ID Creationism and the Second Law

Great takedown. Thanks to RIchard for the link, Jason for the article and Mike Elzina for patiently trying to explain all of this over and over again.

… if all we see entering is radiation and meteorite fragments, it seems clear that what is entering through the boundary cannot explain the increase in order observed here.

Joe, the easiest way is to register for a local Movable Type account and log in with that. I don't think our Gmail support allows you to change your "handle".

Thanks Reed, and in case anyone wants to quibble, yes I am aware that some energy for life comes from chemoautotrophy. But most of it is from the sun.

Gee, another reason for me to be ashamed of my home state of Texas!

Why is it always the second law? Why not the first or third? (Or fourth if there's that many.)

Henry J said: Why is it always the second law? Why not the first or third? (Or fourth if there's that many.)

Ok, sorry to draw this way OT, but 4th LoT? Was this facetious? Or did the number change since intro stat mech?

dphorning said: Ok, sorry to draw this way OT, but 4th LoT? Was this facetious? Or did the number change since intro stat mech?

felsenst said: Jason Rosenhouse's flattening of Sewell is wonderful. Both he and Mark Perakh have previously flattened Sewell's earlier arguments (here and here), though Sewell seems to have learned nothing.

Joe Felsenstein said:

dphorning said: Ok, sorry to draw this way OT, but 4th LoT? Was this facetious? Or did the number change since intro stat mech?

The Fourth Law of Thermodynamics is that a commenter on a blog, when encountering a list like this of the "four laws of thermodynamics" (numbered 0, 1, 2, 3) will lose count when he posts about it. Us commenters have very limited conceptual abilities.

If they use zeroth law instead of 2nd they would hardly succeed. Because zeroth law makes evolution possible.

https://me.yahoo.com/a/x68O1lsNl5F6vhoVwwk5qw1CYaqjc3BB#ca44a said: If they use zeroth law instead of 2nd they would hardly succeed. Because zeroth law makes evolution possible.

Henry J said: Why is it always the second law? Why not the first or third? (Or fourth if there's that many.)

felsenst said: Jason Rosenhouse's flattening of Sewell is wonderful. Both he and Mark Perakh have previously flattened Sewell's earlier arguments (here and here), though Sewell seems to have learned nothing. I have also posted twice at PT making fun of Sewell's argument (here and here).

It has been quite painful watching the mangling of the second law by not just the ID/creationists, but also by well-intentioned people trying to make the essence of the second law accessible to the general public.

And I have been watching this since about the mid 1970s when I was first becoming aware that misconceptions about the second law were being promulgated.

None of the excellent textbooks I have known and used over the years make any reference to order/disorder when discussing entropy. The concept of the integral of dQ/dT was already becoming a useful pattern for making efficient calculations before Clausius named it in 1865; and certainly before statistical mechanics clarified just what temperature, internal energy, and accessible microstates are.

It is an equivalent way of stating that energy flows spontaneously from high temperature to low temperature. Dividing a quantity of heat, Q by a small T gives a larger number than dividing that same Q by a large T. Entropy spontaneously increases; DUH!

As I have tried to make clear (despite the attempted distractions by certain trolls), entropy comes down simply to the enumeration of energy microstates. How those microstates are connected with the microscopic constituents of the system and the degrees of freedom over which the energy is spread, how the number of microstates changes with the total energy of the system, these are what are important.

There is, in general, no consistent relationship between how energy is spread among microstates and the spatial ordering of atoms and molecules that provide those microstates. The use of order/disorder, if it is used at all (and it should NOT be used in this context), is only a metaphor drawn from visualizations of spatial arrangements of things typically used to teach the concepts of enumeration.

The second law basically comes down to the fact that energy spreads around. More fundamentally, however, energy spreads around because matter interacts with matter. This is a simple, observational fact. If that were not the case, there would be no universe as we know it. Energy must be released and spread around in order for matter to condense.

If a thermodynamic system is completely isolated from its surroundings, energy spreads among all available microstates until the maximum number of microstates is on the average occupied. Thus, Boltzmann’s constant times the logarithm of the number of microstates - i.e., entropy - increases to a maximum; DUH!

If the microscopic constituents of the thermodynamic system also did NOT interact with each other, then the system would remain in whatever particular microstate it is in. It would have zero entropy (logarithm of 1 is zero); but because it is also completely isolated from its surroundings, we wouldn’t know what state it was in.

And this fact should also reveal the ID/creationist lie that large entropy signifies “lack of information,” whatever the hell that means.

But the notions of entropy and microstates make it possible to relate the macroscopic states of a thermodynamic system to its underlying constituents. That is the true power of the concept of entropy. Entropy is just a name given to a mathematical calculation that makes such connections possible.

It has nothing to do with the universe coming all apart, with order/disorder, or with making evolution impossible. Evolution happens because matter condenses. And matter condensing requires the spreading around of energy.

Entropy is not about now advanced some organism is on some evolutionary scale. Over time, as matter condenses, more and more complex things emerge. Young organisms have less entropy (number of energy microstates consistent with its macroscopic state) that do larger adults. That doesn’t make the young “more advanced.”

