Nugget of Knowledge: The science of swing delivery

Its the IPL season and I am pretty sure you guys are enjoying the matches. However, there is always room for jello! Well, if not jello, then there is always room for some Science! 😉

Getting off the IPL mood lets look at some 2005 Ashes footage.

This was one of my childhood curiosities! Why does a cricket ball swing?

Earlier I used to think it might be because of improper weight distributions or the wind blowing during a match. But then, why only cricket balls? Why don’t we see the same thing in a tennis or cork ball? Well, the science behind it is not that obvious. 🙂

It has something to do with the roughness of the surfaces of ball which create pressure zones behind the ball in motion. This pressure is not balanced and hence causes the ball to drift on one side or the other(out swing or in-swing). It is usually seen when the ball is new and the roughness on one side of the seam is considerably less than the other. It also involves use of a cross-seam action by bowlers.

The other kind of swing called the reverse swing was mastered by Imran Khan – the former Pakistani captain. Shockingly, he could turn science on its head and make an old ball swing… that too in the opposite direction than expected!

Interesting right? 🙂

image of Balls ideal for reverse swing
Balls ideal for reverse swing

Shocking as it may seem, some experimentation can shed light and help us in understanding great deal about what a cricket ball does in its flight of 22 yards at speeds of over 130 kmph. Watch the following video for wind tunnel experiments and analysis!

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