An Open and Closed Case

[Progenitor A]

There has been great confusion and contradiction about entropy

Not thermodynamic entropy - I think that everyone is agreed that when work is done, some energy is always 'wasted' and much of that wasted energy is converted into unusable forms

This law is normally couched in terms of 'closed' thermodynamic systems - that is systems in which the total energy remains constant, no 'new' energy is introduced and no energy is lost; some of the energy within that closed system is usable, some is not.

The reason for introducing the concept of a 'closed' system is quite straightforward, it simplifies the concept of thermodynamic entropy and does not allow distraction from the central concept of thermodynamic entropy that is hence starkly defined

Exactly the same thermodynamic entropy the 'wastage' of energy occurs in 'open' systems too, but the 'usable' energy may increase because new energy may be introduced. (Of course energy may also be lost from an 'open' system, increasing the entropy rate!)


All this accords with our experience, our intuition and our common sense

Unfortunately all these reliable indicators of soundness-of-mind and reliability of idea simply evaporate when we move away from thermodynamic entropy and consider entropy in terms of order-to-disorder.

Why is this?

Why is order-to disorder entropy apparently so much more difficult to understand than thermodynamic entropy?
Why is order-disorder entropy apparently riddled with contradictions whereas thermodynamic entropy is not?

Some quite intelligent people absorb these contradictions and yet claim to 'understand' order-to-disorder entropy. If any other physical theory contradicted itself these same people would laugh it out of court.
The real apparent contradiction of order-to disorder entropy is that we see all around us contradictory evidence
We see everywhere the opposite, disorder-to-order.

The normal response to this contradictory evidence of disorder-to-order is that it 'only occurs in 'open' systems'

But a small pause to consider this riposte shows that it is nonsensical. Disorder-to-order occurs in both 'open' and 'closed' systems.

Perhaps the problem is that no-one has payed particular attention to the definition of 'order'. Cox did attempt to on his recent TV programme, and that has been forwarded on these boards - that is that order is defined as the improbability of a structure.
That seems good enough to me in fact

So some apparent contradictions about order-to disorder entropy must be accepted and challenged and some misleading shibboleths abandoned

The biggest barrier that I see to gaining a coherent understanding of order-to-disorder entropy, the shibboleth that should be abandoned as a mantra of obfuscation is the use of 'open' and 'closed' thermodynamic systems when discussing order-to-disorder entropy

Of course order-to -disorder entropy is related to, is a function of, thermodynamic entropy, but neither have anything to do with open or closed thermodynamic systems

So, let's close the book on 'open' and 'closed' systems.

They were introduced to simplify the concept of thermodynamic entropy, and can be dispensed with once we understand thermodynamic entropy

There is an explanation of order-to-disorder entropy as a function of thermodynamic entropy that does not depend upon mantras that lead to contradiction

[speakertoanimals]

All this accords with our experience, our intuition and our common sense

Ah, that's where you've gone wrong then, since the main point about understanding entropy is that it isn't intuitive!

Why is order-disorder entropy apparently riddled with contradictions whereas thermodynamic entropy is not?

Except you haven't shown there are any contradictions, just that you don't understand statistical entropy.

What is paramount is statisticalentropy, the thermodynamic entropy can then be derived from the statistical one. The clus is in the fact that temperature itself is a purely statistical concept, you can define it for macroscopic systems, but not for a single particle. Hence since temperature is purely statistical, so is thermodynamic entropy, in effect, since it involves energy (which can be defined for any system), and temperature which can only be defined for systems composed of many particles.

They were introduced to simplify the concept of thermodynamic entropy, and can be dispensed with once we understand thermodynamic entropy

This is wrong. Open and closed systems are fundamental to any discussion of this topic, statistical or thermodynamic. And indeed, we don't get the second law at all unless we draw a distinction between systems which are open and systems which are closed, that is kind of the whole point about the second law!

To understand thermodyanamic entropy, you need to understand it as derived from statistical entropy, hence you need to start by understanding that. You can't start from the other end.

[Progenitor A]

You would be well advised to stop blathering and try thinking

You have demonstrated elsewhere that disorder-to-order 'entropy' occurs not only in 'open' but also in 'closed' thermodynamic systems (albeit in an abortive attempt to show that disorder-to-order entropy cannot occur in a closed system; the fact that you contradict yourself does not appear to occur to you, or if it does occur, does not appear to bother you in the slightest!)

[speakertoanimals]

You have demonstrated elsewhere that disorder-to-order 'entropy' occurs in ot only in 'open' but also in 'closed' thermodynamic systems ...........

O stop repeating the SAME nonsense! Entropy is an extensive quantity, hence the total entropy of a system is the sum of the entropies of any sub-systems, Hence you can have LOCAL regions of increasing order WITHIN a closed system, but only because you are considering the entropy of a sub-system of that entire closed system. When you consider the entire closed system, the total entropy can only ever increase or stay constant, even though the entropy of a sub-system may decrease, as long as that sub-system is open....................

You would be well advised to stop blathering and try thinking

Well, this has just degenerated into your usual repeat/repeat/repeat the same nonsense.

You're either really as ignorant of thermodyanmics as you pretend to be, or just on yet another wind-up, both of which are SAD statements about you, whichever is the truth. Hence, yet again, end to discussion (not that it ever got going, frankly!).

Now lets wait for your usual attenmpts to lure me back onto this thread, before you go and start yet another thread on a similar topic, whilst CLAIMING that you have clearly shown I'ma total idiot. Boring and repetitive, that's the best you can mange. Why you would bother is still beyond me................You must have a very sad life if this looks like FUN..................

[Progenitor A]

And now, my lovely and devoted admirers, I will take one closed thermodynamic system, unt voila, I will create order out of disorder and show that the the thermodynamic entropy, although increased, is INDEED far less than the order I will impose!

