75. Why do golf balls have dimples ?
For aerodynamic purposes. A smooth, solid ball won't fly nearly as straight or far as a golf ball with dimples. This is due to the thin layer of turbulent air the dimples create on a golf ball in flight. Small hollows which are present on the surface of a golf ball are called 'dimples'. The dimples on a golf ball "create a thin turbulent boundary layer of air that clings to the ball surface. This allows the smooth flow of air.