The "Why" of a Golf Ball's Flight 



The corrugations on a golf ball are not meant to beautify 

 the ball; they determine its maximum carrying distance 



The secret of a golf ball's motion is to 

 be found in the churning of the air by the 

 corrugations on the surface. A blanket 

 of air packs against it and diverts it 



At right: A pitcher is able to "curve" the 

 ball by making the ball chum the air. In 

 a vacuum a body might be imagined 

 to continue in a perfectly straight line 



WE are told in school that when a ball 

 is thrown into the air it generally 

 travels in only one kind of vertical 

 path, the so-called parabolic, while its path 

 as seen from above never diverts from 

 a straight line. But that this is not 

 exactly true during baseball games and 

 during golf contests, may be confirmed by 

 any "fan." And when a long "brassie" 

 drive is made, the golf ball may even rise 

 upward during some part of its flight; so 

 that its path can hardly be called para- 

 bolic. The schools would be exactly 

 right in their statements if the effects 

 of the air upon the spinning ball were 

 not considered. But the fact is that 

 if it were not for the influence of the air, a 

 baseball could never be made to bewilder a 

 batter nor a golf ball be made to "take" an 

 obstructing "hazard." 



When a pitcher desires the path of a base- 

 ball to curve in a certain direction, he gives 

 the ball as it leaves his hand a rapid spin in 

 this same horizontal direction. The effects 

 of the air upon the whirling ball are exactly 

 those that would occur on a more pro- 

 nounced scale if the ball were thrown 

 through a long strip of watei. The lacing 



5A5E5ALL 



on the ball churns the air in which it spins 

 and carries the air around with it. But the 

 side which is turning in the same direction 

 about the ball's center as the direction the 

 ball itself is to turn, will be "packing" the 

 air against its side, just as it would be 

 doing with the water. Thus the air will be 

 slightly compressed on that side, and as the 

 ball skims along on the blanket of air so 

 formed, it naturally will be pushed away 

 from it and be made to curve in its path. 

 The corrugated marking on a golf ball 

 causes exactly the same phenomenon to 

 take place. Here, however, the ball is 

 rotated around a horizontal axis instead of a 

 vertical axis as in the previous case. The 

 golf stick hits the ball on its under side so 

 that this side rotates upward in front of the 

 ball as it spins through the air. In this way 

 the air packs the blanket this time under- 

 neath the ball, and so tends to divert the 

 ball upward. As a consequence, the ball, 

 instead of continuously being forced down- 

 ward is also slightly pushed in an upward 

 direction by the blanket of air underneath. 

 The golf ball is thus able to stay up in the 

 air longer and the length of its flight is pro- 

 portionally increased. 



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A golf ball need not even travel in a parabola. By hitting it properly it can be made to rise 

 up at a higher angle than that which it was initially given, and so lengthen its flight. The 

 Stick should hit the ball on its imder side so that side will rotate upward in front of the ball 



186 



