo) in 2007. Tennis balls are filled with air and are surfaced by a uniform felt- covered rubber compound. The felt delays flow separation in the boundary layer which reduces aerodynamic drag and gives the ball better flight properties.

Often the balls will have a number on them in addition to the brand name. This helps distinguish one set of balls from another of the same brand on an adjacent court.

Tennis balls begin to lose their bounce as soon as the tennis ball can is opened and can be tested to determine their bounce. A ball is tested for bounce by dropping it from a height of 100 inches (2.54 m) onto concrete; a bounce between 53 and 58 inches (1.3462 - 1.4732 m) is acceptable (if taking place at sea-level and 20°C / 68°F; high-altitude balls have different characteristics when tested at sea-level). Modern regulation tennis balls are kept under pressure (approximately two atmospheres) until initially used.

Pressureless balls

Traditional pressureless balls usually have a stiffer, woodier feel than pressurized balls and do not bounce as high as brand new pressurized balls. Unlike pressurized balls, though, they do not lose bounce over time. In fact, they get bouncier as they get lighter, due to fuzz loss. The balder they get, the more their flight, bounce, and spin responses change from what you would expect of tennis balls.

More advanced pressureless balls, such as the TreTorn MicroX, are more similar to the feel and play of pressurized balls, and last many times longer than traditional tennis balls. The TreTorn Serie+ ball is currently the official ball of the ATP Challenger series. However, the TreTorn Serie+ ball is a pressurized ball, not a pressureless.

Tretorn does not mention, if any ATP or WTA tournament ever has been played using pressureless balls. One may safely assume, that so far only pressurized balls have been used in ATP and WTA events.

Packaging

Before 1925, tennis balls were packaged in wrapped paper and paperboard boxes. In 1925, Wilson-Western Sporting Goods Company introduced cardboard tubes. In 1926, the Pennsylvania Rubber Company released a hermetically sealed pressurized metal tube that held three balls with a churchkey to open the top. Beginning in the 1980s, plastic (from recycled PET) cans with a full-top pull-tab seal and plastic lid fit three or four balls per can. Pressureless balls tend to come in nets or bags (since they do not need to be pressure-sealed).

Disposal

Each year approximately 300 million balls are produced, which contributes roughly 20,000 metric tons of waste in the form of rubber that is not easily biodegradable. Historically, tennis ball recycling has not existed and the most common use has been to cut a hole in the ball and attach the ball to the bottom of chairs in schools, nursing homes and the like to prevent scuffing or scraping the floor.^{[citation needed]} Balls from The Championships, Wimbledon are now recycled to provide field homes for the nationally threatened Eurasian harvest mouse. Tennis balls can also be rejuvenated or recycled using commercial services from reBounces. The BNP Paribas Open partnered with reBounces and FedEx Ground in 2010 to collect 15,000 tennis balls from tournament patrons from over 25 US States and six countries.

Slower balls

The ITF Play and Stay campaign aims to increase tennis participation worldwide, by improving the way starter players are introduced to the game. The campaign promotes the use of slower red, orange and optic-yellow balls,which are usually called SpongeBob balls, that give players more time and control so that they can serve, rally, and score (play the game) from the first lesson.

By using slower balls the starter players have more time and more control to make the game more fun for them at the introductory stage. The ITF Intro to Tennis Task Force recommends the red, orange, green progression for starter players. This progression focuses on a range of slower balls and court sizes to introduce the game effectively to both adults and children.

Using these slower balls will help the players to develop the most efficient technique and to be able to implement tactical situations in matches that, in most cases, could not be performed using the normal ball on a full court.

The ITF recommends that, except for exceptional players, all players aged 10 and under should use a slower red, orange or green ball in training and competition.

Other uses

Other games such as matkot, Irish handball, and two square use this ball. It is also popularly used in South Asia Australia and the West Indies for cricket due to its good bounce. In South Asia, most of street cricket is played with a modified version of Tennis balls called "cricket tennis balls". There are "Tennis-ball cricket" tournaments at school/college level. Tape ball is a variation of cricket that uses a tennis ball wrapped in electrical tape. In Canada, tennis balls are often used to play field hockey and street hockey.

Many public schools utilize old, used tennis balls as a cushion for each chair leg of the students chairs and desks.^{[citation needed]} This is a great way to prevent scuffing up floors and extends the useful life of the tennis ball.^{[citation needed]} Tennis balls can also be used to make juggling clubs.

Tennis balls are also often used as dog toys. However, the felt that covers them can wear down a dog's teeth and larger dogs can choke on tennis balls.

External links

• Vintage Tennis Balls Website and Database
• International Tennis Federation's history of the rules of the tennis ball
• ITF Grand Slam Rules:Section I:The Ball