World Cup 2014: How the 'Magnus Effect' lets players 'bend it like Beckham'

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Have you ever wondered how some soccer players get such a lovely curve on the ball when they kick it?

It has to do with a phenomenon known as the Magnus Effect, says UC Riverside physics professor Robert Clare.

Related: World Cup 2014: Where to watch you country's team

Gustav Magnus was a 19th century German physicist who identified the effect when he was studying how cannonballs travel through air.

"It’s basically when a ball is spinning there is a force on one side of the ball which is bigger than on the other side and that causes it to curve,” says Clare.

He says imagine a spinning ball that’s moving forward through a stream of air.

One side will be spinning with the air steam and the other side will be spinning against it.

Clare says the side spinning against the stream creates a drag, causing a pile up of air that results in higher pressure. The side spinning with the stream pulls air with it, creating a lower air pressure effect.

It’s this unequal air pressure dynamic that makes the ball not just fly forward, but curve, he says.

“Soccer players, the really good ones work very hard on being able to kick the ball both very hard so they can get it going fast, but also with a lot of spin so you get that curve ball.”

You can see the Magnus effect at play in this epic kick by Roberto Carlos.


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