I have no idea if this was really submitted as a test question anywhere - but it's still funny, so here it is. Thanks to frequest reader & commenter Lili for submitting this one:
Thermodynamics (contributed by Lilith)
The following is an actual question given on a University of Washington chemistry mid-term. The answer by one student was so "profound" that the professor shared it with colleagues, via the Internet, which is, of course, 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 when it expands and heats 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 at which souls are moving into Hell and the rate at which 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. Most 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 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 proportionately as souls are added.
This gives two possibilities: 1) 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.
2) 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 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 an affair with her, then #2 above cannot be true, and thus I am sure that Hell is exothermic and will not freeze over."
THIS STUDENT RECEIVED THE ONLY "A."
Excellent find Joe. Linking to this pronto.
My goodness! It appears you read everything, Joe. I am impressed. Tell me your secret of time management—please. How do you work and keep up WoC too? : -)
Perhaps we should ask those on WoC who are proficient in thermodynamics whether they could expound on exothermy vs. endothermy.
Lili
Great story. It's been making the rounds on the net, WWW and email, for two or three years, minimum. Dislike the role of wet blanket and am certain that the opportunity for those who haven't seen it will make the post worthwhile.
Quite a bit longer than that Steve... I remember this from back when I was at nerd camp, oh, 6 years ago.
Still cracks me up. :)
Gees, Steve. I had the decency to not mention to the person who sent it to me that I had seen it years ago and several times since then.
Clearly, it's still funny.
Can one link pictures to this site or post graphics?
This one has been going around the net for years. Not sure if it's a myth or what. Never bothered to check it out on one of the urban legend sites.
Still a great story.
Well, I was a chemistry major (briefly) in college, so here's what I remember about the thermo question.
Particular processes can be described as either exothermic or endothermic. The process in question doesn't have to be a chemical reaction, like burning a piece of wood; it can also be a state change, like a piece of ice melting (the ice remains H2O throughout, but it changes from a solid state to a liquid state).
An exothermic process is one that releases heat. Burning practically anything is an exothermic reaction. An endothermic process is the reverse--heat is absorbed from the surroundings. Ice melting into liquid water is endothermic; so is salt dissolving in water.
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The article posted above should have said Ideal Gas Law, not Boyle's Law, since Boyle's Law has nothing to do with heat. Boyle's Law states that if you have a given quantity of gas, at a constant temperature, the pressure multiplied by the volume equals a constant.
Here's Boyle's Law in plain English. Let's say you have a box full of air. One of the walls of the box can be moved in and out to make it larger or smaller, but the edges are sealed, so no air leaks in or out (like a piston in an engine). Therefore, by moving the wall, you can directly control the volume of the box. Boyle's Law says that as long as 1) there are no leaks, and 2) the temperature does not change, making the box bigger will decrease the air pressure inside and making the box smaller will increase the pressure.
Boyle's Law is a special case of the Ideal Gas Law, which states that the product of the pressure (P) and volume (V) equals the product of the number of moles of gas (n), the Gas Law constant ®, and the temperature (T) in Kelvin (PV=nRT). Specifically, Boyle's Law holds n and T constant, to make the right side of the equation all constant.
In the Hell analysis, you would need the more general Ideal Gas Law, since you need to find how T varies over time. If T goes up over time, Hell is exothermic. If T goes down over time, Hell is endothermic.
(Next, we cover whether a reaction is spontaneous, based on the change in free energy (delta G), which is equal to the change in enthalpy (delta H) minus the product of the temperature (T) in Kelvin and the change in entropy (delta S)...ah, thermodynamics....)
The story was considered an "oldie but goodie" when I learned it ... thirty two years ago.
Snopes says this goes back to as far as 1997.
As vbc said, it's really an oldie. I first saw it on UseNet back in 1994 or so. And it wasn't new to me then. But it's still funny. Some things never change...
Sam,
The real fun comes in when you combine that with heat transfer and fluid flow. Which may be of some assistance re: the pumping question and Ms. Teresa.
Then you apply all that to a typical piston pump with a fair nod to length of stroke, piston seal, volumetric efficiency, valve timing, compression ratios, and if you deal in steam - relief valves.
I could see where the engineer in question might be getting into an over pressure condition with no relief from Ms. Teresa.
If the plant in question is nuclear then a SCRAM followed by massive amounts of high pressure cooling water to prevent a melt down accident are surely called for. What you want to do is prevent the uncontrolled release of dangerous fluids and gases.
============================================Of course all this is much fun. But not near so much fun as male and female mating connectors. i.e. electrical engineers mate more often.
I have this great picture of the difference between men and women illustrated with a machine/device.
For women the device as dozens of knobs, pulls and switches.
For men, merely two: "On" and "Off"
The joke above clearly supports the "simplicity" theory. Even scientists respond to the carrot. ;-)
This goes back much farther than 1997 (Snopes).
I was a physical chemistry (of macromolecules) major at Yale 1965-1969. I struggled with a lot of thermodynamics. This chestnut was already overly familiar, and thus bred the usual contempt, way back then.
Sorry.
Jamie Irons