Entropy is about counting the number of energy microstates consistent with the macroscopic state of any thermodynamic system. It does not have to be any more complicated than that.

And the fact that Sewell did not submit his “paper” to the most appropriate journal – namely, Physical Review Letters (the go-to journal for the most important announcements in physics) – this fact alone reveals either complete naiveté on the part of Sewell or, more likely, the typical sleazy tactics ID/creationists have been using for nearly 50 years now.

I would say that the “nuisance payoff” to Sewell’s lawyers is well worth the exposure of Sewell’s tactics along with the fact that ID/creationists continue to play this game despite decades of being repeatedly refuted and rebuffed by the scientific community.

P.S. Would there be any advantage to reposting and having available on a suitable thread the example I posted recently over on the Bathroom Wall? I could easily repost it.

SWT said: I just took a look back at Mark Perakh's excellent essay and was greatly amused by the first comment.

mrg said: And so the blatantly stoopid SLOT argument has been largely supplanted by the glib gibberish of the "conservation of information" argument -- though it's nothing more than a shapeshifted version of the SLOT argument.

… We obtain the equation ∫dQ/T = S - S₀ which, while somewhat differently arranged, is the same as that which was formerly used to determine S. If we wish to designate S by a proper name we can say of it that it is the transformation content of the body, in the same way that we say of the quantity U that it is the heat and work content of the body. However, since I think it is better to take the names of such quantities as these, which are important for science, from the ancient languages, so that they can be introduced without change into all the modern languages, I propose to name the magnitude S the entropy of the body, from the Greek word η τροπη, a transformation. I have intentionally formed the word entropy so as to be as similar as possible to the word energy, since both these quantities, which are to be known by these names, are so nearly related to each other in their physical significance that a certain similarity in their names seemed to me advantageous. …

The very terms themselves express contradictory concepts. The word "evolution" is of course derived from a Latin word meaning "out-rolling". The picture is of an outward-progressing spiral, an unrolling from an infinitesimal beginning through ever broadening circles, until finally all reality is embraced within. "Entropy," on the other hand, means literally "in-turning." It is derived from the two Greek words en (meaning "in") and trope (meaning "turning"). The concept is of something spiraling inward upon itself, exactly the opposite concept to "evolution." Evolution is change outward and upward, entropy is change inward and downward.

And, of course, the comments over at Unimaginably Dense never cease to amaze. Those comments following Sewell’s whining are just as “remarkable.”

Sewell clearly doesn’t know anything about the editor at the American Journal of Physics; but I can assure anyone here that this editor is not fooled by any of Sewell’s dopy “arguments.”

Mike Elzinga said: On the other hand, here is Henry Morris’ pseudo-scholarship back in 1973.

The very terms themselves express contradictory concepts. The word "evolution" is of course derived from a Latin word meaning "out-rolling". The picture is of an outward-progressing spiral, an unrolling from an infinitesimal beginning through ever broadening circles, until finally all reality is embraced within. "Entropy," on the other hand, means literally "in-turning." It is derived from the two Greek words en (meaning "in") and trope (meaning "turning"). The concept is of something spiraling inward upon itself, exactly the opposite concept to "evolution." Evolution is change outward and upward, entropy is change inward and downward.

386sx said:

Mike Elzinga said: On the other hand, here is Henry Morris’ pseudo-scholarship back in 1973.

The very terms themselves express contradictory concepts. The word "evolution" is of course derived from a Latin word meaning "out-rolling". ...

He's completely ignorant of the real etymology, but even his wrong etymology is just bizarre, what with the weird "out-rolling" and "in-turning" phrases he uses. And besides that, using etymology of words to disprove a scientific theory is about as cheesy as scholarship (read: hucksterism) can get. Lol.

Of course, it is the very entry into the biosphere of radiation from the sun that makes life, and its evolution, possible! In my posts I had fun with this, pointing out that Sewell’s “proof” also showed that weeds can’t grow, and neither can flowers.

Typical creationist "response".

To point out what should be obvious, even to a creationist:

What you say has nothing to do with the 2nd law of thermodynamics.

You have no response, so you change the subject.

But, let us just pause a moment, and ask what the creationist explanation is for the issues that you bring up? That the "intelligent designer(s)" just wanted it that way?

Why is the Earth round? Because that's the way that the ID wanted it? Why is the Earth flat? Because that's the way that the ID wanted it? Why is the Earth shaped like a pretzel, or like a "Penrose triangle", or why is there no Earth at all? Because that's the way that the ID wanted it? After all, can't "intelligent designers" do whatever they want, and we are in no place to question their motives?

Joe Felsenstein said:

386sx said:

Mike Elzinga said: On the other hand, here is Henry Morris’ pseudo-scholarship back in 1973.

The very terms themselves express contradictory concepts. The word "evolution" is of course derived from a Latin word meaning "out-rolling". ...

