# Physics On The Golf Course

Your great drive on the golf course depends as much on physics as your skill.  The smooth balls which were used until the early 1900’s would only travel about 70 yards, even when driven well.  A good golfer today can drive dimpled golf balls over four times farther.

Why do about 400 dimples, less than a quarter of a millimetre deep, make such a difference?  It’s all to do with air drag.  The moment a golf ball leaves your club, air begins to impede its trip to the green.  A thin layer of air clings to the surface of the ball at the front, and then passes over the ball as it moves, eventually breaking away from the surface at the back of the ball.  This sets up little currents of turbulence behind the ball which slow it down.  Dimples on the surface of the ball cause the air to cling to it longer.  When the air finally breaks away from a dimpled ball, a narrower stream of turbulence is produced, which causes less drag.

In addition, since a golf ball spins backwards when you strike it, the dimples carry air over the top of the ball, where it travels faster than air underneath the ball.  This causes the air pressure above the ball to be lower than the pressure beneath it.  So the dimpled ball experiences a greater lift, keeping it flying through the air longer.

So next time you get a perfect drive onto the green, give some of the credit to the dimples on the ball, and to the laws of physics.