150:
room. Entropy is then depicted as a sophisticated kind of "before and after" yardstick — measuring how much energy is spread out over time as a result of a process such as heating a system, or how widely spread out the energy is after something happens in comparison with its previous state, in a process such as gas expansion or fluids mixing (at a constant temperature). The equations are explored with reference to the common experiences, with emphasis that in chemistry the energy that entropy measures as dispersing is the internal energy of molecules.
154:
dispersal for a system by the number of accessible microstates, the number of different arrangements of all its energy at the next instant. Thus, an increase in entropy means a greater number of microstates for the final state than for the initial state, and hence more possible arrangements of a system's total energy at any one instant. Here, the greater 'dispersal of the total energy of a system' means the existence of many possibilities.
239:, written for laypersons, presented a nonmathematical interpretation of what he called the "infinitely incomprehensible entropy" in simple terms, describing the Second Law of thermodynamics as "energy tends to disperse". His analogies included an imaginary intelligent being called "Boltzmann's Demon," who runs around reorganizing and dispersing energy, in order to show how the
205:'s 1852 article "On a Universal Tendency in Nature to the Dissipation of Mechanical Energy." He distinguished between two types or "stores" of mechanical energy: "statical" and "dynamical." He discussed how these two types of energy can change from one form to the other during a thermodynamic transformation. When
165:
and continually changing "distribution of the instant", and on to the idea that when the system changes, dynamic molecules will have a greater number of accessible microstates. In this approach, all everyday spontaneous physical happenings and chemical reactions are depicted as involving some type of
286:
argued that portraying entropy as "disorder" is confusing and should be abandoned. He has gone on to develop detailed resources for chemistry instructors, equating entropy increase as the spontaneous dispersal of energy, namely how much energy is spread out in a process, or how widely dispersed it
258:
In 1997, John
Wrigglesworth described spatial particle distributions as represented by distributions of energy states. According to the second law of thermodynamics, isolated systems will tend to redistribute the energy of the system into a more probable arrangement or a maximum probability energy
187:
The concept of the number of microstates makes quantitative the ill-defined qualitative concepts of 'disorder' and the 'dispersal' of matter and energy that are used widely to introduce the concept of entropy: a more 'disorderly' distribution of energy and matter corresponds to a greater number of
153:
The statistical interpretation is related to quantum mechanics in describing the way that energy is distributed (quantized) amongst molecules on specific energy levels, with all the energy of the macrostate always in only one microstate at one instant. Entropy is described as measuring the energy
141:
Increase of entropy in a thermodynamic process can be described in terms of "energy dispersal" and the "spreading of energy," while avoiding mention of "disorder" except when explaining misconceptions. All explanations of where and how energy is dispersing or spreading have been recast in terms of
149:
is introduced as "Energy spontaneously disperses from being localized to becoming spread out if it is not hindered from doing so," often in the context of common experiences such as a rock falling, a hot frying pan cooling down, iron rusting, air leaving a punctured tyre and ice melting in a warm
103:
Such descriptions have tended to be used together with commonly used terms such as disorder and randomness, 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
174:
when the two or more different substances being mixed are at the same temperature and pressure so there will be no net exchange of heat or work, the entropy increase will be due to the literal spreading out of the motional energy of each substance in the larger combined final volume. Each
123:, 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.
169:
This approach provides a good basis for understanding the conventional approach, except in very complex cases where the qualitative relation of energy dispersal to entropy change can be so inextricably obscured that it is moot. Thus in situations such as the
175:
component's energetic molecules become more separated from one another than they would be in the pure state, when in the pure state they were colliding only with identical adjacent molecules, leading to an increase in its number of accessible microstates.
267:, M.C. Gupta defined entropy as a function that measures how energy disperses when a system changes from one state to another. Other authors defining entropy in a way that embodies energy dispersal are Cecie Starr and Andrew Scott.
133:, rejecting both the 'dispersal' and the 'disorder' interpretations; instead he proposes the notion of "missing information" about microstates as considered in statistical mechanics, which he regards as commonsensical.
220:, researchers began speaking about entropy changes in terms of the mixing or "spreading" of the total energy of each constituent of a system over its particular quantized energy levels, such as by the
72:
Some educators propose that the energy dispersal idea is easier to understand than the traditional approach. The concept has been used to facilitate teaching entropy to students beginning university
108:
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.
209:
is created by any irreversible process (such as friction), or when heat is diffused by conduction, mechanical energy is dissipated, and it is impossible to restore the initial state.
100:, 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.
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183:
Variants of the energy dispersal approach have been adopted in number of undergraduate chemistry texts, mainly in the United States. One respected text states:
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energy flows from being localized or concentrated to becoming spread out to a larger space, always to a state with a greater number of microstates.