He's completely ignorant of the real etymology, but even his wrong etymology is just bizarre, what with the weird "out-rolling" and "in-turning" phrases he uses. And besides that, using etymology of words to disprove a scientific theory is about as cheesy as scholarship (read: hucksterism) can get. Lol.

Morris was actually correct about the word "evolution", see here, though of course that the name "evolution" came from an inappropriate Victorian metaphor is not an argument against it.

In 18th century biology, "evolution" referred to the appearance of the features of the embryo from their preformed state.

Steve P. said:

Of course, it is the very entry into the biosphere of radiation from the sun that makes life, and its evolution, possible! In my posts I had fun with this, pointing out that Sewell’s “proof” also showed that weeds can’t grow, and neither can flowers.

Er, Prof. Felsenstein, radiation burns the skin. It causes cancer. Bad news for a lot of organisms. Now how do you suppose early life was able to somehow develop a way to filter out the debilitating effects of bad light while simultaneously utilizing the good wavelengths? Seems they would have to figure out how to block the bad before being able to use the good light. Is there an emergent answer to this conundrum in here somewhere?

TomS said: In 18th century biology, "evolution" referred to the appearance of the features of the embryo from their preformed state.

If I were king, “out-rolling” and “in-turning” would outlawed because they just look bizarro. They just rub me the wrong way for some reason. I will have nightmares for a long time after having seen those "words". :P

(This creationist argument also rests upon the misconception that evolution acts always to produce more complex organisms. In fact evolution acts to produce more highly adapted organisms, which might or might not be more complex than their ancestors, depending upon their environment. For example, most cave organisms and parasites are qualitatively simpler than their ancestors. This biological misconception will not be discussed in this article.)

Why is Sewell focusing on evolution? If his view of thermodynamics is correct, it seems to me that life as we know it wouldn't be possible, at least not without Sewell's god propping up every metabolism there is. But this has always confused me. If life itself is possible, evolution does nothing more than shuffle organic molecules around. Sewell seems to be tilting at the wrong windmill here. He should be arguing that LIFE is not possible.

Using the 2nd law as an argument against evolution is arguing that life isn't possible. It's just that the users of that argument don't seem to realize that, even when it is explicitly pointed out to them.

I find it an interesting exercise when coming across an argument against evolution to check whether the argument is at least as relevant when formulated as an argument against reproduction and development. (Or against "micro"evolution within "kinds", which so many of the evolution deniers insist that they accept, but it's not as amusing to see the results.) From "teach all sides" to "irreducible complexity". From "if X is true, then we cannot trust our knowledge" to "I believe that I have a special relationship with my Creator".
And "the 2nd law of thermodynamics".

TomS said: I find it an interesting exercise when coming across an argument against evolution to check whether the argument is at least as relevant when formulated as an argument against reproduction and development.

phantomreader42 said: ID is nothing more than the child's story of a magical baby-delivering stork, retold in the idiom of information theory.

I tossed the Atheistoclast derail to the BW. Sorry, folks.

Richard B. Hoppe said: I tossed the Atheistoclast derail to the BW. Sorry, folks.

Richard B. Hoppe said: I tossed the Atheistoclast derail to the BW. Sorry, folks.

Richard B. Hoppe said: I tossed the Atheistoclast derail to the BW. Sorry, folks.

SWT said:

Henry J said: Why is it always the second law? Why not the first or third? (Or fourth if there's that many.)

The second law

Talks about how systems change in time

Is couched in terms of a quantity few lay people actually understand

Is easily misrepresented because of an unfortunate nomenclature choice by the founders of information theory

Is easily misrepresented because of the statistical nature of the Boltzmann interpretation and the difficulty of explaing that interpretation to lay people (especially innumerate lay people)

That's why. (At least IMNSHO.)

TomS said: Typical creationist "response". To point out what should be obvious, even to a creationist: What you say has nothing to do with the 2nd law of thermodynamics. You have no response, so you change the subject. But, let us just pause a moment, and ask what the creationist explanation is for the issues that you bring up? That the "intelligent designer(s)" just wanted it that way? Why is the Earth round? Because that's the way that the ID wanted it? Why is the Earth flat? Because that's the way that the ID wanted it? Why is the Earth shaped like a pretzel, or like a "Penrose triangle", or why is there no Earth at all? Because that's the way that the ID wanted it? After all, can't "intelligent designers" do whatever they want, and we are in no place to question their motives?

Steve P. said: As to creationists response for why life can use light from the sun but not rocks? Good question. Life obviously contains something rocks don’t. Dembski proposes active information.

I'm not a design denier. I believe in microdesign. You deny macrodesign when you deny that rocks are designed.

Steve P. said: Evolution, promoted here on PT as a creative force would certainly defy the SLOT.

Fortunately, we know better. Evolutionary processes are stop-gap measures, maintaining what already exists, but alas slowly losing the battle.

So to Joe's quip that duh, life just so happens to be able to utilize light from the sun, therefore Sewell is wrong, wrong, wrong, is rather er infantile.

