Golf balls have dimples because a rough surface helps the ball travel farther through air.

The longer version

A smooth sphere moving through air leaves a wide wake of low pressure behind it, which drags the ball backwards. Dimples trip the thin layer of air clinging to the surface into turbulence, and that churned layer stays attached farther around the back of the ball before separating. The wake shrinks, pressure drag falls, and the ball carries much farther than a polished one would.

Players noticed the effect long before it was explained: scratched and dented balls from the nineteenth century flew better than new smooth ones, so wear was copied on purpose. Dimple depth, count and pattern are now tuned to balance carry against lift, since spin matters too. The same trick of roughening a surface appears in other ball sports where seams or fuzz change flight.

Where this entry sits

Facts here look at the rules, equipment and odd histories behind familiar sports and games, from balls and rackets to cards, boards and playing fields. Expect small details about scoring quirks, stadium design and the long story of the Olympic Games. The full list sits on the Sports and Games page, where every entry is listed in order.