I was emailed the following by Reynir Stefánsson, who says: "I have seen a few versions of this on the net, but so far none better than the one enclosed below".
The university mentioned varies widely around the Web -- for example, some sites quote Texas A&M, others quote McGill., naming the student, identifying the course as "Momentum, Heat and Mass Transfer II" at the University of Oklahoma School of Chemical Engineering, and the examiner as Dr. Schambaugh, allegedly famous for asking exam questions such as "why do airplanes fly". There is indeed such a person as Dr. Schambaugh at that institution, but when Reynir emailed him for confirmation, his reply was: "The course number and title are correct, and I have asked why airplanes fly. But I never asked a question about hell." (All of which suggests the perpetrator may be one of the students on that course...)
[Dec 2011] John Jensen emailed me to say that Snopes has the answer; they attribute it to Paul Darwin Foote.
The following is an actual question given on a University of Washington engineering mid term. The answer was so profound that the Professor shared it with colleagues, which is why we now have the pleasure of enjoying it as well.
Bonus Question: Is Hell exothermic (gives off heat) or Endothermic (absorbs heat)?
Most of the students wrote proofs of their beliefs using Boyle's Law, (gas cools off when it expands and heats up when it is compressed) or some variant. One student, however, wrote the following:
"First, we need to know how the mass of Hell is changing in time. So we need to know the rate that souls are moving into Hell and the rate they are 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 how many souls are entering Hell, let's 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 are more than one of these religions and since people do not belong to more than one religion, we can project that 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 of the volume in Hell because Boyle's Law states that in order for the temperature and pressure in Hell to stay the same, the volume of Hell has to expand as souls are added. This gives two possibilities:
- 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, then the temperature and pressure will drop until Hell freezes over.
So which is it? If we accept the postulate given to me by Teresa Banyan during my Freshman year, "...that it will be a cold day in Hell before I sleep with you." and take into account the fact that I still have not succeeded in having sexual relations with her, then, #2 cannot be true, and thus I am sure that Hell is exothermic and will not freeze."
This student received the only A.