21 June 2010

The Demon of Maxwell

South African author Joan De La Haye offers Demon Friday. Surprisingly, it's each Friday and it involves a demon from one grimoire or another. She also greets us as 'freaky darlings', similar to Vampira. Top class!

This is my own take on Demon Friday, except it's not always on Fridays and it doesn't feature real demons or pictures of real demons. Sorry.

These are all my posts on demons:

  1. The demon of Laplace, regarding probability.

  2. The demon of Maxwell, regarding thermodynamics.

  3. The demon of Descartes, designed to invoke skepticism.

  4. The demon of Morton, designed to make one aware of confirmation bias.




Maxwell's demon is a thought experiment proposed by James Clerk Maxwell. Maxwell invented the demon to attempt to show that the second law of thermodynamics is only a statistical anomaly and not a rigid, unbreakable law. Like the law that prevents Ozzy Osbourne from taking a slash on the Alamo cenotaph.

The Second Law of Thermodynamics Revisited


Remember that the second law of thermodynamics states that the entropy of the universe tends to a maximum, or stated differently: you can not win.

Megan Fox naked from the waist down

Megan Fox. Like a young Angelina Jolie with gimp feet.

Thus, the second law of thermodynamics states that the universe is in a state of universal decay. That's right, Lady Gaga and Megan Fox are not going to be sex symbols for all eternity. An almost famous Spinal Tap quote has it that:

“Well, Nigel and Dave are two extremes, like fire and ice. I see my role in the band is to be somewhere in between... like lukewarm water.”

Which illustrates the second law of thermodynamics perfectly. The second law requires that there is an energy flow between bodies until an equilibrium is reached. This means that fire, which is in a more chaotic state than ice, would cause ice to take on a more chaotic state. By the same token, ice would cause fire to take on a slightly less chaotic state, until the luke warm water somewhere in between becomes apparent.

Maxwell's Demon and the Luke Warm Water Somewhere in Between


Suggest that we have a container with blue coloured ice water. We pour a cup of red coloured scolding water into this container. According to the second law of thermodynamics, we ought to end up with luke warm purple water, but not if Maxwell's demon has his way.

Maxwell's demon is a hypothetical creature that can discern between the molecules of the ice water and those of the boiling water by sensing its energy levels. Maxwell claims that his demon would thus be able to separate the blue ice water molecules from the red scolding water molecules. His demon would do so by means of a trap door.

This means that, if such a demon existed, the second law of thermodynamics would be broken, as it is hypothetically possible to move from a currently more chaotic purple state to a previously less chaotic red and blue state. If entropy is symmetrically reversible, it means that there are ways to overcome the problem that the universe tends to maximum entropy. It also means that Megan Fox and Lady Gaga can stay hot for ever. Great...

More importantly, it means that perpetual motion is possible. Which would be nice considering that loads of our oil has been spilt in the Gulf of Mexico by BP. I'm not sure if Maxwell's demon would be a convincing argument for mortgage refinancing, but it's worth a shot.

No comments:

Creative Commons License