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By Ben Coxworth
Professor Derek Leinweber has been studying soccer balls. He’s interested in the physics behind them, and is particularly intrigued by the design of the official ball for the 2010 FIFA World Cup South Africa, the Adidas Jabulani. He thinks it will behave in a much different fashion than the previous World Cup ball, throwing goalkeepers for a loop - all because of the ridges on its skin.
Governing body FIFA has strict regulations on the size and weight of balls, but none regarding their outside surface. This means that the skin is where Adidas has been concentrating its efforts at making better soccer balls. The Jabulani’s “grip’n’groove” ridges are designed both for improved grip, and for better control. Leinweber, who heads the School of Chemistry and Physics at the University of Adelaide in Australia, believes that they will create turbulence around the ball, resulting in longer flights. Given that it is also a relatively small, heavy ball (within FIFA guidelines), it should make for faster, harder play.
Adidas’ previous World Cup ball, the Teamgeist, had a freakishly smooth skin. This apparently caused it to bend more than a conventional ball, and to drop more rapidly at the end of its trajectory. Ironically, the Jabulani should also prove to be a bender, perhaps more so than anything that has come before it.