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Thermodynamics Quotes (27 quotes)
Thermo-dynamics Quotes, Thermo-dynamic Quotes

A perfect thermo-dynamic engine is such that, whatever amount of mechanical effect it can derive from a certain thermal agency; if an equal amount be spent in working it backwards, an equal reverse thermal effect will be produced.
'Thomson on Carnot’s Motive Power of Heat' (appended to 'Réflexions sur la puissance motrice du feu' (1824) translated by R.H. Thurston) in Reflections on the Motive Power of Fire, and on Machines Fitted to Develop that Power (1890), 139.
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A theory is the more impressive the greater the simplicity of its premises is, the more different kinds of things it relates, and the more extended is its area of applicability. Therefore the deep impression which classical thermodynamics made upon me. It is the only physical theory of universal content concerning which I am convinced that within the framework of the applicability of its basic concepts, it will never be overthrown.
Autobiographical Notes (1946), 33. Quoted in Gerald Holton and Yehuda Elkana, Albert Einstein: Historical and Cultural Perspectives (1997), 227.
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Classical thermodynamics ... is the only physical theory of universal content which I am convinced ... will never be overthrown.
Quoted in Albert Einstein and Stephen Hawking (ed.), A Stubbornly Persistent Illusion (2007), 353.
Science quotes on:  |  Theory (582)

For if there is any truth in the dynamical theory of gases the different molecules in a gas at uniform temperature are moving with very different velocities. Put such a gas into a vessel with two compartments [A and B] and make a small hole in the wall about the right size to let one molecule through. Provide a lid or stopper for this hole and appoint a doorkeeper, very intelligent and exceedingly quick, with microscopic eyes but still an essentially finite being.
Whenever he sees a molecule of great velocity coming against the door from A into B he is to let it through, but if the molecule happens to be going slow he is to keep the door shut. He is also to let slow molecules pass from B to A but not fast ones ... In this way the temperature of B may be raised and that of A lowered without any expenditure of work, but only by the intelligent action of a mere guiding agent (like a pointsman on a railway with perfectly acting switches who should send the express along one line and the goods along another).
I do not see why even intelligence might not be dispensed with and the thing be made self-acting.
Moral The 2nd law of Thermodynamics has the same degree of truth as the statement that if you throw a tumblerful of water into the sea you cannot get the same tumblerful of water out again.
Letter to John William Strutt (6 Dec 1870). In P. M. Hannan (ed.), The Scientific Letters and Papers of James Clerk Maxwell (1995), Vol. 2, 582-3.
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For the second law [of thermodynamics], I will burn at the stake.
Comment made to H. Montgomery during his time at Harwell. In D. Shoenberg's obituary of H. London, Biographical Memoirs of Fellows of the Royal Society (1971), 17, 442.
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Heat can never pass from a colder to a warmer body without some other change, connected therewith, occurring at the same time.
'On a Modified Form of the Second Fundamental Theorem in the Mechanical Theory of Heat', Philosophical Magazine, 1856, 12, 86.
Science quotes on:  |  Heat (90)

Heat energy of uniform temperature [is] the ultimate fate of all energy. The power of sunlight and coal, electric power, water power, winds and tides do the work of the world, and in the end all unite to hasten the merry molecular dance.
Matter and Energy (1911), 140.
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How did Biot arrive at the partial differential equation? [the heat conduction equation] . . . Perhaps Laplace gave Biot the equation and left him to sink or swim for a few years in trying to derive it. That would have been merely an instance of the way great mathematicians since the very beginnings of mathematical research have effortlessly maintained their superiority over ordinary mortals.
The Tragicomical History of Thermodynamics, 1822-1854 (1980), 51.
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In a sense cosmology contains all subjects because it is the story of everything, including biology, psychology and human history. In that single sense it can be said to contain an explanation also of time's arrow. But this is not what is meant by those who advocate the cosmological explanation of irreversibility. They imply that in some way the time arrow of cosmology imposes its sense on the thermodynamic arrow. I wish to disagree with this view. The explanation assumes that the universe is expanding. While this is current orthodoxy, there is no certainty about it. The red-shifts might be due to quite different causes. For example, when light passes through the expanding clouds of gas it will be red-shifted. A large number of such clouds might one day be invoked to explain these red shifts. It seems an odd procedure to attempt to 'explain' everyday occurrences, such as the diffusion of milk into coffee, by means of theories of the universe which are themselves less firmly established than the phenomena to be explained. Most people believe in explaining one set of things in terms of others about which they are more certain, and the explanation of normal irreversible phenomena in terms of the cosmological expansion is not in this category.