(heat flux)*(driving force for heat conduction) + (flux of component 1)*(driving force for diffusion of component 1) + ... (flux of component nc)*(driving force for diffusion of component nc) + (momemtum flux)*(driving force for momentum transfer) + (reaction rate 1)*(driving force for reaction 1) + ... (reaction rate nr)*(driving force for reaction nr)

Richard B. Hoppe said: I tossed the Atheistoclast derail to the BW. Sorry, folks.

SWT said: Prove it. Be sure to use math.

Steve P. said: Evolution, promoted here on PT as a creative force would certainly defy the SLOT.

Fortunately, we know better. Evolutionary processes are stop-gap measures, maintaining what already exists, but alas slowly losing the battle.

To be sure, we are trying to quantify in ‘scientifically innovative ways’ just what makes life different from rocks. You (pl) in turn simply say ‘its all physics and chemistry so why do you bother looking elsewhere’. Stark contrast, no?

“ID waxing, ND waning”.

Airplanes can violate the "law of gravity" because they are intelligently designed.

And that proves that birds are intelligently designed, too.

Steve P wrote:

"Fortunately, we know better. Evolutionary processes are stop-gap measures, maintaining what already exists, but alas slowly losing the battle."

Well as long as "we" are so smart and knowledgable, perhaps "we" wouldn't mind answering a few questions. Complete with references from the scientific literature of course, not just hand waving made-up mumbo jumbo.

1) How many species of living organisms are currently alive on the earth? How many were alive six hundred million years ago?

2) How many genera of living organisms are currently alive on the earth? How many were alive six hundred million years ago?

3) How many families of living organisms are currently alive on the earth? How many were alive six hundred million years ago?

4) How many phyla of living organisms are currently alive on the earth? How many were alive six hundred million years ago?

Now once you have answered those questions honestly, I think you will see that your "hypothesis" is conclusively falsified. But then again, you still don't believe that competition is real now do you?

And of course as MIke has pointed out, intelligence does NOT violate the SLOT, neither does intelligent design, neither does life. You got nothin Poindexter.

TomS said: Airplanes can violate the "law of gravity" because they are intelligently designed. And that proves that birds are intelligently designed, too.

NOTHING “defies” the laws of thermodynamics; PERIOD.

TomS said: Airplanes can violate the "law of gravity" because they are intelligently designed.

bigdakine said: 1. There's no free lunch 2. You can't get it wholesale.. 3. You must pay tax.

mrg said:

NOTHING “defies” the laws of thermodynamics; PERIOD.

Tech question, entropy of mixing ... from what Lambert says, it's basically the same as dispersal of a gas into a vacuum. In the dispersal of a gas in a vacuum, the concentration of energy of the molecules in a small vessel is dispersed by expanding into the larger (empty) vessel.

Same thing with mixing, but it involves two or more substances dispersing into each other.

This is not the same as shuffling a deck of cards, which despite old-fashioned examples doesn’t represent a change in entropy. But what about dispersal of salt and pepper into each other? I don’t think it does, but I can’t get my little brain clearly wrapped around why not.

apokryltaros said:

Richard B. Hoppe said: I tossed the Atheistoclast derail to the BW. Sorry, folks.

While you're at it, can we toss Steve P into the BW, too?

Richard B. Hoppe said: They make SteveP's ignorant comments worth keeping.

I get exasperated when creationists imply us science geeks are refusing to accept that we’re off base.

Henry J said: But that's what their whole "argument" amounts to.

Mike Elzinga said: Adiabatic, free expansion of an ideal gas into a vacuum does no work. No energy enters, no energy leaves. The kinetic energies of all the molecules remain the same as they were before; i.e., the distribution of energy over all microscopic states (translational kinetic energies) remains constant. So the entropy remains constant.

When molecules are allowed to expand into a larger volume (in three-dimensional space) , quantum mechanics shows that an interesting change in possible energy levels takes place: the energy levels become closer together. (Technically, we must say that the density of occupiable levels in any selected energy range is greater.) This means effectively that molecules, if allowed to occupy a larger volume even without any increase in their energy, can spread out to occupy many more energy levels. This means greater dispersal of energy and an increase in entropy simply by there being a greater three-dimensional volume in which the molecules can move. (Further, because any change in which entropy increases is a spontaneous change. It happens without any outside aid, energy input, etc.)

It depends on what is mixing and how. If a partition is removed from a container containing identical gases in each half of the container, and if the gases in each half started at the same temperature and pressure, there would be no change in total entropy because the distributions of energy would be the same. And if the gases were identical except for the color of the molecules (green in one half of the container, red in the other), the entropy doesn’t change because the color has nothing to do with the distribution of ENERGY. (note: this is just an illustration; molecules are not “colored.”)

How does that apply to (1), perfume in a room? It spontaneously mixes with the gases in the large room because its energy is redistributed among more energy levels than in the small vapor space of the bottle. This is the same as having greater energy dispersal = an increase in entropy = spontaneity. And (2), cream in coffee? (Or any other kinds of liquids mixing?) Same as above. Because the motional energy in the molecules of the substances in cream can be more spread out between the molecules in the coffee, the energy of the cream, or of any liquid mixing with another, is redistributed among more energy levels in the mixture than alone by itself = greater energy dispersal = increase in entropy = spontaneous mixing.

