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

Inquitus wrote: »

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....:D

Trojan

mike65 wrote: »

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/content/story/143193.html

rednik

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

peakpilgrim

d'Oracle wrote: »

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....:D

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

TrueDub

peakpilgrim wrote: »

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

rednik wrote: »

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!

khn10ur3bogzpa

D3PO wrote: »

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

Bianca Square Rap wrote: »

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

d'Oracle wrote: »

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.

khn10ur3bogzpa

d'Oracle wrote: »

Nah mate.

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

What does in to the bowler mean? Also I didnt mention in swing or out swing....just so you know

d'Oracle

Bianca Square Rap wrote: »

What does in to the bowler mean? Also I didnt mention in swing or out swing....just so you know

My mistake, I meant Batsman.:D

And I can see that you didnt mention in swing.
But you described it.
In swing to a RH batsman = Left to right
Out Swing to the RH Batsman = Right to Left.

I suppose (as Jimmy Anderson proves continually) you can swing it both ways without using reverse swing.

Washout wrote: »

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

Ok, I was exaggerating a bit as a sort of joke.
(Note at this point there is no actual such thing as Magic.)

Reverse Swing is (usually) generated with an old ball where the rough side has deteriorated so much that it starts to behave like a smooth side.
Thus an inswinger delivery, (ball with seam angled at the legside or a RHB and smooth side facing off or a RHB) will swing towards the off side, away from the batsman. This occurs later in the delivery than with conventional swing.

When both conventional swing and reverse swing occur you can get an S-shaped trajectory.

Here is a perfect example. (See slowmo)
Out-swing out of his hand, then late reverse swing coming back in. Peach of a delivery.

TrueDub

d'Oracle wrote: »

Reverse Swing is (usually) generated with an old ball where the rough side has deteriorated so much that it starts to behave like a smooth side.
Thus an inswinger delivery, (ball with seam angled at the legside or a RHB and smooth side facing off or a RHB) will swing towards the off side, away from the batsman. This occurs later in the delivery than with conventional swing.

This is the case - reverse swing comes when the ball does the opposite of what you'd expect.