QUESTION:
We know that if you send a styrofoam cup to the bottom of the ocean it 
shrinks in size because of the weight of the water pressing down from 
above. What would happen to a styrofoam cup sent into the Earth's
atmosphere or into the Martian atmosphere, which is less dense than 
Earth's?

ANSWER from Bob Haberle on May 7, 1997:
My guess is that nothing much will happen to the cup on Mars. Yes, 
the atmosphere is less dense (by about a factor of 70), but I don't 
think this will cause the cup to expand much (it should expand a 
little) or even come apart. In fact, I'll bet that even if you put the
cup into outer space where the density is virtually zero, that the cup 
would still remian intact. The molecular binding forces are strong
enough (my guess) to keep it together.