PS: If entropy is a measure of dispersal of energy, it would seem to me that the spread of energetic molecules from a pressurized chamber into a vacuum would certainly represent a dispersal of energy.

Richard B. Hoppe said:

apokryltaros said:

Richard B. Hoppe said: I tossed the Atheistoclast derail to the BW. Sorry, folks.

While you're at it, can we toss Steve P into the BW, too?

Not when he elicits informative comments like those of SWT and Mike Elzinga just above. They make SteveP's ignorant comments worth keeping.

mrg said: OK, this is what Lambert says:

Thinking in terms of heat engines, according to Carnot a heat engine requires a temperature difference to do work. That’s straightforward, no big deal. But if there’s a temperature gradient, entropy is increasing from a heat transfer whether we extract any work from it or not.

So if we have a pressure gradient, we can in the same way extract work from that – like the old compressed-air torpedoes, a pressurized air bottle driving a turbine or reciprocating motor. It would seem that losing that pressure differential would entail an increase in entropy whether we extract any work from it or not.

It would seem that mixing of energetically indistinguishable particles would involve no change in entropy. However, Lambert again states that there is a change in entropy in mixing even if it involves no change in energy:

Y’know … I don’t feel the slightest bit embarrassed about not following this very well.

mrg said: PS: If entropy is a measure of dispersal of energy, it would seem to me that the spread of energetic molecules from a pressurized chamber into a vacuum would certainly represent a dispersal of energy.

Mike Elzinga said: I’ll need to go read what Lambert says in context; but the part you quote seems out of context or unqualified.

Mike Elzinga said:

mrg said: PS: If entropy is a measure of dispersal of energy, it would seem to me that the spread of energetic molecules from a pressurized chamber into a vacuum would certainly represent a dispersal of energy.

That is a change in energy density. This is not the same as the number of energy microstates.

mrg said: OK, one question though: does spontaneous heat transfer from a system to its environment represent an increase in entropy?

Mike Elzinga said: The amount of energy contained within a specified time interval is referred to as power.

Mike Elzinga said: Yes.

mrg said:

Mike Elzinga said: Yes.

OK, now I'm really confused, because if a system (compressed air vessel) drains into a vacuum environment, the thermal energy represented by the molecular motions is dispersed into its environment just as certainly as the thermal energy of a heated object is thermally transferred to the atmosphere around it.

Guy, if I was that ignorant, I wouldn’t be even able to ask you the questions I am asking.

But you raise an excellent point.

The availability of energy to do work is also connected to energy density. Let those molecules expand into outer space, and we can no longer capture the energy and use it for driving turbines.

But that still has nothing to do with energy states. In order to do work, energy has to “flow downhill” so to speak; from higher kinetic energies to lower because that is the direction the momentum transfers will occur. That depends on temperature differences, hence increases in entropy.

But you can’t get much energy out of a few hundred molecules after the rest get away.

Again, Lambert is telling me what seems to be the exact opposite: that even though there is no change in overall energy, by expanding the volume the available microstates have expanded thereby and so the entropy has increased.

What puzzles me is that by eliminating the pressure difference, even if no work was performed in doing so, we have eliminated the ability of the system to perform work thereby. Also ... there's no way to restore the pressure difference without doing work. Something tells me these two circumstances are addressed by the laws of thermodynamics, but I don't know precisely how.

Y'know, what's really amusing about this conversation is to envision Steve P trying to follow it. He will not understand a word of it. And, in failing to do so, he will still refuse to admit to himself that he has absolutely no understanding of such matters.

mrg said: Again, Lambert is telling me what seems to be the exact opposite: that even though there is no change in overall energy, by expanding the volume the available microstates have expanded thereby and so the entropy has increased. What puzzles me is that by eliminating the pressure difference, even if no work was performed in doing so, we have eliminated the ability of the system to perform work thereby. Also ... there's no way to restore the pressure difference without doing work. Something tells me these two circumstances are addressed by the laws of thermodynamics, but I don't know precisely how.

mrg said: Again, Lambert is telling me what seems to be the exact opposite: that even though there is no change in overall energy, by expanding the volume the available microstates have expanded thereby and so the entropy has increased. What puzzles me is that by eliminating the pressure difference, even if no work was performed in doing so, we have eliminated the ability of the system to perform work thereby. Also ... there's no way to restore the pressure difference without doing work. Something tells me these two circumstances are addressed by the laws of thermodynamics, but I don't know precisely how.

Y’know, what’s really amusing about this conversation is to envision Steve P trying to follow it. He will not understand a word of it. And, in failing to do so, he will still refuse to admit to himself that he has absolutely no understanding of such matters.

Eric Finn said: The pressure difference... Each of the atoms of the ideal gas still has the same energy as initially. Surely they can do work, if you let them escape the container and collide against something.

mrg said:

Eric Finn said: The pressure difference... Each of the atoms of the ideal gas still has the same energy as initially. Surely they can do work, if you let them escape the container and collide against something.

