It has the special property that it is always perpendicular to the spin axis of the ball and its forward direction. This is called the Magnus force after its discoverer, the German physicist HG Magnus. And this is when the kicker needs to produce the right kind of spin.Ī ball in flight experiences three important forces: gravity (the ball’s weight) aerodynamic drag caused by air flowing across its surface and a special force experienced only when the ball spins. Getting the ball over the wall is not especially a problem, but bringing the modern ball down sufficiently quickly to commit the goal keeper into making a save is another matter, unless a special kicking technique is used. Here the objective is to beat the defensive wall, to get the ball “up and down” to use the jargon of football’s television pundits. Enhanced speed is highly desirable in penalty kicks, but not for that other important football set piece: the direct free kick. But what the subsequent technology has produced is a ball with much reduced aerodynamic drag, which means it flies faster, and stays in the air longer. Problems with the German Teamgeist ball, such as its erratic behaviour in flight, have now largely been eliminated in its successors. The panel configuration of a ball influences its speed and flight through the air. The ball being used at Euro 2016 in France, the Beau Jeu, is essentially a derivative of the Brazuca with identical panel design, so for the moment six appears to be the ideal number of panels. Then in South Africa 2010 the Jabulani ball featured only eight, and in Brazil 2014 there were just six on the Brazuca. In the World Cup in Germany that year, the Teamgeist ball had only 14 panels. For nearly 40 years the ball’s panel pattern followed the classic hexagon-pentagon format with 32 panels, but in 2006 the design changed radically. But few have affected the game as profoundly as technological changes to the aerodynamic properties of the ball. Football has seen many innovations during its 150-year history.
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