115:
grounding this notion, can lead to confusion and considerable difficulty for those beginning the subject. Even though courses emphasised
247:
relates to energy dispersion. This dispersion is transmitted via atomic vibrations and collisions. Atkins wrote: "each atom carries
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402:
263:, the total energy does not change; instead, the energy tends to disperse over the space to which it has access. In his 1999
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104:
teaching of thermodynamics. Students were being asked to grasp meanings directly contradicting their normal usage, with
844:
Carson, E. M., and Watson, J. R., (Department of
Educational and Professional Studies, King's College, London), 2002, "
461:
Carson, E. M., and Watson, J. R., (Department of
Educational and Professional Studies, King's College, London), 2002, "
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278:, published an article in 2000 showing that "entropy as disorder" was inadequate. In an article published in the 2002
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The description of entropy as the amount of "mixedupness" or "disorder," as well as the abstract nature of the
65:. Changes in entropy can be quantitatively related to the distribution or the spreading out of the energy of a
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therefore captures the aspect of dispersal: the dispersal of the entities that are carrying the energy."
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A large website by Frank L. Lambert with links to work on the energy dispersal approach to entropy.
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Benjamin Gal-Or, "Cosmology, Physics and
Philosophy", Springer-Verlag, New York, 1981, 1983, 1987
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distribution, i.e. from that of being concentrated to that of being spread out. By virtue of the
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The
Principles of Chemical Equilibrium: With Applications in Chemistry and Chemical Engineering
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blown by air as used in a lottery can then lead on to showing the possibilities of many
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Review of "Entropy and the second law: interpretation and misss-interpretationsss"
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Leff, H. S., 1996, "Thermodynamic entropy: The spreading and sharing of energy,"
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A Study of
Undergraduates' Understandings of Key Chemical Ideas in Thermodynamics
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set out what he called "the spreading and sharing of energy." Another physicist,
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has been exercised against the background of the traditional view, introduced by
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478:, Ph.D. Thesis, Department of Educational Studies, The University of York, 2001.
381:, J. Skilling, Editor, Kluwer Academic Publishers, Dordrecht, pp. 1–27, page 24.
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Using the word 'spread', an early advocate of the energy dispersal concept was
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20:
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870:
848:," University Chemistry Education - 2002 Papers, Royal Society of Chemistry.
465:," University Chemistry Education - 2002 Papers, Royal Society of Chemistry.
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189:
120:
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On a
Universal Tendency in Nature to the Dissipation of Mechanical Energy
202:
142:
energy dispersal, so as to emphasise the underlying qualitative meaning.
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thermodynamic and "configurational" ("positional") entropy in chemistry.
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Chemistry: A General
Chemistry Project of the American Chemical Society
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Undergraduate students' understandings of entropy and Gibbs Free energy
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Undergraduate students' understandings of entropy and Gibbs Free energy
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Continuous movement and molecular collisions visualised as being like
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24:
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The term "entropy" has been in use from early in the history of
51:
856:
Disorder - A Cracked Crutch For
Supporting Entropy Discussions
342:
Guggenheim, E.A. (1949), Statistical basis of thermodynamics,
16:
Interpretation of entropy as a measure of the spread of energy
427:
Disorder--A Cracked Crutch for
Supporting Entropy Discussions
235:
In 1984, the Oxford physical chemist Peter Atkins, in a book
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43:'. An early advocate of the energy dispersal conception was
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The Molecular Basis for Understanding Simple Entropy Change
206:
39:. The energy dispersal approach avoids the ambiguous term '
251:, and the spreading of the atoms spreads the energy…the
83:
377:(1989). Clearing up mysteries — the original goal, in
188:
micro-states associated with the same total energy. —
50:
In this alternative approach, entropy is a measure of
394:
Entropy and the Time Evolution of Macroscopic Systems
364:. London: Cambridge University Press. pp. 55–56.
1076:
Chemistry, The Molecular Nature of Matter and Change
990:
Brown, T. L., H. E. LeMay, and B. E. Bursten, 2006.
344:
Research: A Journal of Science and its Applications
201:The concept of 'dissipation of energy' was used in
1046:Moore, J. W., C. L. Stanistski, P. C. Jurs, 2005.
830:A Student's Approach to the Second Law and Entropy
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640:The Principles of Chemical Equilibrium, 4th Ed
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691:
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330:, Dugdale cites only Guggenheim, on page 101.
314:
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609:Proceedings of the Royal Society of Edinburg
216:. In the mid-1950s, with the development of
871:"Entropy, Its Language, and Interpretation"
622:Kinetic Theory of the Dissipation of Energy
397:. Oxford University Press. pp. 55–58.
694:Energy and Life (Modules in Life Sciences)
359:
309:
921:Texts using the energy dispersal approach
751:Biology - the Unity and Diversity of Life
563:(8th ed.). Oxford University Press.
