The second law of thermodynamics works because of the statistics of very large numbers. Consider a bouncing ball: as it bounces, it dissipates heat and eventually does not bounce as high.
Friday, November 12, 2010
Fluctuations
This post is part of a series,Nonsense and the Second Law of Thermodynamics The previous post is entitled Entropy and Statistical Dynamics.
The second law of thermodynamics works because of the statistics of very large numbers. Consider a bouncing ball: as it bounces, it dissipates heat and eventually does not bounce as high.
The second law of thermodynamics works because of the statistics of very large numbers. Consider a bouncing ball: as it bounces, it dissipates heat and eventually does not bounce as high.
Saturday, November 6, 2010
Entropy and Statistical Thermodynamics
This post is part of a series, Nonsense and the Second Law of Thermodynamics. The previous post is entitled The Second Law and Swamp Coolers.
A previous post discusses the macroscopic thermodynamic definition of entropy, but there is another, statistical way of describing entropy. Consider an isolated macroscopic system of interacting molecules. Without knowing much about what is going on with the individual molecules, it is possible to measure macroscopic thermodynamic properties such as the pressure, the temperature etc.
(Figure Source)
Consider that the system is isolated; so that the total energy of the entire system of molecules is a constant. Energy is free to move from one molecule to another, and each molecule has multiple electronic, vibrational, rotational, and translational energy states that it could be in. There are many distinguishable ways that the system could be arranged to achieve the this energy.
A previous post discusses the macroscopic thermodynamic definition of entropy, but there is another, statistical way of describing entropy. Consider an isolated macroscopic system of interacting molecules. Without knowing much about what is going on with the individual molecules, it is possible to measure macroscopic thermodynamic properties such as the pressure, the temperature etc.
Consider that the system is isolated; so that the total energy of the entire system of molecules is a constant. Energy is free to move from one molecule to another, and each molecule has multiple electronic, vibrational, rotational, and translational energy states that it could be in. There are many distinguishable ways that the system could be arranged to achieve the this energy.