Speaker 1: Get smarter in sixty seconds with brain stuff from how Stuffworks,
Speaker 1: dot Com, Hi and Marshall Brain. If you've ever looked
Speaker 1: at a golf ball, you know that it has dimples,
Speaker 1: but why is that? The reason why golf balls have
Speaker 1: dimples is a story of natural selection. Originally golf balls
Speaker 1: were smooth, but golfers noticed that older balls that were
Speaker 1: beat up with knicks, cuts, and slices in the cover
Speaker 1: seemed to fly further. Golfers, being golfers, naturally gravitate toward
Speaker 1: anything that gives them an advantage on the golf course,
Speaker 1: so old beat up balls became standard issue. At some point,
Speaker 1: an aerodynamsis looked at this problem and realized that the
Speaker 1: knicks and cuts were acting as turbulators. They induced turbulence
Speaker 1: in the layer of air next to the ball, known
Speaker 1: as the boundary layer. In some situations, a turbulent boundary
Speaker 1: layer reduces drag. A sphere happens to be one shape
Speaker 1: that gets a big boost from turbulators. The dimples that
Speaker 1: we see today are simply organized optimized turbulators on the
Speaker 1: surface of the ball. If you want to get a
Speaker 1: little deeper than the aerodynamics, there are two types of
Speaker 1: flow around an object, there's laminar flow and turbulent flow.
Speaker 1: Laminar flow is good. It has less drag, but it's
Speaker 1: also prone to a problem called separation. One separation occurs,
Speaker 1: you get a lot of drag because of eddies that
Speaker 1: form in the gap. Turbulent flow has more drag initially,
Speaker 1: but it's also got better adhesion. It therefore is less
Speaker 1: prone to separation. If the shape of an object is
Speaker 1: such that separation occurs easily, as in a sphere, it's
Speaker 1: better to turbulate the boundary layer at a slight cost
Speaker 1: of increased drag in order to increase adhesion and reduce eddies,
Speaker 1: which means significant reduction in drag. Dimples on golf balls
Speaker 1: turbulate the boundary layer and help the all fly further.
Speaker 1: A golf ball with dimples can fly twice as far
Speaker 1: as a smooth sphere of the same size and weight.
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