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November 19, 2004
Entropy and Chaos
The other night, my husband, Tom, and I were talking about physics. He recalled enjoying physics--until he ran across a professor with whom he had to argue vociferously. This professor claimed that entropy was something precise and measurable; Tom understood entropy to be uncertainty. I recall entropy from my chemistry studies--and as I remember it--it was the "fudge factor," a number used to balance the thermodynamic equations--not something that was measurable in its own right. This got me thinking about whether the oft-used word "chaos" might be the new word for "entropy."
A quick Google search resulted in an interesting article Entropy and Chaos vs. Dispersion of Energy by a self-professed free-lance thermo engineer. The opening paragraph reads:
The "Great Confusion about Entropy" lies in the perception that entropy is "real", in the sense that it is a thermodynamic property (or dimension) of a system, often perceived as the dispersion of energy, instead of it being a measure for chaos, or disorder. However, no engineer needs to know a thing about entropy to calculate and design a thermodynamic machine, such as a compressor, a turbine, etc. In consequence, if entropy can be ignored by the engineer, without disabling him/her to make a functioning thermo machine, entropy can not be a physical property, the way internal energy is. It then simply is a quantitative notion and, as we will see in the following, of the amount of disorder (chaos).
Tom is an engineer and has designed and built many a system--concrete and virutal--without having taken entropy into account. I, once upon a time a chemist, knew entropy as the "fudge factor" to balance equations. And there are still professors claim that entropy has nothing to do with chaos and everything to do with the dispersion of energy. A reminder to me that in order to understand something, we create mental models. I wonder what it would be like if we could understand a thing without having to create an internal model....
Posted by Kerry at November 19, 2004 11:59 PM