Zeroth law Definition and 15 Threads

The zeroth law of thermodynamics states that if two thermodynamic systems are each in thermal equilibrium with a third system, then they are in thermal equilibrium with each other. Accordingly, thermal equilibrium between systems is a transitive relation.
Two systems are said to be in thermal equilibrium with respect to each other if they are linked by a wall permeable only to heat and they do not change over time. As a convenience of language, the same is also sometimes said of unlinked systems that would not change if they did have such a wall.
The physical meaning is expressed by Maxwell in the statement: "All heat is of the same kind". Another statement of the law is "All diathermal walls are equivalent".The law is important for the mathematical formulation of thermodynamics, which depends on the assertion that the relation of thermal equilibrium is an equivalence relation, The condition justifies the use of practical thermometers.

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  1. Z

    Chemistry How to understand the zeroth law through these specific equations?

    I've seen this math also in a lecture once. It seems very vague to me. Here is the relevant part of the book ##F_1## and ##F_2## are introduced as seen above. There is, as far as I can tell, no previous mention of them. Why does ##F_1(P_A,V_A,P_B,V_B)=0## signify thermal equilibrium...
  2. QuasarBoy543298

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  3. QuasarBoy543298

    The zeroth law of thermodynamics

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  4. A

    How can the simplification of equation I.4 using equation I.5 be justified?

    I was studying zeroth law from MIT Courseware (http://ocw.mit.edu/courses/physics/8-333-statistical-mechanics-i-statistical-mechanics-of-particles-fall-2013/lecture-notes/MIT8_333F13_Lec1.pdf). On page 2, it is mentioned that equation I.4 can be simplified using equation I.5 by cancelling the...
  5. J

    What is the Zeroth Law of Thermodynamics and why is it causing confusion?

    This is not a homework problem. I want to relay a statement made by my professor. From his online script: "0th law of thermodynamics: If two subsystems I,II are separately in thermal contact with a third system, III, then they are in thermal equilibrium with each other." He stated this in...
  6. Ravyan Asro

    Does temperature in special relativity depend on the frame of observation?

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  7. T

    Zeroth law of thermodynamics and empirical temperature

    In these lecture notes (http://ocw.mit.edu/courses/physics/8-333-statistical-mechanics-i-statistical-mechanics-of-particles-fall-2007/lecture-notes/lec1.pdf ), they get the equation: F_{AC} (A_1, A_2, \ldots; C_2, C_3, \ldots) = F_{BC} (B_1, B_2, \ldots; C_2, C_3, \ldots) Then they claim...
  8. B

    Zeroth law of thermodynamic and definition of temperature

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  9. L

    Question related to Zeroth law of thermodynamics

    I have given enough thought to this but couldn't get anywhere.I would be glad if you express your thoughts on this. Q:Zeroth law of thermodynamics is not valid for which one of the following, (a) 50 ml of water at 25°C is mixed with 150 ml of water at 25°C (b) 500 ml of milk at 15°C...
  10. R

    Is there an equation to prove the Zeroth law of thermodynamics?

    Is there a formula/equation that proves the Zeroth law, that can be confirmed by experiments? And another quick question. If I bunch together three temperatures (all water, of the same volume). Let's say 10 degrees Celsius, 5 degrees Celsius and 15 degrees Celsius. Is there an way of working...
  11. D

    Zeroth law of thermodynamics and thermometers

    the 0th law of thermodynamics states that if 2 systems A and C are in thermodynamic equilibrium with a 3rd system B, then A and C are in thermodynamic equilibrium. in other words, if A has the same temperature as B and B has the same temperature as C, then A has the same temperature as C...
  12. D

    Is Newtons law of cooling related to the zeroth law of thermodynamics?

    Being that both laws explain some kind of heat transfer I was wondering if they are in any way related.
  13. T

    Zeroth law of thermodynamics in terms of heat

    Is there any definition of the zeroth law of termodynamics using the heat concept? And does the zeroth law imply that the only way 2 systems can transfer energy is if they're not in thermal equilibrium? If 1 system is transferring energy to another one, that means they're not in thermal...
  14. L

    Feynman Lectures and the Zeroth Law of Thermodynamics

    In Volume 1 of the Feynman Lectures on Physics, Feynman derives the ideal gas law from Newton's laws of motion. But then on page 41-1, he puts a caveat to the derivation he has just completed: "We have perpetually been making a certain important assumption, which is that if a given system is in...
  15. B

    Zeroth Law of Thermodynamics

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