'Thermodynamics, Cosmology) and the Physical Constants', in J. T. Fraser (ed.), The Study of Time III (1973), 117-8.
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In all cases where work is produced by heat, a quantity of heat proportional to the work done is expended; and inversely, by the expenditure of a like quantity of work, the same amount of heat may be produced.
'On the Moving Force of Heat, and the Laws regarding the Nature of Heat itself which are deducible therefrom', Philosophical Magazine, 1851, 2, 4.
Science quotes on:  |  Heat (90)

In this house, we OBEY the laws of thermodynamics!
Character from The Simpsons, U.S. animated television show
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It has been suggested that thermodynamic irreversibility is due to cosmological expansion.
'Thermodynamics, Cosmology, and the Physical Constants', in J. T. Fraser (ed.), The Study of Time III (1973), 117-8.
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It was not easy for a person brought up in the ways of classical thermodynamics to come around to the idea that gain of entropy eventually is nothing more nor less than loss of information.
Letter to Irving Langmuir, 5 Aug 1930. Quoted in Nathan Reingold, Science in America: A Documentary History 1900-1939 (1981), 400.
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Laws of Thermodynamics
1) You cannot win, you can only break even.
2) You can only break even at absolute zero.
3) You cannot reach absolute zero.
Folklore amongst physicists.
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Scientists have long been baffled by the existence of spontaneous order in the universe. The laws of thermodynamics seem to dictate the opposite, that nature should inexorably degenerate toward a state of greater disorder, greater entropy. Yet all around
John Mitchinson and John Lloyd, If Ignorance Is Bliss, Why Aren't There More Happy People?: Smart Quotes for Dumb Times (2009), 274.
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Suppose we take a quantity of heat and change it into work. In doing so, we haven’t destroyed the heat, we have only transferred it to another place or perhaps changed it into another energy form.
From 'In the Game of Energy and Thermodynamics You Can’t Even Break Even', Smithsonian (Aug 1970), 1, No. 5, 6.
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The fundamental laws of the universe which correspond to the two fundamental theorems of the mechanical theory of heat.
1. The energy of the universe is constant.
2. The entropy of the universe tends to a maximum.
The Mechanical Theory of Heat (1867), 365.
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The history of thermodynamics is a story of people and concepts. The cast of characters is large. At least ten scientists played major roles in creating thermodynamics, and their work spanned more than a century. The list of concepts, on the other hand, is surprisingly small; there are just three leading concepts in thermodynamics: energy, entropy, and absolute temperature.
In Great Physicists (2001), 93.
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The increase of disorder or entropy with time is one example of what is called an arrow of time something that gives a direction to time and distinguishes the past from the future. There are at least three different directions of time. First, there is the thermodynamic arrow of time—the direction of time in which disorder or entropy increases. Second, there is the psychological arrow of time. This is the direction in which we feel time passes—the direction of time in which we remember the past, but not the future. Third, there is the cosmological arrow of time. This is the direction of time in which the universe is expanding rather than contracting.
In 'The Direction of Time', New Scientist (9 Jul 1987), 46.
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The laws of thermodynamics, as empirically determined, express the approximate and probable behavior of systems of a great number of particles, or, more precisely, they express the laws of mechanics for such systems as they appear to beings who have not the fineness of perception to enable them to appreciate quantities of the order of magnitude of those which relate to single particles, and who cannot repeat their experiments often enough to obtain any but the most probable results.
Elementary Principles in Statististical Mechanics (1902), Preface, viii.
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The production of motion in the steam engine always occurs in circumstances which it is necessary to recognize, namely when the equilibrium of caloric is restored, or (to express this differently) when caloric passes from the body at one temperature to another body at a lower temperature.
'Réflexions sur la Puissance Motrice du Feu et sur les Machines Propres a Développer cette Puissance' (1824). Trans. Robert Fox, Reflexions on the Motive Power of Fire (1986), 64.
