Maxwell's Demon - Not a Perpetual Motion Machine

Maxwell's Demon - Not a Perpetual Motion Machine

Entropy is not a difficult concept to just take at face value, but it is a difficult topic to gain a good understanding of. To do this some background must be given such as the first and second law of thermodynamics. The second law of thermodynamics states that any event that occurs spontaneously must result in an increase in the randomness of lhe syslem. This means that as an ice cube melts the water molecules that it is composed of will progress toward a less ordered arrangement. The leaves that fall from the trees do nol arrange themselves in a pile on the ground because the second law of thermodynamics is against it. Entropy is a concept that most high school chemistry and physics students enjoy learning about because the now have an excuse for having a messy room, they are fighting nature.

For a better understanding of the theory of entropy it helps to understand the first law of thermodynamics, energy can neither be created nor destroyed, it may only change forms. In other words the energy of the universe is constant. For the universe (the ultimate system) to give up energy to increase ordered is not a likely event. Therefore ,for a system, a persons room for example, to become more ordered, energy must be put into the system, cleaning the room. Everything in the universe is governed by entropy through the Gibbs free energy equation which states; the heat content of the system, minus the temperature of the system times the entropy, or randomness will dictate whether the event will be spontaneous. Entropy is actually centered around the probability of an event occurring. The greater the statistical probability of a particular event occurring, the greater the entropy. A good example of this is an experiment with a new deck of playing cards. When the cards are first unwrapped they are arranged in numerical order and according to suit, if the cards are thrown into the air and allowed to fall to the floor. When they are swept up and restacked, we will almost certainly find that the cards have become disordered. We would expect this disordering to occur because there are millions of ways for the cards to become disordered and only one way for them to come together again in their original sequence.

Another result of the second law of thermodynamics is that spontaneous changes are always accompanied by a dispersal of energy into a more disordered form.