Get smarter in sixty seconds with brain stuff from how Stuffworks, dot Com, Hi and Marshall Brain. If you've ever looked at a golf ball, you know that it has dimples, but why is that? The reason why golf balls have dimples is a story of natural selection. Originally golf balls were smooth, but golfers noticed that older balls that were beat up with knicks, cuts, and slices in the cover
seemed to fly further. Golfers, being golfers, naturally gravitate toward anything that gives them an advantage on the golf course, so old beat up balls became standard issue. At some point, an aerodynamsis looked at this problem and realized that the knicks and cuts were acting as turbulators. They induced turbulence in the layer of air next to the ball, known as the boundary layer. In some situations, a turbulent boundary layer reduces drag. A sphere happens to be one shape
that gets a big boost from turbulators. The dimples that we see today are simply organized optimized turbulators on the surface of the ball. If you want to get a little deeper than the aerodynamics, there are two types of flow around an object, there's laminar flow and turbulent flow. Laminar flow is good. It has less drag, but it's also prone to a problem called separation. One separation occurs, you get a lot of drag because of eddies that
form in the gap. Turbulent flow has more drag initially, but it's also got better adhesion. It therefore is less prone to separation. If the shape of an object is such that separation occurs easily, as in a sphere, it's better to turbulate the boundary layer at a slight cost of increased drag in order to increase adhesion and reduce eddies, which means significant reduction in drag. Dimples on golf balls turbulate the boundary layer and help the all fly further.
A golf ball with dimples can fly twice as far as a smooth sphere of the same size and weight. Do you have any ideas or suggestions for this podcast? If so, please send me an email at podcast at how stuff works dot com. For more on this and thousands of other topics, go to how stuff works dot com.