Is the law of Entropy wrong?

[MirceaKitsune]

There's no scientific law or term that I can possibly contradict. Although there is a small exception to this rule, which I've pondered for a bit now. That's the law of Entropy... with the statement that "everything tends from order to disorder". The reason why I find this statement incorrect might be obvious; I don't believe that things constantly tend from one to the other, but back and forth between the two.

 

Of course, it depends on how someone sees these words. Myself, I understand order as everything being sorted in a neat pattern, or arranged based on a set of logics. Whereas disorder is something being moved around chaotically, or simply broken and splattered all over. Hopefully I'm not wrong about something so obvious, as change alone might be interpreted as disorder too.

 

So why do I question that this statement might be wrong? Well, there's certainly more things likely to cause disorder over order. To use the simplest example, taking a basket full of apples and spilling it all over the garden is easier and requires less energy than doing the opposite, which is talking an empty basket and placing every apple in the garden inside. But both exist and manifest throughout the universe.

 

When it comes to disorder, it's easy to find examples; Meteors flying all over the place and smashing into each other, suns exploding and throwing their energy and gases into space, planetary storms causing materials of all sorts to mix together, and more... while virtually anything becoming unstable can be a trigger for disorder. But what about order? In my view, there are at least two primary forces in the universe which bring things from disorder to order; Gravity and intelligence.

 

Intelligent life is obvious; People who combine dirt and powder to obtain cement with which they make buildings with perfectly aligned walls, or simply someone sorting through their tool box to put every screw of a certain size in the right compartment. We could also say that biology itself tends toward order... as various materials are shaped based on strict patterns (bones, internal organs, etc). Gravity is also a mechanism who's purpose can actually be seen as bringing order, because it pulls things together and lets them sort themselves out. When tons of dust float around space, they gather to form a sphere (planet) which theoretically tends toward a perfectly round shape. Another example of how gravity brings order is that in some cases, it separates mixed materials. Put oil in water... at first the two will be all over one another, but eventually one floats to the top while the other remains at the bottom. Or try throwing a hand of dirt into a lake... the dirt will float through the water for a bit but soon settle at the bottom.

 

So why is the statement that "everything tends from order to disorder" still used, and not changed into "everything tends between order and disorder"? Isn't that more correct, or am I missing something?

Edited June 6, 2014 by MirceaKitsune

[Mordred]

your not wrong, entropy can go from disorder to order, however you need to be careful the second law states

 

The second law of thermodynamics states that the entropy of an isolated system never decreases, because isolated systems always evolve toward thermodynamic equilibrium, a state with maximum entropy.

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

 

the other key factor is entropy is a state function

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

 

the second law generally holds try for irreversible processes, not for reversible processes.

 

http://www.physics.ohio-state.edu/p670/textbook/Chap_6.pdf

 

as far as entropy being used in terms of general disorder vs order, I've always found this usage outside of thermodynamics to be misleading and a poor use of entropy

[studiot]

 

as far as entropy being used in terms of general disorder vs order, I've always found this usage outside of thermodynamics to be misleading and a poor use of entropy

 

 

Yes the words order and disorder, in the context of the second law, have particular meanings that are not associated with a housewife's apple pie order or the OP example of perfectly round shapes.

 

 

the second law generally holds try for irreversible processes, not for reversible processes.

 

The second law holds for both reversible and irreversible cyclic processes. It's use on noncyclic processes can lead to error.

 

 

The second law of thermodynamics states that the entropy of an isolated system never decreases, because isolated systems always evolve toward thermodynamic equilibrium, a state with maximum entropy.

 

Yes it never decreases, but that is not the same as saying evolve towards some maximum entropy. It is possible to construct examples that do not do this.

[Mordred]

the last quote was from wiki, I should have looked at it closer lol,

 

doesn't a reversible process involve no change in entropy by definition?

 

"In thermodynamics, a reversible process -- or reversible cycle if the process is cyclic -- is a process that can be "reversed" by means of infinitesimal changes in some property of the system without entropy production (i.e. dissipation of energy)"

 

if this definition is correct, how would the second law apply to it?

 

or

The process in which the system and surroundings can be restored to the initial state from the final state without producing any changes in the thermodynamics properties of the universe is called a reversible process. In the figure below, let us suppose that the system has undergone a change from state A to state B. If the system can be restored from state B to state A, and there is no change in the universe, then the process is said to be a reversible process. The reversible process can be reversed completely and there is no trace left to show that the system had undergone thermodynamic change.

