From wool-wrapped sheep stomachs to the yellow spheres we know today.
Ever wondered about the origins of these fluffy fluorescent spheres that we love to thwack to ’n’ fro across strung-up fishing nets? Behold the back story of these bouncy balls…
Tennis has its origins in 12th century France after the aristocracy – presumably weary with all the crusading, conquests and chivalry – noticed how much fun young clergymen were having slapping round things about their stone monasteries and wanted in on the action. The game eventually evolved into a kingly diversion now termed Real Tennis (yup, sorry to inform you that means this plebian pursuit called the Australian Open is actually fake tennis, and didn’t catch on until the 1870s).
Around 1480, the evil French despot Louis XI decreed that tennis balls could no longer be stuffed with sand, chalk, sawdust or dirt, and instead, were to be constructed of quality leather stuffed with wool (look, the dude had a well-earned rep for sinister plots and intrigues, but he was also a bit of a tennis buff). And sure enough, as you do when your supreme monarch has a penchant for beheadings and uncomfortably spiky dungeon implements, the umpires of the day saw the wisdom in allowing the trend to catch on. Soon other balls began to be made using wool-wrapped sheep stomachs bound tightly with rope (now you know why your dog instinctively loves them so much). And given ol’ Louis was a cranky sort, no doubt a few of his enemies’ internal organs found their way inside his playthings so he could belt them about for fun, too.
However, by the 16th century and Henry VIII’s reign (yes, the English started copying the French, can you believe it?), new ball designs were made from a mixture of human hair and putty, while later on in the 1700s, the balls were put together using a cork nucleus around which small strips of wool were wound, followed by lots of string and eventually sewn over with a white cloth. This style remains utilised in Real Tennis to this day.
Fast forward to the mid-to-late 19th century. Lawn tennis became hip amongstBritain’s gentry, helped along by Charles Goodyear’s invention and eventual patent in 1844 of vulcanised rubber (no, nothing to do with Leonard “Spock” Nimoy). By then, balls were red or grey and uncovered, until a Pommy barrister called John Moyer Heathcore (one of the founding rule-makers of lawn tennis) suggested covering the rubber balls with flannel.
By the 1920s, tennis balls become pressurised and covered with felt to optimise their aerodynamics. As a result, so they didn’t lose their bounce, they had to be stored in hermetically sealed cans or tubes. Indeed, bounciness is tested – the International Tennis Federation has strict codes that any ball dropped from a height of 254 cm onto concrete must bounce back between 135 cm and 147 cm, and must be tested under a uniform temperature of 20°C, 60 per cent humidity and atmospheric pressure of 102 kPa. Likewise, a tennis ball’s diameter must be between 65.41 mm and 68.58 mm and weigh between 56 g and 59.4 g. Lastly, since 1972 and the advent of colour TV, ‘optic yellow’ became the standard colour for all tennis balls so as to increase their visibility for spectators. Prior to that, all balls had been white.
As for why you like to take a fresh tennis ball and rub it against your cheek (admit it, we all do!), well, scientists are still trying to work that weird phenomenon out.