Is the art of spin bowling all in the cross-wind? Ahead of the Ashes, England and Australia could learn from these two physicists

Equations that govern the trajectory of a
spinning ball as it moves through the air have been published

How can a spin bowler improve his googly or doosra, his leg break or slider? Cricketers may well spend years honing their techniques to improve the flight, pitch and bounce of the ball but a pair of Australian physicists has discovered that by just waiting a few moments for a cross-wind to pick up could prove crucial to taking wickets.

Brothers Garry and Ian Robinson publish equations today that govern the trajectory of a spinning ball as it moves through the air in a swirling wind. England and Australia’s Ashes squads may want to pay attention to the paper as they seek to gain an advantage in the series, which begins at Trent Bridge, Nottingham, next Wednesday.

The brothers reveal that the presence of a cross-wind from either side of the cricket pitch can cause the spinning ball to either slightly ‘hold up’ or ‘dip’, depending on which direction the wind comes from and which way the ball is spinning. This will significantly change the point at which the ball pitches on the wicket leaving a batsman bamboozled.

The Robinsons showed that when a 14 km/h cross-wind interacts with the spinning ball, the point at which it hits the ground can change by around 14 cm, which they believe may be enough to further deceive an opponent.

Other factors they took into account were the speed of the ball, gravity, the drag force caused by air resistance and the Magnus or ‘lift’ force, while at the same time incorporating the important effect of wind.

The Magnus force is a common effect, particularly in ball sports, when the spin of a ball causes it to curve away from its set path. Wrist spinners like Shane Warne especially utilise the effect to get the ball spinning as fast as possible. The effect on a topspin delivery makes the ball dip faster in the air and bounce further away from the batsman than he originally thought it would. The extra dip also means that the ball will hit the ground at a steeper angle and therefore bounce higher.

Isaac Newton first correctly observed and inferred the Magnus effect when watching tennis players at Trinity College, Cambridge. The effect itself is named after German physicist Heinrich Gustav Magnus who described it in an 1852 paper while investigating how to make German artillery more accurate.

Footballers such as David Beckham also utilise the effect when curling the ball around defenders or a wall of players from a set piece.

Garry Robinson said: “Our results show that the effects on a spinning ball are not purely due to the wind holding the ball up, since a reversal of wind direction can cause the ball to dip instead. These trajectory changes are due to the combination of the wind and the spin of the ball.

“The effects of spin in the presence of a cross-wind, and how to fully exploit it, may or may not be completely appreciated by spin bowlers. Either way, we have provided a mathematical model for the situation, although the model of course awaits detailed comparison with observations.”

Once the equations were constructed, they were solved using a computer software program: the solutions were then used to create illustrative examples for cricket.
The Robinsons, from the University of New South Wales and the University of Melbourne, also showed that a spinning cricket ball tends to ‘drift’ in the latter stages of its flight as it descends, moving further to the off-side for an off-spinning delivery, which Graeme Swann specialises, and moving further towards the leg-side for a leg-spinning delivery. Their research is published in the Institute of Physics’s Physica Scripta journal.
Garry added: “We hope that this work can be used to cast new light on the motion of a spinning spherical object, particularly as applied to cricket, whilst also stirring the interests of students studying differential equations.”

PROMOTED VIDEO
Have you tried new the Independent Digital Edition apps?
Life and Style
tech
News
The 67P/CG comet as seen from the Philae lander
scienceThe most important scientific breakthroughs of 2014
Arts and Entertainment
Ian McKellen as Gandalf in The Hobbit: The Battle Of The Five Armies
film
Arts and Entertainment
Sarah Koenig, creator of popular podcast Serial, which is to be broadcast by the BBC
tvReview: The secret to the programme's success is that it allows its audience to play detective
News
Ruby Wax has previously written about her mental health problems in her book Sane New World
people
Caption competition
Caption competition
Latest stories from i100
Daily Quiz
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

Career Services

Day In a Page

Homeless Veterans appeal: 'You look for someone who's an inspiration and try to be like them'

Homeless Veterans appeal

In 2010, Sgt Gary Jamieson stepped on an IED in Afghanistan and lost his legs and an arm. He reveals what, and who, helped him to make a remarkable recovery
Could cannabis oil reverse the effects of cancer?

Could cannabis oil reverse effects of cancer?

As a film following six patients receiving the controversial treatment is released, Kate Hilpern uncovers a very slippery issue
The Interview movie review: You can't see Seth Rogen and James Franco's Kim Jong Un assassination film, but you can read about it here

The Interview movie review

You can't see Seth Rogen and James Franco's Kim Jong Un assassination film, but you can read about it here
Serial mania has propelled podcasts into the cultural mainstream

How podcasts became mainstream

People have consumed gripping armchair investigation Serial with a relish typically reserved for box-set binges
Jesus Christ has become an unlikely pin-up for hipster marketing companies

Jesus Christ has become an unlikely pin-up

Kevin Lee Light, aka "Jesus", is the newest client of creative agency Mother while rival agency Anomaly has launched Sexy Jesus, depicting the Messiah in a series of Athena-style poses
Rosetta space mission voted most important scientific breakthrough of 2014

A memorable year for science – if not for mice

The most important scientific breakthroughs of 2014
Christmas cocktails to make you merry: From eggnog to Brown Betty and Rum Bumpo

Christmas cocktails to make you merry

Mulled wine is an essential seasonal treat. But now drinkers are rediscovering other traditional festive tipples. Angela Clutton raises a glass to Christmas cocktails
5 best activity trackers

Fitness technology: 5 best activity trackers

Up the ante in your regimen and change the habits of a lifetime with this wearable tech
Paul Scholes column: It's a little-known fact, but I have played one of the seven dwarves

Paul Scholes column

It's a little-known fact, but I have played one of the seven dwarves
Fifa's travelling circus once again steals limelight from real stars

Fifa's travelling circus once again steals limelight from real stars

Club World Cup kicked into the long grass by the continued farce surrounding Blatter, Garcia, Russia and Qatar
Frank Warren column: 2014 – boxing is back and winning new fans

Frank Warren: Boxing is back and winning new fans

2014 proves it's now one of sport's biggest hitters again
Jeb Bush vs Hillary Clinton: The power dynamics of the two first families

Jeb Bush vs Hillary Clinton

Karen Tumulty explores the power dynamics of the two first families
Stockholm is rivalling Silicon Valley with a hotbed of technology start-ups

Stockholm is rivalling Silicon Valley

The Swedish capital is home to two of the most popular video games in the world, as well as thousands of technology start-ups worth hundreds of millions of pounds – and it's all happened since 2009
Did Japanese workers really get their symbols mixed up and display Santa on a crucifix?

Crucified Santa: Urban myth refuses to die

The story goes that Japanese store workers created a life-size effigy of a smiling "Father Kurisumasu" attached to a facsimile of Our Lord's final instrument of torture
Jennifer Saunders and Kate Moss join David Walliams on set for TV adaptation of The Boy in the Dress

The Boy in the Dress: On set with the stars

Walliams' story about a boy who goes to school in a dress will be shown this Christmas