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Version 0 Version 1
Weatherwatch: What gives a cricket ball its swing? Weatherwatch: What gives a cricket ball its swing?
(3 months later)
In first class cricket matches the fielding side industriously polishes one side of the ball on their trousers, and there have been recent accusations about whether some have also been surreptitiously roughing up the other.In first class cricket matches the fielding side industriously polishes one side of the ball on their trousers, and there have been recent accusations about whether some have also been surreptitiously roughing up the other.
All this polishing is to allow air to flow more readily over the smooth surface on one side of the ball than on the rough surface on the other. The idea, if the bowler can keep the seam straight, is to make the ball swing in the air and so give the bowlers a decided advantage over the batsmen. But none of this works without the right weather conditions.All this polishing is to allow air to flow more readily over the smooth surface on one side of the ball than on the rough surface on the other. The idea, if the bowler can keep the seam straight, is to make the ball swing in the air and so give the bowlers a decided advantage over the batsmen. But none of this works without the right weather conditions.
The great mystery is why cricket balls swing in the air much more on some days than others. An example is the Test match in 1999 against New Zealand when 21 wickets fell on the second day of the match, 2 July, and the next day a normally unsuccessful batsman was able to get 99 not out.The great mystery is why cricket balls swing in the air much more on some days than others. An example is the Test match in 1999 against New Zealand when 21 wickets fell on the second day of the match, 2 July, and the next day a normally unsuccessful batsman was able to get 99 not out.
The weather, when the wickets of both sides tumbled, was heavy cloud with humid air and the next was bright and breezy.The weather, when the wickets of both sides tumbled, was heavy cloud with humid air and the next was bright and breezy.
Folklore has it that the humidity is the key to the swing but wind tunnel tests show that this has little effect. It appears to be the stillness of the air as the ball whizzes through it that allows the swing effect to build up as the ball nears the bat.Folklore has it that the humidity is the key to the swing but wind tunnel tests show that this has little effect. It appears to be the stillness of the air as the ball whizzes through it that allows the swing effect to build up as the ball nears the bat.
A breeze or air turbulence caused by the sun warming the pitch destroys the effect.A breeze or air turbulence caused by the sun warming the pitch destroys the effect.
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