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.
Insert awesome title here
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.
Established Member
You have it right so far.Originally Posted by Glom
Established Member
<--Not sure if the last one is a joke or not.
<--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!
Moderator
don't forget pinball with Windows 2000 or XP
can anything with Microsoft Windows be 100% efficient
Order of Kilopi
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.
Established Member
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.
Established Member
On this board we obey the Laws of Thermodynamics!!!! :wink: :wink:
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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.
Order of Kilopi
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?)
Established Member
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.You have it right so far.
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.
Established Member
Dont forget law #7
All rules are inherently made by women and therefore are subject to change without notice or approval.
Administrator
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://www.physlink.com/Education/AskExperts/ae280.cfm
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.
Vulcan Administrator
There is NO law 6!
Everything I need to know I learned through Googling.
Order of Kilopi
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.
Established Member
We sure do... =D>
Established Member
Thanks for the reminder, Bruce.There is NO law 6!
Order of Kilopi
[-X When in doubt...see rule 7!Thanks for the reminder, Bruce.There is NO law 6!
Order of Kilopi
This is also known as Sturgeon's Law.sixth law: 90% of everything is crud.
Established Member
"...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?
Order of Kilopi
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?
Established Member
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.
Established Member
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.
Established Member
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..."
Administrator
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!""...and Lisa, we obey the Laws of thermodynamics IN THIS HOUSE" - Homer J. Simpson
Insert awesome title here
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.
Established Member
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.
Order of Kilopi
Ironically, entropy seems to working with your teachers mental process. To bad you are getting the "heat". :wink:
Honored Member
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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