The Fridge Question and the Heat Death of the Universe

Housework is never completed, the chaos always lurks ready to encroach on any area left unweeded, a jungle filled with dirty pans and the roaring of giant stuffed toy animals turned savage. Terrible glass eyes.

     -- Pamela Zoline, "Heat Death of the Universe"

The question was:

You're in a perfectly insulated room.  No heat escapes.  You open the door of the fridge and leave it open. Does the room:

(a)    cool down

(b)    heat up

(c)    stay the same temperature.

Answer:

A fridge is a heat engine that pumps heat from a cold body to a warm body. This is backwards from how things happen naturally (where heat flows from a warm body out to the cooler air). To reverse entropy, we must apply external work, in the form of electricity driving a compressor and pump. If we could do this with 100% efficiency then the room would stay the same temperature. The fridge would cool at teh same rate the room heated.

But the second law states that there will always be irreversible losses that cannot do work for us. So some of the electrical energy will be lost as waste heat, instead of helping cool the fridge. The waste heat will raise the temperature in the room. So the answer is (c).

You are actually reversing entropy locally for a system (the fridge), but only by speeding it up by an even greater amount for the environment. So what that means is that every time you do work, say by picking a toy up off the ground and putting it on a shelf, you are accelerating the Heat Death of the Universe.  In case you needed another excuse not to clean up.

That man is the product of causes that had no prevision of the end they were achieving; that his origin, his growth, his hopes and fears, his loves and his beliefs, are but the outcome of accidental collocations of atoms; that no fire, no heroism, no intensity of thought and feeling, can preserve individual life beyond the grave; that all the labors of the ages, all the devotion, all the inspiration, all the noonday brightness of human genius, are destined to extinction in the vast death of the solar system, and that the whole temple of Man's achievement must inevitably be buried beneath the debris of a universe in ruins- all these things, if not quite beyond dispute, are yet so nearly certain that no philosophy which rejects them can hope to stand.  Only within the scaffolding of these truths, only on the firm foundation of unyielding dispair, can the soul's habitation henceforth be safely built.

                    --Bertrand Russel, 1903 

[consider] ... the view now held by most physicists, namely that the sun with all the planets will in time grow too cold for life, unless indeed some great body dashes into the sun and thus gives it fresh life--believing as I do that man in the distant future will be a far more perfect creature than he now is, it is an intolerable thought that he and all the other sentient beings are doomed to complete annihilation after such long-continued slow progress.

                    --Charles Darwin, 1876 

All right, a little break from thermodynamics next time. Maybe a little more on Afghanistan.