The Cause of Swing and Reverse Swing

[peakpilgrim]

Hi

Something in Cricket that has foxed me for some time is the exact cause of;

1. Swing

2. Reverse Swing

I have been listening to the commentators on the England -Australia Ashes Series (which looks like becoming a very good series by the way) and they were saying things like: '... if we get cloud cover the ball may start to swing...'

What is it, from a scientific point of view that causes this?

Its not spin; it has something to do with the roughness on either side of the seam and the weather.

Can anyone put my ignorance to rest on this?

[Inquitus]

Basically conventional swing relies on keeping one side of the ball shiny and smooth and letting the other become rougher.

Its bowled with the seam horizontal and the air flows faster across the smooth side than the rough side inducing a curved flight.

Overhead conditions imply humidity and denser air, which accentuates the swing.

Inq

PS If you cover half a tennis ball in cellotape you can get a tennis ball to swing, its quite good fun too!

[peakpilgrim]

Originally Posted by Inquitus

Basically conventional swing relies on keeping one side of the ball shiny and smooth and letting the other become rougher.

Its bowled with the seam horizontal and the air flows faster across the smooth side than the rough side inducing a curved flight.

Overhead conditions imply humidity and denser air, which accentuates the swing.

Inq

PS If you cover half a tennis ball in cellotape you can get a tennis ball to swing, its quite good fun too!

Hi

Thanks for that Inq

Wasn't there a case a few years ago where one test team was accused of illegally using vaseline and picking at the seam to create reverse swing; how does that work?

[mike65]

Dust in the pocket used to be a favourite tactic, Mike Atherton famously took that to a level considered less than sporting 15 years back.

[D3PO]

bottlecaps were another popular tool of use to tamper with the ball. thankfully no ball tampering recently despite the allegations against pakistan in the 20/20 worldup

inq i could be wrong but smooth one side and rough the other i thought produced reverse swing and not conventional swing hense why this normally occurs when the ball is getting that bit older

[Washout]

wiki on swing

http://en.wikipedia.org/wiki/Swing_bowling

[d'Oracle]

I read an article that said there is no scientific evidence to support the effect of humidity on swing......

Cos air of higher humidty less dense than air with lower humidity.

I could get my fluid mechanics book out when i get home....

[Trojan]

Originally Posted by mike65

Dust in the pocket used to be a favourite tactic, Mike Atherton famously took that to a level considered less than sporting 15 years back.

http://www.cricinfo.com/magazine/con...ry/143193.html

[rednik]

I can still see Atherton putting his hand in his pocket, hard to believe it was 15 years ago.

[peakpilgrim]

Originally Posted by d'Oracle

I read an article that said there is no scientific evidence to support the effect of humidity on swing......

Cos air of higher humidty less dense than air with lower humidity.

I could get my fluid mechanics book out when i get home....

Thats the bit I still do not understand: why minor changes in the weather can, seemingly, cause such marked effects on swing.

[TrueDub]

Originally Posted by peakpilgrim

Thats the bit I still do not understand: why minor changes in the weather can, seemingly, cause such marked effects on swing.

Then you're in the same boat as everyone else - there are lots of theories, but nothing proven.

[mike65]

Originally Posted by rednik

I can still see Atherton putting his hand in his pocket, hard to believe it was 15 years ago.

I had exactly the same though when I went googling for back up, I though it was about 10 at most!

[booker]

Originally Posted by D3PO

bottlecaps were another popular tool of use to tamper with the ball. thankfully no ball tampering recently despite the allegations against pakistan in the 20/20 worldup

inq i could be wrong but smooth one side and rough the other i thought produced reverse swing and not conventional swing hense why this normally occurs when the ball is getting that bit older

I could be wrong but I assumed that swing and reverse swing mean the direction you are swinging the ball.

Swing is when you are bowling the ball right hand over and the ball is moving away from the right hander i.e. right to left.

Reverse is when you switch the shinny side and can move the ball into the right hander i.e. left to right.

There is also a difference between movement before it pitches, when it pitches and after it has pitched. Reverse swing usually occurs late i.e. after the ball has pitched with an older ball and is why it can be so effective for clean bowling when the right hander assumes its going to miss off stump.

[d'Oracle]

Originally Posted by booker

I could be wrong but I assumed that swing and reverse swing mean the direction you are swinging the ball.

Swing is when you are bowling the ball right hand over and the ball is moving away from the right hander i.e. right to left.

Reverse is when you switch the shinny side and can move the ball into the right hander i.e. left to right.

Nah mate.

In swing would be in to the bowler.
Out swing is away from the bowler.

Reverse swing is magical fast bowler mojo.
Basically it swings into the bowler, but then back out before it pitches.
Like an s shaped trajectory.

[Washout]

Originally Posted by d'Oracle

Nah mate.

In swing would be in to the bowler.
Out swing is away from the bowler.

Reverse swing is magical fast bowler mojo.
Basically it swings into the bowler, but then back out before it pitches.
Like an s shaped trajectory.

i always though reverse swing is where a bowler for example is shaping to bowl outswing but the ball in swings in instead

i definetly dont think that the ball takes any S Shape path.