Sure, if you have yet another exterior system at lower pressure, allowing them to expand a piston or drive a turbine or whatever. But the pressure difference between the original cylinder and its immediate environment is gone; and so we cannot use the original pressure difference to do any work, 'coz it ain't there no more.

I'll sit on this for a while. I don't feel like I've really resolved my confusions on the matter, but I don't think I'll do more than go in circles if I persist. Something to go to the back of my mind for consideration over the coming years.

On my JFK assassination studies I've been trying to track the paper trail of his ownership of the rifle. That's at least as much of a headache as trying to figure out thermodynamics -- with misrepresentations of the facts playing a large part in the difficulty. One headache at a time.

Mike Elzinga said: So far he hasn’t tried to pull FL’s attempt at copy/paste gotchas. That incident over on the BW was FL’s final waterloo. Good riddance.

Eric Finn said: I think Professor Frank Lambert is right. According to the quantum mechanics, the density of states is higher in a big volume than in a small volume. One of the experimentally verified examples is the Casimir effect.

Mike Elzinga said: So the energy of the particle remains constant if no work is done on or by the particle when changing the dimensions of the box. So the distribution of energy among all particles remains constant if the particles do no work when adiabatically expanding into a larger box.

I think a quick classical analysis shows that Lambert is correct.

We have a sample of an ideal gas expanding adiabatically from volume V₁ to V₂ but doing no work during the expansion. The first law tells us that, for a closed system, the internal energy, U, is related to the heat added to the system, Q, and the work done by the system, W, through the equation

dU = δQ - δW

Also, the internal energy is related to the entropy and volume through the property relationship

dU = TdS - PdV

Since the process is adiabatic and does no work, the first law tells us there is no change in internal energy, so

TdS = PdV

Substituting the ideal gas law (PV=RT) into this equation gives us

dS = (P/T)dV = (R/V)dV = R d(ln V)

Integrating, ΔS = R ln(V₂/V₁)

So, ΔS > 0 if V₂ > V₁

This result makes sense to me, since the process is spontaneous and the calculated ΔA < 0.

SWT said: TdS = PdV Substituting the ideal gas law (PV=RT) into this equation gives us dS = (P/T)dV = (R/V)dV = R d(ln V) Integrating, ΔS = R ln(V₂/V₁) So, ΔS > 0 if V₂ > V₁ This result makes sense to me, since the process is spontaneous and the calculated ΔA < 0.

Eric. SWT and Lambert have it right. The number of accessible microstates increase with volume increase for quantum reasons. Mike is struggling with the Gibbs paradox.

Distinction must be made between reversible and irreversible adiabatic processes. This is not a reversible process.

From a classical point of view, this is rather subtle. Although an irreversible adiabatic process has Q = 0 and W = 0 and Q+W = 0, resist the temptation to say dQ = 0 hence dS = 0. Remember, Q and W are not functions of state - only the sum is, and entropy is a state function.
The reversible isothermal process with the same two endpoints for which the entropy change can be calculated has Q+W = 0 also, although Q = -W > 0.
So from dS = dQ_rev/T, ∆S = n R ln(V_f/V_i)
which must be the case for the irreversible adiabatic case too. That is Lambert's point.

Mike Elzinga said: It depends on what is mixing and how. If a partition is removed from a container containing identical gases in each half of the container, and if the gases in each half started at the same temperature and pressure, there would be no change in total entropy because the distributions of energy would be the same. And if the gases were identical except for the color of the molecules (green in one half of the container, red in the other), the entropy doesn’t change because the color has nothing to do with the distribution of ENERGY.

mrg said: Y'know, what's really amusing about this conversation is to envision Steve P trying to follow it. He will not understand a word of it. And, in failing to do so, he will still refuse to admit to himself that he has absolutely no understanding of such matters.

"No" is meant to refer to Mike's second paragraph.

(Well, I can't fix my ID. Like the ideal gas molecules, I (John_K) am indistinguishable from myself (https://www.google.com/accounts/o8/id?id=blahblah) but if not this must somehow be actually demonstrated using energy, and that is key to understanding irreversibility and entropy.)

--JohnK

Mike Elzinga said:

SWT said: TdS = PdV Substituting the ideal gas law (PV=RT) into this equation gives us dS = (P/T)dV = (R/V)dV = R d(ln V) Integrating, ΔS = R ln(V₂/V₁) So, ΔS > 0 if V₂ > V₁ This result makes sense to me, since the process is spontaneous and the calculated ΔA < 0.

But δW = 0 and δQ = 0 (no work is being done and the process is adiabatic); therefore d(PV) = 0, i.e., PV remains constant, which also means – through PV = nRT - that T is constant. The internal energy of an idea gas depends only on its temperature (U = (3/2)N k_B T). So the internal energy U remains constant. The kinetic energies of an ideal gas do not depend on the separations among the molecules (an ideal gas has no molecular interactions).

dQ = TdS = 0.