IM-POSSIBLE I hear my sceptical but loving audience say!

I know, I know, my small peaches, but I will DEMONSTRATE the IM-POSSIBLE; just for YOU the maestro will make the IM-POSSIBLE POSSIBLE!!

In my closed thermodynamic system I have a machine driven by petrol that can do WORK

There is a shelf and below a vandalised pile of books, to which I will restore ORDER by picking them UP with my machine and placing them on the SHELF!

Uno momento!
My machne has started. I am now picking up the BOOKS and placing them on the SHELF!

There are a lot of books, so my spendidly lovely audience can take a beverage break whilst I continue!......

Voila!
Finito!

The work is finito!

My trusty helper , handy with the electronic calculator tells me that the books weighed 9kg and the shelf is 1 metre high, so my machine has expended 9 Joules of Energy!

But, my backroom boffin informs me, my machine is only 90% efficient!
All that clanging, all that heat, he tells me, consumed another 1 Joules of energy!
He also tells me, my dears that that energy is wasted!

So although I have made order out of disorder, I have expended 10 Joules of energy in doing so!

But 9 Joules of that is recoverable energy isn't it my dears!

So I have created ORDER out of DISORDER and wasted just 1 Joule of energy.

If only my machine was 99% efficient i could have created ORDER out of DISORDER and only wasted 0.09 Joules!

I asked my resident boffin if I could have a 100% efficient engine but he tells me NON - that would infringe , he tells me the 2nd Law of Thermodynamics which apparently has it that whenever work is done, energy is 'wasted', and that cannot be avoided!

But nevertheless my dears, it is, DEMONSTRATED as PROMISED that your beloved Maestro has, within a CLOSED system created ORDER from DISORDER at the cost of only 1 JOULE, because the 9 Joules put into my ORDERED SYSTEM is recoverable!

Thank you!
THANK YOU!!

(Blows kisses and exuants right)

[speakertoanimals]

Except noone ever said that you couldn't create some order in a closed system, as long as you createdmore disorder elsewhere.

Not a great example though, since the energy input to the books mostly served to just raise them to the shelf, and would have expended the same amount if you'd raised the disordered pile of books to the same height!

The only order was putting them in order,and what matters there is the instructions you gave to your robot,and did that come from outside. And o dear, we are back to information theory.....................

Must try harder! Height is not order!

[Progenitor A]

Well, well, look at what our resident physicist has just said!!

Mar 26, 2011 19:40:30 GMT 1 speakertoanimals said:

Except noone ever said that you couldn't create some order in a closed system, .......

;D ;D ;D

Anyone spot the self-contradictions below?
No prizes offered!
;D ;D

Mar 24, 2011 13:57:31 GMT 1 speakertoanimals said:

(Naymissus)....that disorder-to order does occur in closed and open systems

NOT closed systems, else you are saying the second law is wrong!

Mar 10, 2011 13:55:44 GMT 1 speakertoanimals said:

(Naymissus)....However this trend toward increasing entropy is not absolute and we can also have order arising out of disorder as time progresses - e.g. London.
Unfortunately Professor Cox's definition of order arising from disorder defining the direction of time means we have time reversal locally (although the general trend toward disorder continues.)
....

This is NONSENSE. The point about the second law and the thermodynamuic arrow of time is that ity talks about the entropy OF A CLOSED SYSTEM. London isn't.

Mar 10, 2011 21:32:58 GMT 1 speakertoanimals said:

Because the second law ONLY applies to a closed system,

Mar 15, 2011 22:33:56 GMT 1 speakertoanimals said:

....we only see order increasing in non-closed systems, ...

Mar 21, 2011 13:09:55 GMT 1 speakertoanimals said:

Except that is precisely what the second law of thermodynamics does say. That creating order (decreasing entropy) cannot happen in a closed system.

Mar 21, 2011 17:58:06 GMT 1 speakertoanimals said:

(Naymissus)They evidently are not. In a closed system we always have thermodynamic disorder increasing, but we can have structures of increasing complexity and organisation.

Only if you are willing to throw the second law of thermodynamics out the window!

Mar 21, 2011 13:09:55 GMT 1 speakertoanimals said:

(Naymissus)....It is nonsense to say that it applies to only closed thermodynamic systems.

Whcih seems to be saying that it is self-evident that the second law of thermodyanmics is NOT true.

Or simpler explanation, NM hasn't a clue when it comes to entropy....

Mar 18, 2011 15:35:08 GMT 1 speakertoanimals said:

(Naymissus)....I simply assumed a closed system, as Cox assumed (without any justification) that the universe is a closed system

.... the universe as the whole shebang, then that is by definition closed..

[speakertoanimals]

Just insert TOTAL entropy where appropriate...............

I obviously made the error of assuming that readers understood the basic terminology, knew that entropy was extensive, and so understood what was meant by the entropy of a closed system, or the entropy of a sub-system...........................

Plus thanks for the books example, just showed that you don't know what entropy is anyway, so what is the point.............

(None, and there never was, just another daft wind-up from someone who doesn't CARE if they cause confusion in their quest for some sort of sad entertainment..................)

[Progenitor A]

Mar 28, 2011 13:04:53 GMT 1 speakertoanimals said:

Just insert TOTAL entropy where appropriate...............

I obviously made the error of assuming that readers understood the basic terminology, knew that entropy was extensive, and so understood what was meant by the entropy of a closed system, or the entropy of a sub-system...........................

Plus thanks for the books example, just showed that you don't know what entropy is anyway, so what is the point.............

(None, and there never was, just another daft wind-up from someone who doesn't CARE if they cause confusion in their quest for some sort of sad entertainment..................)

;D ;D ;D ;D ;D ;D