WEBVTT - How Golf Ball Dimples Work

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<v Speaker 1>Get smarter in sixty seconds with brain stuff from how Stuffworks,

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<v Speaker 1>dot Com, Hi and Marshall Brain. If you've ever looked

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<v Speaker 1>at a golf ball, you know that it has dimples,

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<v Speaker 1>but why is that? The reason why golf balls have

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<v Speaker 1>dimples is a story of natural selection. Originally golf balls

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<v Speaker 1>were smooth, but golfers noticed that older balls that were

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<v Speaker 1>beat up with knicks, cuts, and slices in the cover

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<v Speaker 1>seemed to fly further. Golfers, being golfers, naturally gravitate toward

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<v Speaker 1>anything that gives them an advantage on the golf course,

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<v Speaker 1>so old beat up balls became standard issue. At some point,

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<v Speaker 1>an aerodynamsis looked at this problem and realized that the

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<v Speaker 1>knicks and cuts were acting as turbulators. They induced turbulence

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<v Speaker 1>in the layer of air next to the ball, known

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<v Speaker 1>as the boundary layer. In some situations, a turbulent boundary

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<v Speaker 1>layer reduces drag. A sphere happens to be one shape

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<v Speaker 1>that gets a big boost from turbulators. The dimples that

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<v Speaker 1>we see today are simply organized optimized turbulators on the

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<v Speaker 1>surface of the ball. If you want to get a

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<v Speaker 1>little deeper than the aerodynamics, there are two types of

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<v Speaker 1>flow around an object, there's laminar flow and turbulent flow.

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<v Speaker 1>Laminar flow is good. It has less drag, but it's

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<v Speaker 1>also prone to a problem called separation. One separation occurs,

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<v Speaker 1>you get a lot of drag because of eddies that

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<v Speaker 1>form in the gap. Turbulent flow has more drag initially,

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<v Speaker 1>but it's also got better adhesion. It therefore is less

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<v Speaker 1>prone to separation. If the shape of an object is

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<v Speaker 1>such that separation occurs easily, as in a sphere, it's

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<v Speaker 1>better to turbulate the boundary layer at a slight cost

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<v Speaker 1>of increased drag in order to increase adhesion and reduce eddies,

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<v Speaker 1>which means significant reduction in drag. Dimples on golf balls

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<v Speaker 1>turbulate the boundary layer and help the all fly further.

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<v Speaker 1>A golf ball with dimples can fly twice as far

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<v Speaker 1>as a smooth sphere of the same size and weight.

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<v Speaker 1>Do you have any ideas or suggestions for this podcast?

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