NME 3 - 1982
A Thermodynamical Analysis of the Committee
- A Case for the Post of Maxwell's Demon - Stephen Barnett
(page 18/19)
Non-Muddled Explanation


A Thermodynamical Analysis of the Committee
- A Case for the Post of Maxwell's Demon.

by Stephen Barnett

Danger - all those students taking Physics or allied disciplines are advised that reading this article could seriously damage their exam results.

Consider a thermally isolated committee room, into which we place six committee members and six cups (polystyrene) of lukewarm "Lyons instant tea" (the significance of the tea will become apparent later).

For those not yet initiated into the wonders of thermodynamics, there are two laws:

  1. Change in energy = Change in heat + Work done
    dE = dQ + dW
  2. No process is possible whose sole result is the complete conversion of heat into work.

From these two laws my first argument can be plainly seen; the input of heat dQ is six cups of lukewarm tea, (not a vast amount of energy) most of which is needed to do work (2 says not all of it may be used).

As arguments can get quite heated, dE is large. Clearly, far from work being done by the commmittee, som external force must be doing work to hold it together (the Maxwell's Demon?)

To those of you who dislike the above sketchy, qualitative, classical argument, I now present a more detailed statistical mechanical treatment:

cup - by S. Barnett

Consider an individual committee member. His digestive system can be considered as a heat bath containing the heat from the tea. The brain of our commmittee member can most easily be modelled as a two level system (energies o and e) in contact with the heat bath. Let the tea have energy content E. We now have two possibilities, either the brain is in energy state o (energy in heat bath E) or it is in energy state e (energy in heat bath E-e). Clearly as there are so many microstates associated with E, and so many fewwer with E-e, that the probability of having the brain in state e (without the help of M's D to fiddle the energy) is minute.

"So what?" I hear you cry. Well, the energy is the capacity to do work, and if the brain is in the zero energy mode then it can't do any.

Our last hope seems to be quantum mechanics and good old Heisenberg - dE dT ≈ h. We have calculated the work to be done to be about zero, but if our uncertainty is large enough, maybe we are O.K. If a committee meeting lasts about two hours, then the uncertainty in the amount of energy available to produce work is dE = h/dt = 10-34/602 x 2 = 10-38 J. Not enough to say 2001, let alone put it on!

My only conclusion is that one (or more) member of the committee is performing the role of Maxwell's Demon, and is fiddling the entropy. This is a very difficult and time consuming job, and I therefore propose that the special position of Maxwell's Demon be added to the commmittee.