… The example you are showing is for a gas undergoing expansion and doing work, but with just enough heat being added to keep the temperature constant and do work as the gas expands; thus keeping the internal energy U constant (dU = 0). This is the isothermal (not adiabatic) example of an ideal gas expanding and doing work. Then, yes, TdS = PdV as you calculated.

Yeah, I keep thinking that from my understanding of what entropy is all about -- energy dispersion -- the escape of a gas from a vessel into evacuated surroundings involves an increase in entropy whether any work is extracted from it or not. I was under the impression that entropy was about "availability" of energy for work, and lose availability, you get more entropy. Energy conservation considerations are for the first law, not the second.

And from the Clausius equation -- heat transfer VS absolute temperature is entropy -- it would seem that the thermal energy in the molecules in the vessel is being transferred by simple dispersion into the environment.

Think of Maxwell's Demon. If MaxDee accumulates active molecules, depleting them from the environment and partially evacuating it, he's reduced entropy -- which the SLOT says he can't do, at least not for free. But if MaxDee lets the molecules out again, doesn't that mean he's undone his reduction of entropy (that is, increased it again?)

My problem is that I'm in the position of exercising intuition on something I know I don't understand. "But if you don't understand it, what valid intuition can you have on it?" Playing hunches only really works for experts.

And then, if we get to a stopping point on this, on to the entropy of mixing, which is what I really want to know about: "If you mix gases or liquids together, you get an increase in entropy."

"But what about mixing salt and pepper?"

"No."

"OK, I'm confused." But one nightmare at a time.

TomS said: Any discussion which involves stuff like calculus which a majority of people can't understand can give the impression that creationism touches on some deep and complicated science.

(Well, I can’t fix my ID. Like the ideal gas molecules, I (John_K) am indistinguishable from myself (https://www.google.com/accounts/o8/id?id=blahblah) but if not this must somehow be actually demonstrated using energy, and that is key to understanding irreversibility and entropy.) –JohnK

Think of Maxwell’s Demon. …

mrg said: "OK, I'm confused." But one nightmare at a time.

Eric. SWT and Lambert have it right. The number of accessible microstates increase with volume increase for quantum reasons. Mike is struggling with the Gibbs paradox.

Mike Elzinga said:

mrg said: "OK, I'm confused." But one nightmare at a time.

I wouldn’t be too concerned about idealized problems like free expansion of an ideal gas or some of the other “gedanken experiments” used to clarify concepts. Those are mostly for making sure students have concepts straight and are not conflating concepts. They are not achievable in reality (or at least they are so difficult experimentally that one finds better ways to do the experiment).

Eric Finn said: On the other hand, I understand mrg's confusion. One source says that the entropy increases (by a known amount) and another source says it stays the same. Both sources base their interpretations on valid principles.

mrg said: I've been poking around on various online sources -- UCDavis ChemWiki for example. They overwhelmingly say that free expansion of a gas into a vacuum leads to an increase in entropy. (It might be noted that Frank Lambert wrote or co-wrote a goodly number of these pages.) I'm going to poke around on this in the town library as well.

Eric Finn said: I might be interested in reading your notes.

mrg said:

Eric Finn said: I might be interested in reading your notes.

Not for release, private scratchups only. I'm sure that they'll migrate into my elementary classical physics writeup: http://www.vectorsite.net/tpecp.html

The Universe may be running out of free energy, but it is not slowly falling apart. On the basis of a simple-minded interpretation of the Second Law, we couldn't imagine a Universe that amounted to much more than it did at the beginning, a dispersed thin fog of hydrogen with traces of helium evenly distributed throughout space. In reality, heavier elements were synthesized by natural processes from lighter ones; stars and planets were formed from the elements, making up intricate stellar and planetary systems; elaborate molecules and crystals arose on the planets, with the planets also developing surface features like mountains and oceans, as well as complex weather patterns. While some critics of modern evolutionary science claim the Second Law rules out the spontaneous emergence of life and its subsequent evolution, there's nothing in the law that implies any such thing.

Physicists understand that the spontaneous emergence of various forms of order observed in nature doesn't mesh neatly with the Second Law, and have puzzled over theoretical means of reconciling the matter -- with some, for example, defining what they call "emergent systems" or various concepts of new laws of thermodynamics to cover this uncertain ground, though not everyone has been impressed by their work. In the meantime, it should be realized that any reference to entropy as "disorder" is simply bogus.

mrg said:

Eric Finn said: On the other hand, I understand mrg's confusion. One source says that the entropy increases (by a known amount) and another source says it stays the same. Both sources base their interpretations on valid principles.

I've been poking around on various online sources -- UCDavis ChemWiki for example. They overwhelmingly say that free expansion of a gas into a vacuum leads to an increase in entropy. (It might be noted that Frank Lambert wrote or co-wrote a goodly number of these pages.) I'm going to poke around on this in the town library as well. One element of confusion they point out is that while the spatial translation of molecules doesn't factor into entropy, the thermal energy in the molecules being translated does, amounting to a heat flow across a system boundary. But it is my plan to go through the various ChemWiki pages and write up a set of notes to see if I can make sense of them. I don't believe that I'm going to get anywhere with further discussion here. So far, I feel I know less than I did when I started.

