Coming to grips with a `sticky wicket'

I awoke one morning recently to the extraordinary news that the West Indies, or "Windies", as they seem to call them nowadays…

I awoke one morning recently to the extraordinary news that the West Indies, or "Windies", as they seem to call them nowadays, had played cricket against Bangladesh in Dublin. Cricket, it seems, discovered a gap in the virtually continuous sequence of world cups of every kind, and found it irresistible. Even more shocking, they seem to have decided that the various elevens should wear different coloured tracksuits, rather than the whites traditionally de rigueur. O tempora! O mores!

Be that as it may, the state of the atmosphere at any given time may well have a bearing on how the tale unfolds. Temperature and humidity, it seems, partly control the amount of "swing" experienced by a cricket ball - the extent to which it veers off course confusingly in its trajectory. By constant but selective polishing, a bowler can arrange that one side of a ball is rather smoother than the other; then as it flies through the air, the smooth surface of the ball experiences less frictional drag than does the rough side, causing a veer in the direction of the rough.

The extent of this veer, apparently, is related to the weather - presumably because of resulting variations in the density of the air around the ball. On a bright sunny day very little swing will be expected, but in dull, overcast and "heavy" conditions, massive swing may make the ball difficult for a bowler to control, and equally difficult for the batsman to hit well. A good bowler, it seems, takes the effect of the weather on the likely swing into account when planning his trajectory.

Then there is the proverbial "sticky wicket". A bowler often delivers a ball with a pronounced spin in the forward direction. When such a ball hits the ground, there is friction between the surface of the ball itself and the ground. This friction opposes and reduces the spin: some of the rotational kinetic energy lost in this way goes into heating the surface of contact with the ground, but a part is converted into additional translational kinetic energy - and this makes the ball move faster after the bounce.

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A wicket is "sticky", it seems, when it has dried out rapidly in sunshine after a period of rain. A spinning ball delivered in these circumstances for some reason grips the ground more effectively than in other conditions: friction is maximised, and the ball proceeds towards the wicket with greatly enhanced velocity and in a way that is very difficult for a batsman to anticipate.