Entropy
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| - | A [[measure]] of the [[amount]] of [[energy]] in a [[physical]] [[system]] which cannot be used to do [[mechanical work]]. | + | In 1930, [[Gilbert Newton Lewis]] gave a simple explanation: ''"Gain in '''entropy''' always means loss of information, and nothing more."'' |
| - | A measure of the [[disorder]] [[present]] in a system (now becoming obsolete in chemistry | + | == Thermodynamics and Information == |
| + | The term '''entropy''' is used in thermodynamics, information theory and mathematics. In classical thermodynamics entropy is a [[measure]] of the [[amount]] of [[energy]] in a [[physical]] [[system]] which cannot be used to do [[mechanical work]]. Here, the dimension for entopy is [[energy]]<nowiki>[</nowiki>[[Joule]]<nowiki>]</nowiki> devided by temperature<nowiki>[</nowiki>[[Kelvin]]<nowiki>]</nowiki>. | ||
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| + | However, if a measuring system is used which uses thermal energy instead of temperature, then entropy is a dimensionless factor. In order to compute in such a measuring system the share of a ressource (e.g. energy or information) which is not-available to any determined or determinable operation, the measure of quantity of that ressource (e.g. using the units <nowiki>[</nowiki>Joule<nowiki>]</nowiki> or the pseudo unit <nowiki>[</nowiki>bit<nowiki>]</nowiki>) is multiplied by that factor. | ||
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| + | == Disorder == | ||
| + | Explaining entropy using the term "[[disorder]]" often leads to confusion, because disorder itself can be understood in too many different ways. | ||
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| + | == Links == | ||
| + | *Mark Dow: ''[http://lcni.uoregon.edu/~mark/Stat_mech/thermodynamic_entropy_and_information.html The connection between thermodynamic entropy and information]'' | ||
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| + | == References == | ||
| + | *[http://www.ariehbennaim.com/books/index.html Ben-Naim, Arieh] (2008): ''A Farewell to Entropy: Statistical Thermodynamics Based on Information'' | ||
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Revision as of 18:06, 27 February 2010
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In 1930, Gilbert Newton Lewis gave a simple explanation: "Gain in entropy always means loss of information, and nothing more."
Contents |
Thermodynamics and Information
The term entropy is used in thermodynamics, information theory and mathematics. In classical thermodynamics entropy is a measure of the amount of energy in a physical system which cannot be used to do mechanical work. Here, the dimension for entopy is energy[Joule] devided by temperature[Kelvin].
However, if a measuring system is used which uses thermal energy instead of temperature, then entropy is a dimensionless factor. In order to compute in such a measuring system the share of a ressource (e.g. energy or information) which is not-available to any determined or determinable operation, the measure of quantity of that ressource (e.g. using the units [Joule] or the pseudo unit [bit]) is multiplied by that factor.
Disorder
Explaining entropy using the term "disorder" often leads to confusion, because disorder itself can be understood in too many different ways.
Links
References
- Ben-Naim, Arieh (2008): A Farewell to Entropy: Statistical Thermodynamics Based on Information
