# Thread: The Laws of Thermodynamics

1. ## The Laws of Thermodynamics

Just checking what's what.

Zeroth law.
Absolute zero cannot be experimentally reached.

First law.
Energy can neither be created nor destroyed.

Second law.
100% efficiency is not attainable.

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## Re: The Laws of Thermodynamics

Originally Posted by Glom
Just checking what's what.

Zeroth law.
Absolute zero cannot be experimentally reached.

First law.
Energy can neither be created nor destroyed.

Second law.
100% efficiency is not attainable.
You have it right so far.

3. &lt;--Not sure if the last one is a joke or not.
&lt;--Pretty sure it's not.

Why isn't Abolute Zero unattainable experimentally? Because you'd need a perfect vacuum and such?

Of course 100% efficiency isn't attainable! Not with things like Tetris, Solitare and the penguin and yeti game available to your employees!

4. don't forget pinball with Windows 2000 or XP

can anything with Microsoft Windows be 100% efficient

5. ## Re: The Laws of Thermodynamics

Originally Posted by Glom
Just checking what's what.
Second law.
100% efficiency is not attainable.
Of course, as a result, this means many things.

My favorite version is..."heat won't flow from a cooler to a hotter, you can try if you like, but you far better notter!" - my old thermo book - Simmang.

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Originally Posted by xbck1
Why isn't Abolute Zero unattainable experimentally? Because you'd need a perfect vacuum and such?
Well, you first need an environment that is not going to be influenced by the outside conditions.

Then you need to be able to achieve absolute zero conditions in that environment.

Now even if you could do the above, it would be next to impossible to confirm it since any instruments that would measure the conditions in there would cease to function when the temp reaches 0 K.

So while in theory you can achieve it, you will never be able to prove it.

7. On this board we obey the Laws of Thermodynamics!!!! :wink: :wink:

8. Classically, I believe the rule goes that in order to reach absolute zero, you'd need to have something below absolute zero to take the heat away, which is of course nonsensical.

Quantumly, absolute zero defies the Heisenberg Uncertainty Principle. In order that we not know exactly how fast a particle is moving, even at lowest energy states, it still has energy and hence motion, called zero point fluctuations. Also, even if you could get to absolute zero, you couldn't know it because you'd have to bombard the particle with energy to detect it and hence setting it in motion again.

9. As I vaguely recall, entropy is applied to get to extremely low temperatures. I want to say the mass is given magnetic alignment then, after cooling further, the magnet is removed creating disorder and ejecting heat. (Or am I even close?)

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## Re: The Laws of Thermodynamics

Originally Posted by Drakheim
Originally Posted by Glom
Just checking what's what.

Zeroth law.
Absolute zero cannot be experimentally reached.

First law.
Energy can neither be created nor destroyed.

Second law.
100% efficiency is not attainable.
You have it right so far.
No, the zeroth law is thermal equilibrium: if A and B are at the same temperature, and B and C are at the same temperature, then A and C are at the same temperature.

It's the third law that states that absolute zero cannot be reached by any finite process.

Then there's the fourth law: beer is good

fifth law: men turn into (derogatory anatomical epithet)s when driving sports cars

sixth law: 90% of everything is crud.

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Dont forget law #7

All rules are inherently made by women and therefore are subject to change without notice or approval.

12. I always liked this version of the three laws (not including the zeroth):
- you can't win
- you can't break-even
- you can't get out of the game.

http://en.wikipedia.org/wiki/Thermodynamics

Some alternative, serious definitions:

First Law: Energy Can Be neither Created nor Destroyed
Second Law: The Entropy of an Isolated System always Increases
Third Law: The Entropy of a Perfect Crystal at Absolute Zero is Zero

Zeroth law: Thermodynamic equilibrium. If A and B are in thermodynamic equilibrium, and B and C are in thermodynamic equilibrium, then A and C are also in thermodynamic equilibrium.
1st Law: Conservation of energy.
2nd Law: It is impossible to obtain a process such that the unique effect is the subtraction of a positive heat from a reservoir and the production of a positive work. Specifically, A system operating in contact with a thermal reservoir cannot produce positive work in its surroundings (Kelvin)
3rd Law: All processes cease as temperature approaches zero.

13. ## Re: The Laws of Thermodynamics

Originally Posted by swansont
sixth law: 90% of everything is crud.
There is NO law 6!

14. Originally Posted by Swift
I always liked this version of the three laws (not including the zeroth):
- you can't win
- you can't break-even
- you can't get out of the game.

http://en.wikipedia.org/wiki/Thermodynamics

Some alternative, serious definitions:

First Law: Energy Can Be neither Created nor Destroyed
Second Law: The Entropy of an Isolated System always Increases
Third Law: The Entropy of a Perfect Crystal at Absolute Zero is Zero

Zeroth law: Thermodynamic equilibrium. If A and B are in thermodynamic equilibrium, and B and C are in thermodynamic equilibrium, then A and C are also in thermodynamic equilibrium.
1st Law: Conservation of energy.
2nd Law: It is impossible to obtain a process such that the unique effect is the subtraction of a positive heat from a reservoir and the production of a positive work. Specifically, A system operating in contact with a thermal reservoir cannot produce positive work in its surroundings (Kelvin)
3rd Law: All processes cease as temperature approaches zero.
Kelvin's 2nd law is odd to me. By "reservoir" does he mean "sump" (waste heat)? Many process utilize a thermal source for producing work. Oh wait, I see, he means 100% conversion from heat to work can not be accomplished. Key word here is "unique". 8)

I really like "can't get out of the game". More gripping than usual.

