Answer: Reduce Drag

Whether you’re a fan of the sport or not, one has to admire the sheer amount of physics going on in a game of golf. When the game is separated from the history, the dry announcers, and the lengthy time spent just admiring the lush greens of the course while waiting for the next step of the game to unfold, you’re left with all manner of interesting physics lessons to explore: the mechanics of the swing, the weight of the club head, the angle of the club face and, of course, the ball.

The physics of golf balls could be a textbook unto itself thanks to the numerous aspects of the ball’s interaction with the environment that highlight all manner of physics theories, effects, and equations. The ball has dimples, for example, not to reduce weight or any such matter but to, paradoxically, decrease drag. On cursory examination it would seem that adding hundreds of little tiny depressions on a surface would increase drag.

That much is true, actually, breaking of the surface of a previously smooth object with any sort of patterns, depressions, protrusions, or the like will, in fact, increase drag. In the case of golf balls, however, their speed and spin through the air creates what is known as the “Magnus effect” wherein a rotating body generates a lifting force similar to the effect of an airfoil. The dimples on the ball significantly increase the Magnus effect such that a dimpled ball will travel nearly twice the distance of an undimpled ball under identical conditions.

Ready for some more trivia on the matter? Here’s a curious consideration: if you could stand the look of it, you could cover your entire car with a golf-ball-like dimpled sheeting that would reduce drag and increase fuel efficiency the same way the dimpling helps a golf ball travel further and more efficiently.