• Question: Hi.Why does a football sometimes not go were you want it to?

    Asked by booto67 to Ryan, James, Evan on 20 Jun 2011.
    • Photo: Ryan Ladd

      Ryan Ladd answered on 18 Jun 2011:

      With practice I think you can get more and more control over where a football goes when you kick it. Though there will always be unpredictable things which can make the ball roll or bounce the wrong way. Perhaps the wind blows at a bad time or the grass is wet or there’s a small bump on the pitch, all kinds of things could change where the ball goes.

    • Photo: Evan Keane

      Evan Keane answered on 20 Jun 2011:

      This is a great question. The movement of a football can be very complicated. Did you ever wonder how to bend it like Beckham? The trick is to make a “Magnus force”. What is this? Well if you kick a ball down the middle it will just go straight (of course wind and things could change that too). But if you kick not at the centre it will go forward AND SPIN. You have to make it spin. Practice that. If it spins as it travels through the air a whirlpool is created around the ball and it experiences an extra force. Depending on which way you make it spin, the force will go in different directions and you can curve the ball, or make it dip very quickly.

      If you hit it below centre it will have “back spin” and the force makes it go down with “a dip”. This is what footballers try to do when they shoot over a wall of players but want the ball to come down after it’s just gone over the players. If you spin it sideways you get a curve to the side. Professional footballers master this with practice. There effect is also used in baseball when the pitcher throws a “curve ball” and in tennis too. If you practice a lot you might be able to do this …

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