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Originally Posted by cyswxman
On this board we obey the Laws of Thermodynamics!!!! :wink: :wink:
We sure do... =D>

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## Re: The Laws of Thermodynamics

Originally Posted by ToSeek
Originally Posted by swansont
sixth law: 90% of everything is crud.
There is NO law 6!
Thanks for the reminder, Bruce.

17. ## Re: The Laws of Thermodynamics

Originally Posted by Wiley
Originally Posted by ToSeek
Originally Posted by swansont
sixth law: 90% of everything is crud.
There is NO law 6!
Thanks for the reminder, Bruce.
[-X When in doubt...see rule 7!

18. sixth law: 90% of everything is crud.
This is also known as Sturgeon's Law.

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Originally Posted by cyswxman
On this board we obey the Laws of Thermodynamics!!!! :wink: :wink:
"...and Lisa, we obey the Laws of thermodynamics IN THIS HOUSE" - Homer J. Simpson

Edit: Incidentally, this is one of the reasons why I doubt the reports of an accelerating force in the Universe (or the so-called Cosmological Constant). If it were so, where would the energy come from? Would not the effect of this energy be to reduce the entropy of the Universe?

20. I agree with you there, Diamond;

The laws of thermodynamics are descriptive, not prescriptive; they are indispensible to physics and engineering, yet the universe as a whole does not seem to follow them.

Consider this;
the cosmological constant implies a force existing in empty space exerting a pressure on the universe itself which causes it to expand; in one model I have encountered, the force remains the same per unit volume -but the number of unit volumes is increasing -!

So the universe becomes an enormous free lunch, which gets bigger while you are eating it.

Where are your laws of thermodynamics now, Lord Kelvin?

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Originally Posted by Kaptain K
sixth law: 90% of everything is crud.
This is also known as Sturgeon's Law.
Thanks - I did not know that!

I also like Hofstadter's law: It alsways take longer than you think, even when you take into account Hofstadter's law.

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Then there's Godwin's Law, as demonstrated on 'certain' fora on a regular basis:

"As an internet discussion grows longer, the probability of a comparison involving Nazis or Hitler approaches one." Its then standard procedure that the side making said comparison is considered to have lost.

23. Oooo, physics moment!
Today in economics we were discussing renewable energy sources. Class was going along fine and dandy until I pointed out that, according to the second law of thermodynamics, no energy source is truly reusable and everything we do still contributes to the heat death of the universe (yay for entropy!).
My teacher's response, "you know, up until now I was going to congratulate you at the end of the period for being unusually focused today..."

24. Originally Posted by Diamond
Originally Posted by cyswxman
On this board we obey the Laws of Thermodynamics!!!! :wink: :wink:
"...and Lisa, we obey the Laws of thermodynamics IN THIS HOUSE" - Homer J. Simpson
I always wanted to get t-shirts made up, one with Newton, one with Einstein, in the Uncle Sam pose, with the quote "Gravity, it's not a good idea, it's the LAW!"

25. Originally Posted by Andromeda321
Oooo, physics moment!
Today in economics we were discussing renewable energy sources. Class was going along fine and dandy until I pointed out that, according to the second law of thermodynamics, no energy source is truly reusable and everything we do still contributes to the heat death of the universe (yay for entropy!).
My teacher's response, "you know, up until now I was going to congratulate you at the end of the period for being unusually focused today..."
Say what? Your teacher didn't congratulate you because you forced a realisation that ultimately everything is subject to the laws of physics?

I hate people who think their political motives are so high and mighty they can disregard science.

26. What she didn't mention was that after she made mention of physics, she threw an apple at the teacher to prove that Newton was right.

27. Originally Posted by Andromeda321
Oooo, physics moment!
Today in economics we were discussing renewable energy sources. Class was going along fine and dandy until I pointed out that, according to the second law of thermodynamics, no energy source is truly reusable and everything we do still contributes to the heat death of the universe (yay for entropy!).
My teacher's response, "you know, up until now I was going to congratulate you at the end of the period for being unusually focused today..."
Ironically, entropy seems to working with your teachers mental process. To bad you are getting the "heat". :wink:

28. Originally Posted by Andromeda321
Oooo, physics moment!
Today in economics we were discussing renewable energy sources. Class was going along fine and dandy until I pointed out that, according to the second law of thermodynamics, no energy source is truly reusable and everything we do still contributes to the heat death of the universe (yay for entropy!).
My teacher's response, "you know, up until now I was going to congratulate you at the end of the period for being unusually focused today..."
So your economics teacher needed all those words, which included an ad hominem, to say, "I don't understand what you said."?

I bet balancing a checkbook is more than that teacher can handle! :roll:

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