How Many Laws of Thermodynamics Are There?

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Discussion Overview

The discussion centers around the number of laws of thermodynamics, with participants expressing differing views on whether there are four laws or only two. The conversation includes definitions and interpretations of the laws, as well as questions about the implications of absolute zero.

Discussion Character

  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants assert that there are four laws of thermodynamics, while others suggest there are only two, leading to confusion about the correct number.
  • One participant outlines the four laws: the 0th law regarding thermal equilibrium, the 1st law related to conservation of energy, the 2nd law stating that entropy increases over time, and the 3rd law stating that absolute zero cannot be reached.
  • Another participant humorously summarizes the laws in a non-technical manner, emphasizing the impossibility of reaching absolute zero.
  • A participant questions the reasoning behind the impossibility of reaching absolute zero, seeking further explanation.
  • One response suggests that reaching absolute zero would violate the Heisenberg Uncertainty Principle (HUP), indicating a connection between quantum mechanics and thermodynamics.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the number of laws of thermodynamics, with multiple competing views presented throughout the discussion.

Contextual Notes

Participants reference different interpretations and definitions of the laws, indicating potential limitations in understanding and agreement on the topic.

LENIN
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How many laws of thermodinamics are there?

This topic came up during one of our last hours of higschool physics. Some of us sead that there are 4 and some sead that there are only 2. In different books we also found different answeres. So now I really don't know which statement is corect. Any ideas?
 
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0th law - If a system, C is in thermal equilibrium with two other systems, A and B, then A and B must also be in thermal equilibrium.

1st law - Heat = Change in Internal Energy + Work done on the system. (Conservation of energy effectively).

2nd law - Entropy always increases with time.

3rd law - No object can ever reach a temperature of absolute zero.

A nice discussion of laws 1-3 can be found here.
http://www.physlink.com/Education/AskExperts/ae280.cfm

Claude.
 
1st Law: You can't win; you can only break even

2nd Law: You can only break even if you get to absolute zero.

3rd Law: You can't get to absolute zero.
 
rdt2 said:
1st Law: You can't win; you can only break even

2nd Law: You can only break even if you get to absolute zero.

3rd Law: You can't get to absolute zero.

you are forgetting a law here, see the above post

marlon
 
But i don't know why we can not reach the zero absolute temperature. Who can explain?
 
Essentially, because a particle at 0K violates the HUP. Google the 3rd law of thermodynamics and you should find some satisfying explanations.

Claude.
 

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