I have a student doing a project on squash balls: these are rather soft
rubber balls which don't bounce very well, but get more and more elastic as
their temperature is raised through being slammed around the court.
He's measuring the coefft of restitution at different temperatures, and
getting something like a linear graph. The problem is to produce an
explanation. He needs to be pointed in a fruitful direction, but I find
myself stuck. It seems clear that it's the air inside the ball that causes
this behaviour, rather than the rubber, but how to relate this to the
dissipation that occurs during a bounce...?