For the system to undergo reversible change, it should occur infinitely slowly due to infinitesimal gradient. During reversible process all the changes in state that occur in the system are in thermodynamic equilibrium with each other.

 

http://www.brighthubengineering.com/thermodynamics/4616-what-are-reversible-and-irreversible-processes/

Edited June 7, 2014 by Mordred

[studiot]

The Clausius statement of the second law is:-

 

[math]\oint {\frac{{dQ}}{T}} [/math][math] \le 0[/math]
The strict equality holds for reversible systems, the inequality for irreversible systems.

Edited June 7, 2014 by studiot

[Roamer]

Doesn't order realy mean it is easy for us to make a model of it ?

(whether this model is a scientific model or just a simple image in our head regarding something about everyday-life)

[MirceaKitsune]

Thank you, this clarifies a lot. Yeah, the statement that order goes toward disorder only might apply to a few restriced cases. But throughout the universe, it's back and forth between the two.

[studiot]

 

Thank you, this clarifies a lot. Yeah, the statement that order goes toward disorder only might apply to a few restriced cases. But throughout the universe, it's back and forth between the two.

 

 

You need to understand that the terms order and disorder are statistical statements that refer to probabilities.

 

Try this experiment:

 

Take two dice and roll them.

 

How many ways can their sum equal 2? : This is the lowest sum you can obtain.

How many ways can their sum equal 6?

 

In fact form a table from 2 to 12.

 

There is only one configuration that can yield a sum of 2, but there are many that can yield a sum of 6

 

so 6 is more probable than 2.

 

Now go a step further.

 

How many ways can the two numbers thrown be the same and how many ways can they be different?

 

Call the ways that they can be thrown the same 'order' and the ways they can be different, 'disorder'.

 

Which is more probable?

 

That is all that is meant by the statement disorder is more prebable than order or order tends to disorder.

 

Rewriting it says

 

When (in real life) there are a very large (perhaps infinite) number of states if we take any one state and call it order, then disorder is much more likely.

[MirceaKitsune]

Yes, disorder is certainly more likely and abundent, as I believe I stated as well. Order means a pattern, whereas disorder means random... and randomness is far more likely. Just saying that both happen in the universe, and I believe all / most particles go more or less between the two throughout their existence.

[Mordred]

tried to delete my last post was in error

Edited June 7, 2014 by Mordred

[studiot]

But the application of both the first and second laws to an isolated system is trivial since they involve non system quantities (those crossing the system boundary).

 

Both w and q are necessarily zero for an isolated system therefore dU is also zero.

[Mordred]

yeah I came to that conclusion but you replied when I tried deleting my previous post

 

this article cleared it up.

 

http://www.saylor.org/site/wp-content/uploads/2013/08/BolesLectureNotesThermodynamicsChapter6.pdf

Edited June 7, 2014 by Mordred

[studiot]

Thermodynamics is a very closely defined subject.

Unfortunately there is much 'loose talk' about it that leads people into erroneous conclusions.

 

Perhaps the worst for casual aquaintances with thermodynamics is the populist press propagated confusion over order and disorder.

 

For those who study deeper the commonest errors stem from failure to properly specify the full thermodynamic situation (System, boundary and process).

 

I note your original linked article is guilty of this for instance.

Edited June 7, 2014 by studiot

[Mordred]

yeah I found a few errors in it myself lol, however it was enough to conclude my previous understanding was in error or at least lacking in some aspects

atm I'm looking over this article, haven't drawn any conclusions as of yet

"THE PHYSICS AND MATHEMATICS OF THE SECOND LAW OF THERMODYNAMICS"

http://arxiv.org/pdf/cond-mat/9708200.pdf

Edited June 7, 2014 by Mordred

[studiot]

For those interested in theoretical thermodynamics (non engineering) I recommend.

 

Elements of Classical Thermodynamics for Students of Advanced Physics : Pippard : Cambridge

 

Thermodynamics and Statistical Mechanics : Wilson : Cambridge

 

Basic Thermodynamics : Carrington :: Oxford

 

Chemical Equilibrium : Denbeigh : Cambridge

 

I do not advise

 

Thermodynamics and and Introduction to Thermostatistics : Callen : Wiley.