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Thermodynamics is a funny subject. The first time you go through it, you don’t understand it at all The second time you go through it, you think you understand it, except for one or two points. The third time you go through it, you know you don't understand it, but by that time you are so used to the subject, it doesn't bother you anymore.
Quoted, without citation, in Stanley W. Angrist and Loren G. Hepler, Order and Chaos: Laws of Energy and Entropy (1967), 215. The authors identify it as “perhaps apocryphal.” The quote is used as epigraph, dated as 1950 in Anton Z. Capri, Quips, Quotes, and Quanta: An Anecdotal History of Physics (2011), 50. The quote is introduced as “When asked why he did not write on that field he replied somewhat as follows,” by Keith J. Laidler in Physical Chemistry with Biological Applications (1978), 145.
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To my knowledge there are no written accounts of Fermi’s contributions to the [first atomic bomb] testing problems, nor would it be easy to reconstruct them in detail. This, however, was one of those occasions in which Fermi’s dominion over all physics, one of his most startling characteristics, came into its own. The problems involved in the Trinity test ranged from hydrodynamics to nuclear physics, from optics to thermodynamics, from geophysics to nuclear chemistry. Often they were closely interrelated, and to solve one’it was necessary to understand all the others. Even though the purpose was grim and terrifying, it was one of the greatest physics experiments of all time. Fermi completely immersed himself in the task. At the time of the test he was one of the very few persons (or perhaps the only one) who understood all the technical ramifications.
In Enrico Fermi: Physicist (1970), 145
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To pick a hole–say in the 2nd law of Ωcs, that if two things are in contact the hotter cannot take heat from the colder without external agency.
Now let A & B be two vessels divided by a diaphragm and let them contain elastic molecules in a state of agitation which strike each other and the sides. Let the number of particles be equal in A & B but let those in A have equal velocities, if oblique collisions occur between them their velocities will become unequal & I have shown that there will be velocities of all magnitudes in A and the same in B only the sum of the squares of the velocities is greater in A than in B.
When a molecule is reflected from the fixed diaphragm CD no work is lost or gained.
If the molecule instead of being reflected were allowed to go through a hole in CD no work would be lost or gained, only its energy would be transferred from the one vessel to the other.
Now conceive a finite being who knows the paths and velocities of all the molecules by simple inspection but who can do no work, except to open and close a hole in the diaphragm, by means of a slide without mass.
Let him first observe the molecules in A and when lie sees one coming the square of whose velocity is less than the mean sq. vel. of the molecules in B let him open a hole & let it go into B. Next let him watch for a molecule in B the square of whose velocity is greater than the mean sq. vel. in A and when it comes to the hole let him draw and slide & let it go into A, keeping the slide shut for all other molecules.
Then the number of molecules in A & B are the same as at first but the energy in A is increased and that in B diminished that is the hot system has got hotter and the cold colder & yet no work has been done, only the intelligence of a very observant and neat fingered being has been employed. Or in short if heat is the motion of finite portions of matter and if we can apply tools to such portions of matter so as to deal with them separately then we can take advantage of the different motion of different portions to restore a uniformly hot system to unequal temperatures or to motions of large masses. Only we can't, not being clever enough.
Letter to Peter Guthrie Tait (11 Dec 1867). In P. M. Harman (ed.), The Scientific Letters and Papers of James Clerk Maxwell (1995), Vol. 2, 331-2.
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War and the steam engine joined forces and forged what was to become one of the most delicate of concepts. Sadi Carnot … formed the opinion that one cause of France’s defeat had been her industrial inferiority. … Carnot saw steam power as a universal motor. … Carnot was a visionary and sharp analyst of what was needed to improve the steam engine. … Carnot’s work … laid the foundations of [thermodynamics].
In The Second Law (1984), 1-2.
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We define thermodynamics ... as the investigation of the dynamical and thermal properties of bodies, deduced entirely from the first and second law of thermodynamics, without speculation as to the molecular constitution.
The Scientific Papers of James Clerk Maxwell (2003), 664-665.
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With thermodynamics, one can calculate almost everything crudely; with kinetic theory, one can calculate fewer things, but more accurately; and with statistical mechanics, one can calculate almost nothing exactly.
Edward B. Stuart, Alan J. Brainard and Benjamin Gal-Or (eds.), A Critical Review of Thermodynamics (1970), 205.
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Carl Sagan Thumbnail In science it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion. (1987) -- Carl Sagan
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