A true story.

 A thermodynamics professor had written a take-home exam for his graduate 
students. It had one question:

"Is hell exothermic or endothermic? Support your answer with a proof."

Most of the students wrote proofs of their beliefs using Boyle's Law or 
some variant.

One student, however wrote the following: First, we postulate that if 
souls exist, then they must have some mass. If they do, then a mole of 
souls can also have a mass. So, at what rate are souls moving into hell 
and at what rate are souls leaving? I think that we can safely assume 
that once a soul gets to hell, it will not leave. Therefore, no souls are 
leaving. As for souls entering hell, lets look at the different religions 
that exist in the world today. Some of these religions state that if you 
are not a member of their religion, you will go to hell. Since there is 
more than one of these religions and people do not belong to more than 
one religion, we can project that all people and all souls go to hell. 
With birth and death rates as they are, we can expect the number of souls 
in hell to increase exponentially. Now, we look at the rate of change in 
volume in hell. Boyle's Law states that in order for the temperature and 
pressure in hell to stay the same, the ratio of the mass of souls and 
volume needs to stay constant. So, if hell is expanding at a slower rate 
than the rate at which souls enter hell, then the temperature and 
pressure in hell will increase until all hell breaks loose. Of course, if 
hell is expanding at a rate faster than the increase of souls in hell, 
than the temperature and pressure will drop until hell freezes over.

It was not revealed what grade the student got.