At 09:49 PM 7/20/2011, Karl Wolz wrote:
>Golf balls are dimpled because, with the tremedous rate of backspin
>developed by the angled club face, they actually fly, with the dimples

They'd produce lift just as well without the dimples.  But the
dimples generate turbulence which creates more drag *but* helps keep
the laminar airflow from separating on the trailing edge of the ball
and producing big eddies, giving a net reduction in drag.

The lift is significant, by the way.  I did a Science Fair project in
high school that involved a cardboard cylinder spun by a flexible
shaft from an Erector Set motor.  Blow air across it from a window
fan and like the little angels it would rise up, rise up, rise up
high.  [That's for you, Ed...and others with ears to hear.]

The little angled afterthoughts you see stuck on to big aircraft
wings are turbulence generators, and you can buy them for cars as well.

There's a great article here:
http://www.aerospaceweb.org/question/aerodynamics/q0215.shtml

Yours,
David