# Cricket ball swing-How to explain it

by tariq5
Tags: ball, cricket, explain, swinghow
 P: 11 Dear fellows since a long I have been puzzled by the cricket ball swing and reverse swing phenomenon. For fast bowlers when they(ball) throw ball(pitching with straight elbow vertically or near vertical movement of the arm) the ball swings may be towards the batsman(in swing) or away from the batsman(out swing). It is an Axiom among cricketers and cricket scientists world over that phenomenon is due to friction of air to one side of the ball(it is worth mentioning that most of the bowlers rub one side of the ball to keep the shine on it and keep the other side rough, that how the cheaters sometimes use bottle caps or others thing to rough one side).The older ball swing much more than the new. I am a medical doc but I have seen people swinging the soccer ball, ping pong ball and tennis ball and all the balls without keeping into the consideration the rough and smooth theory. I am, therefore, reluctant to accept this friction of air theory(may be it play slight part) but major element is how you throw the ball. All bowlers use two fingers on the seam or the ball(index and middle) and thumb on the other side of the .It is when one pushes the index or middle finger determines the swing of the ball(or some use angle of the arm during delivering the ball ). Is momentum of body play some role or in fact that is rough shine theory. Can some body please explain it?
 Emeritus Sci Advisor PF Gold P: 11,154 With a cricket ball, it does have to do with friction. The relative flow velocity is greater on the smooth side and lower on the rough side. This difference in flow velocity provides a sideward "lift", following the Bernoulli principle. With soccer or ping-pong, the difference in flow velocity is achieved by means of spinning the ball. However, with a cricket ball, a fast bowler does not spin the ball. He holds the seam essentially vertically and delivers the ball in that orientation. Sometimes, however, you can see a small amount of swing in the ball even when bowled by a spinner. This is due to the rotational effect, rather than the friction effect.
 P: 11 Thanks Gokul The actual problems now arise: 1-The brand new ball do swing(even first ball). 2-Isn't it against the "Bernoulli's Principle " The ball swings towards the rough side! 3-The same ball same techniques but with twist of fingers and or fingers the swing goes to wrong side(the reverse swing). 4-Not always the seam is vertical but most of the case it is much tilted. 5-If the air friction is too much it should cause the spin on the ball. 6-An irregular stone does swing. 7-Does spin causes deviation in the air or it stabilizes the path?After hitting the ground it does cause deviation. My opinion is there is more force to one side of the ball cause it to swing. Is that possible?
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## Cricket ball swing-How to explain it

In that way Gokul, Why should Pakistanis do so much research in developing the reverse swing? you will get it if you reverse the position of the rough side and the smooth side. Please explain this in detail.