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The description of entropy as energy dispersal provides an introductory method of teaching the thermodynamic concept of entropy. In physics and physical chemistry, entropy has commonly been defined as a scalar measure of the disorder of a thermodynamic system. This newer approach sets out a variant approach to entropy, namely as a measure of energy ''dispersal'' or ''distribution'' at a specific temperature. Under this approach, changes in entropy can be quantitatively related to the distribution or the spreading out of the energy of a thermodynamic system, divided by its temperature. The energy dispersal approach to teaching entropy was developed to facilitate teaching entropy to students beginning university chemistry and biology. This new approach also avoids ambiguous terms such as disorder and chaos, which have multiple everyday meanings. ==Problem: entropy as disorder is hard to teach== The term "entropy" has been in use from early in the history of classical thermodynamics, and with the development of statistical thermodynamics and quantum theory, entropy changes have been described in terms of the mixing or "spreading" of the total energy of each constituent of a system over its particular quantized energy levels. Such descriptions have tended to be used together with commonly used terms such as disorder and chaos which are ambiguous, and whose everyday meaning is the opposite of what they are intended to mean in thermodynamics. Not only does this situation cause confusion, but it also hampers the teaching of thermodynamics. Students were being asked to grasp meanings directly contradicting their normal usage, with equilibrium being equated to "perfect internal disorder" and the mixing of milk in coffee from apparent chaos to uniformity being described as a transition from an ordered state into a disordered state.〔Microsoft Encarta 2006. © 1993–2005 Microsoft Corporation. All rights reserved.〕 The description of entropy as the amount of "mixedupness" or "disorder," as well as the abstract nature of the statistical mechanics grounding this notion, can lead to confusion and considerable difficulty for those beginning the subject.〔〔Frank L. Lambert, "(The Second Law of Thermodynamics (6). )"〕 Even though courses emphasised microstates and energy levels, most students could not get beyond simplistic notions of randomness or disorder. Many of those who learned by practising calculations did not understand well the intrinsic meanings of equations, and there was a need for qualitative explanations of thermodynamic relationships.〔Carson, E. M., and Watson, J. R., (Department of Educational and Professional Studies, Kings College, London), 2002, "(Undergraduate students' understandings of entropy and Gibbs Free energy, )" University Chemistry Education - 2002 Papers, Royal Society of Chemistry.〕〔Sozbilir, Mustafa, PhD studies: Turkey, ''A Study of Undergraduates' Understandings of Key Chemical Ideas in Thermodynamics'', Ph.D. Thesis, Department of Educational Studies, The University of York, 2001.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Entropy (energy dispersal)」の詳細全文を読む スポンサード リンク
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