Subject: Why are some golf clubs curved?

Why are some golf clubs curved?
Well- between the physics teacher across the hall and myself 
we are unable to explain why the surface of woods (golf clubs)
have a curved surface. The primary reason for this is that we 
don't have a clue. I've heard general explanations, such as
"it gives the ball a different spin to keep it in the fairway,
etc". In specific terms of physics we are unable to come up with 
an answer. Please help.  We're looking pretty bad in front of our
students on this one.

Thanks - Al Wagner 

Re:Why are some golf clubs curved?