516:
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928:Physical Chemistry for the Life Sciences
540:Notes for a "Conversation About Entropy"
474:Sozbilir, Mustafa, PhD studies: Turkey,
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1004:Ebbing, D.D., and S. D. Gammon, 2005.
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1050:, 2nd ed. Thompson Learning. 1248pp,
774:
719:
450:The Second Law of Thermodynamics (6).
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287:becomes – at a specific temperature.
84:Comparisons with traditional approach
1116:The Second Law of Thermodynamics (6)
1025:Hill, Petrucci, McCreary and Perry.
1008:, 8th ed. Houghton-Mifflin, 1200pp,
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379:Maximum Entropy and Bayesian Methods
350:, Butterworths, London, pp. 450–454.
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129:recommends abandonment of the word
13:
1092:2nd ed. Benjamin Cummings, 706pp,
994:, 10th ed. Prentice Hall, 1248pp,
976:Brady, J.E., and F. Senese, 2004.
838:
748:Starr, Cecie; Taggart, R. (1992).
47:in 1949, using the word 'spread'.
14:
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1103:
1034:Chemistry and Chemical Reactivity
978:Chemistry, Matter and Its Changes
270:In a 1996 article, the physicist
1078:, 4th ed. McGraw-Hill, 1183pp,
1067:Petrucci, Harwood, and Herring.
1048:Chemistry, The Molecular Science
1041:Thermodynamics, A Guided Inquiry
966:, 1st ed. W. H. Freeman, 820pp,
585:Entropy and Constraint of Motion
525:Entropy Is Simple, Qualitatively
322:, Taylor & Francis, London,
320:Entropy and its Physical Meaning
37:quantitative measure of disorder
1020:Essentials of General Chemistry
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671:. Scientific American Library.
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559:; de Paula, Julio (2006).
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1018:Ebbing, Gammon, and Ragsdale.
992:Chemistry: The Central Science
980:, 4th ed. John Wiley, 1256pp,
642:. Cambridge University Press.
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391:Grandy, Walter T. Jr. (2008).
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92:, and with the development of
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860:Journal of Chemical Education
589:Journal of Chemical Education
431:Journal of Chemical Education
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280:Journal of Chemical Education
1039:Moog, Spencer, and Farrell.
1032:Kotz, Treichel, and Weaver.
692:Wrigglesworth, John (1997).
147:second law of thermodynamics
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930:. Oxford University Press,
884:(12). Springer: 1744–1766.
754:. Wadsworth Publishing Co.
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261:First law of thermodynamics
245:Boltzmann's entropy formula
10:
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777:101 Key ideas in Chemistry
722:Statistical Thermodynamics
620:Thomson, William (1874). "
583:Jensen, William. (2004). "
265:Statistical Thermodynamics
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192:& de Paula (2006)
94:statistical thermodynamics
898:10.1007/s10701-007-9163-3
638:Denbigh, Kenneth (1981).
433:79: 187. Updated version
1074:Silberberg, M.S., 2006.
869:Leff, Harvey S. (2007).
779:. Teach Yourself Books.
542:: a brief discussion of
214:Edward Armand Guggenheim
90:classical thermodynamics
23:, the interpretation of
1110:welcome to entropy site
297:Introduction to entropy
163:Boltzmann distributions
1060:Olmsted and Williams,
775:Scott, Andrew (2001).
724:. New Age Publishers.
663:Atkins, Peter (1984).
628:IX: 441-44. (April 9).
318:Dugdale, J.S. (1996).
145:In this approach, the
1131:Thermodynamic entropy
113:statistical mechanics
1090:Conceptual Chemistry
1088:Suchocki, J., 2004.
720:Gupta, M.C. (1999).
67:thermodynamic system
45:Edward A. Guggenheim
890:2007FoPh...37.1744L
812:Styer D. F., 2000,
360:Denbigh K. (1981).
561:Physical Chemistry
253:Boltzmann equation
35:, of entropy as a
1069:General Chemistry
1027:General Chemistry
1006:General Chemistry
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852:Lambert, Frank L.
826:Lambert, Frank L.
536:Lambert, Frank L.
521:Lambert, Frank L.
503:Lambert, Frank L.
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423:Lambert, Frank L.
404:978-0-19-954617-6
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106:equilibrium
63:temperature
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878:Found Phys
303:References
1071:, 9th ed.
1064:, 4th ed.
1062:Chemistry
1036:, 6th ed.
1029:, 4th ed.
1022:, 2nd ed.
865:: 187-92.
854:(2002). "
603:(1852). "
448:(2011). "
425:(2002). "
222:reactants
74:chemistry
55:dispersal
1125:Category
962:, 2005.
828:(2006).
538:(2005).
523:(2005).
505:(2005).
291:See also
226:products
41:disorder
906:3485226
886:Bibcode
696:. CRC.
197:History
131:entropy
78:biology
25:entropy
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190:Atkins
59:spread
52:energy
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