I fell in love with astronomy at about the same age that I fell in love with cricket. There the paths diverged: quickly it became obvious to my parents and to my teachers at school that I had an aptitude for science and, almost as rapidly, they discovered that I had no aptitude at all for cricket. I loved playing cricket. I loved watching it and, when my total inability to be any use to my primary school side on the field of play became too great a handicap for me to be picked, I followed the side around the west country as its scorer.
Probably it was those happy days, many of them at weekends, which imbued me with a deep love of the statistical side of the game. Cricket is a deeply statistical game and statisticians are an essential element of it. You only have to remember how well loved Bill Frindall, Test Match scorer and statistician was: when people called him “The Bearded Wonder” it was because he inspired admiration and awe among colleagues and listeners. You don’t need to delve deep into cricket statistics though to find that they are often sadly abused numbers, not that Bill Frindall ever profaned them by calculating averages for a two match series, or taking the averages for the Sunday League seriously. No, he was way above that. To get Bill Frindall excited Brian Johnson or John Arlott, or Christopher Martin-Jenkins had to ask him how many fifties had been scored at Leeds on the first day of a Test match in June by red-headed left-handers! And, of course, he always had the answer.
For the more profane cricket fans statistics in cricket means run rates and averages. Sadly though, the latter especially are frequently thrown around like confetti by people who have no idea what they mean. When a particularly barbarous misuse of statistics is questioned, a frequent response is “you can prove anything with numbers” or, perhaps, to quote the phrase “lies, damn lies and statistics”. The fact is though that if you use them properly, aware of their limitations, you are far more likely to prove the truth than a lie. The fact that people can get aware with murder using statistics is more an indictment of the way that such numbers are rarely scrutinized properly and misuse is just accepted as a fact of life. You cannot fairly and reasonably compare the averages even of two players with simultaneous careers if they did not play in the same conditions against a similar level of opposition, let alone say, Dennis Compton with Rahul Dravid – two great players who played in different epochs, with different conditions, a different style of play and, who played, largely, in different continents!
Increasingly though statistics and numbers are impinging on other elements of the game. The speed gun is now a part of cricketing life. We all love seeing a bowler rack up speeds over 150km/h on the speed gun and largely do not question what we see. Just get a pencil and paper or, if you must, a calculator and work out what that speed means. 150km/h (93.2mph, if you prefer Imperial units) is 41.7m/s. The batsman is standing under 20 metres from the bowler and the ball will bounce perhaps 8 metres in front of him so, we would think that the batsman has perhaps 0.2s to react to the bounce of the ball. Most normal mortals will barely start to move in 0.2s, let alone be able to intercept the path of the ball with deadly accuracy with a small piece of wood. Thank heavens for physics! Otherwise batting would be even more impossible than the Gloucestershire top order makes it look. Batsman should breathe a prayer of thanks for air resistance and the rather small coefficient of restitution of a ball impacting on the pitch, which slows the ball enough that the contest between bat and speeding ball is usually reasonably even. Even so, it is a moot point, even if the ball has slowed to “only” 80km/h when it reaches the batsman, whether or not the average spectator would be able to lay bat on ball, or even start to react if he were to change places with the batsman that he is criticizing and face the bowler himself.
The ball itself is a fascinating piece of technology and one rarely appreciated by spectators or even, at times, cricketers. How often do you hear that a side has “misread the pitch”, looking for pace and bounce that just are not there? Yet no one actually points a finger at another potentially guilty party: the ball itself. You sometimes hear tennis players complain about a batch of balls feeling different, or not bouncing as high as they are used to, yet the quality standard for the bounce of a tennis ball is four times as tough as it is for a cricket ball. One new ball can bounce far higher than another in the same conditions, yet both can be acceptable according to the quality standard. Similarly, you can have a significant range of size, weight and hence density and composition of balls, even when they satisfy the stringent standards of the ICC. As a cricket ball is a natural product, it is inevitable that no two balls can never ever behave in exactly the same way.
You can find fascinating physics wherever you look on a cricket pitch. Not just the ball. A cricket bat has fascinating similarities to a musical instrument in its behaviour and a fine bat maker will tune a bat as well as Stradivarius ever tuned a violin. The science of ballistics, with a little help from mechanics and aerodynamics, determines whether that lofted shot from Kevin Pietersen is going to cross the boundary rope safely and be cheered as a big six, or drop conveniently into the hands of the fielder waiting for it just inside the field of play. And, bowling is simply applied fluid dynamics. A bowler who is “making the ball talk”, is simply applying fluid dynamics more successful than the batsman is applying mechanics to the process of hitting it. A successful bowler will apply laminar and turbulent flow as well as any laboratory physicist can. Even spin bowlers will sometimes demonstrate a thorough grounding in this field, although they will also express a scholarly interest in the Magnus effect and the coefficient of friction of leather on a compressed earth/grass composite.
Of course, probably the most controversial application of physics to the modern game of cricket is in adjudicating umpiring decisions. So much heat gets expended on umpiring aids such as Hawkeye, Snicko and HotSpot and of the iniquities of slow motion replays of critical incidents. In some ways cricket is the last of the luddites. Tennis has used Hawkeye for years without its accuracy being called into question and the precursor of Hawkeye was around the tennis courts thirty years ago, yet put Hawkeye on a cricket pitch and suddenly everyone wants to second-guess it. Forget the fact that Hawkeye showed at the World Cup that umpires get far more marginal decisions right than they do wrong, you cast doubt on it and, often, the human umpire too who is doing this damndest to get things right when over the course of a day there may be an average of one appeal per over. You either accept human frailty and the fact that even the best umpire will make the occasional mistake, or you accept that a computer can predict the trajectory of the ball, warts and all. Even when the physical principals are as simple as HotSpot – friction between bat and ball heats the bat, which then radiates black body radiation at around ten microns, which is detected by a sensitive thermal imaging camera – you can find incidents that can cast doubt on its veracity and validity. There will always be some uncertainly in marginal cases and no technology that humans can invent will ever be able to eliminate that uncertainty completely.
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