# thermodynamics

[ thur-moh-dahy-nam-iks ]

## noun

, (used with a singular verb)
1. the science concerned with the relations between heat and mechanical energy or work, and the conversion of one into the other: modern thermodynamics deals with the properties of systems for the description of which temperature is a necessary coordinate.

thermodynamics

/ ˌθɜːməʊdaɪˈnæmɪks /

## noun

1. functioning as singular the branch of physical science concerned with the interrelationship and interconversion of different forms of energy and the behaviour of macroscopic systems in terms of certain basic quantities, such as pressure, temperature, etc See also law of thermodynamics
“Collins English Dictionary — Complete & Unabridged” 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

thermodynamics

/ thûr′mō-dī-nămĭks /

1. The branch of physics that deals with the relationships between heat and other forms of energy. Four basic laws have been established.
2. ◆ The first law states that the amount of energy added to a system is equal to the sum of its increase in heat energy and the work done on the system. The first law is an example of the principle of conservation of energy.
3. ◆ The second law states that heat energy cannot be transferred from a body at a lower temperature to a body with a higher one without the addition of energy. Thus, warm air outside can transfer its energy to a cold room, but transferring energy out of a cold room to the air outside requires extra energy (as with an air conditioner).
4. ◆ The third law states that the entropy of a pure crystal at absolute zero is zero. Since there can be no physical system with lower entropy, all entropy is thus defined to have a positive value.
5. ◆ The zeroth law states that if two bodies are in thermal equilibrium with some third body, then they are also in equilibrium with each other. This law has its name because it was implicitly assumed in the development of the other laws, and is in fact more fundamental than the others, but was only later established as a law itself.

thermodynamics

1. The branch of physics devoted to the study of heat and related phenomena. The behavior of heat is governed by the three laws of thermodynamics: (1) The total energy of an isolated system cannot change; this is the law of conservation of energy . (2) Heat will not flow from a cold to a hot object spontaneously ( see entropy ). (3) It is impossible, in a finite number of operations, to produce a temperature of absolute zero .

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## Notes

All thermodynamic properties of matter can be understood in terms of the motion of atoms and molecules .
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## Other Words From

• thermo·dy·nami·cist noun
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## Word History and Origins

Origin of thermodynamics1

First recorded in 1850–55; thermo- + dynamics
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## Example Sentences

The mechanism is reversed entropy, which carries real meaning because entropy says something about the flow of time through the Second Law of Thermodynamics.

Ross has ingeniously located much of modern physics in the Bible, including the laws of thermodynamics and the Big Bang.

The result was the second fundamental law of thermodynamics.

Long did thermodynamics confine itself to the study of the dilatation of bodies and their changes of state.

It is obvious in mechanics and thermodynamics, and the theory of matter is another very good instance.

So that the terms introduced by Carnot in the second law of thermodynamics, viz.

If a should be a function of the temperature, it follows from thermodynamics that it would be equal to (a - Tda/dT) (1/vl - 1/vv).