It occurs to me - especially in order to head off any discouragement I may have caused mrg - that I should add an important point about that problem as handled by classical thermodynamics.

The power of classical thermodynamics lies in the fact that one can empirically compute all sorts of things about thermodynamic systems without having to know any of the microscopic details. Lots of messy stuff lies hidden, and presumably accounted for phenomenologically in the calculations.

But not knowing the microscopic details is also a major weakness; hence statistical mechanics, quantum mechanics, and quantum field theory, etc..

So one can tentatively accept the results of classical thermodynamics regarding what it says about entropy in the case of free expansion. But what it means for entropy to be a state variable is very murky and needs that deeper analysis.

If classical thermodynamics is right, then ultimately a detailed microscopic analysis and experimental verification will show it.

And as long as there are paradoxes between classical thermodynamics and those deeper analyses, one has the excruciating job of clarifying and sorting concepts as well as making sure the underlying physical description of the problem really represents reality.

We are already well passed that with regard to thermodynamics and statistical mechanics; but, as the deeper analyses show, most of these “simple” problems are, in reality, extremely complex and subtle.

But that’s how we learn.

I think that sounds along the line of a comment I made in my physics tutorial: that the combined gas law works fine and a casual student of the subject has no need to know much more than that. But if it wasn't for Maxwell-Boltzmann statistics, there'd be no way to hook up the combined gas law to basic mechanical principles, it would just be an ad-hoc rule of thumb.

I suppose it's also in a way like Maxwell's equations. Few EEs honestly need to know them, in fact the heart of practical EE is Ohm's Law. But Ohm's Law only exists as a practical manifestation of Maxwell's equations.

mrg said: I suppose it's also in a way like Maxwell's equations. Few EEs honestly need to know them, in fact the heart of practical EE is Ohm's Law. But Ohm's Law only exists as a practical manifestation of Maxwell's equations.

Mike Elzinga said: It has an underlying microscopic basis, but one need not know that in order to work EE problems.

mrg said: Well, at a EE level the practical reality is similar to what I once heard said about plumbers: "All you gotta know is that water runs downhill and payday's Friday."

mrg said:

Eric Finn said: I might be interested in reading your notes.

Not for release, private scratchups only. I'm sure that they'll migrate into my elementary classical physics writeup: http://www.vectorsite.net/tpecp.html -- but it may not be as more than a few paragraphs or changes. I don't think the thermo stuff in it is wrong by any means, but that's because I got to the point where I simply threw everything out I wasn't certain of. Not very satisfactory, so I am wondering what I can do to improve matters. I have gone through some very laborious studies to resolve questions at times -- the work only ending up being a paragraph in a release document. But it has to be the RIGHT paragraph.

Eric Finn said: A follow-up question might be: “How did the ideal gas acquire an energy distribution that can be described by common temperature?”. It seems to me that it is correct to state that ideal gas (that can be described by common temperature) in a large volume has higher entropy than ideal gas (than can be described by the same common temperature) in a small volume, even though the number of particles is the same in these two situations. Further, it seems to me that the large-volume case can not (easily) be acquired from the small-volume case by means of simple free expansion of ideal gas.

Mike Elzinga said:

Eric Finn said: A follow-up question might be: “How did the ideal gas acquire an energy distribution that can be described by common temperature?”. It seems to me that it is correct to state that ideal gas (that can be described by common temperature) in a large volume has higher entropy than ideal gas (than can be described by the same common temperature) in a small volume, even though the number of particles is the same in these two situations. Further, it seems to me that the large-volume case can not (easily) be acquired from the small-volume case by means of simple free expansion of ideal gas.

In many textbooks on classical thermodynamics, authors try to be careful to distinguish between reversible and irreversible processes. And an attempt is made to establish entropy as a state variable, meaning that the value of such a variable depends only the particular state of a system and not how the system got into that state. These sections of most thermodynamics textbooks have generally caused much puzzlement, pain, and misconceptions because they often come too early in a student’s development, and mathematical skill is still in a hazy state of development.

I still think these kinds of discussions have to take place with not only physics students, but with the non-majors and the general public as well. But I no longer think I know how to do it in a book for lay audiences.

Eric Finn said: It may appear that I failed to appreciate the fact that entropy is a state variable, and does not depend on how the system got into that state. I was merely seconding your notion that a system without interactions can not change its energy distribution.

Eric Finn said: I think you are doing well. The concept of entropy in physics is formulated in the language of mathematics. It is by no means easy to translate the concept of entropy into a language that lacks well-defined meanings for words. And the task is not made any easier, when a set of people try deliberately to mangle the words even more.

In reflecting on this discussion, Mark Chu-Carroll's mantra came to mind: the worst math is no math. (He write the Good Math, Bad Math blog.) You can make verbal arguments about thermodynamics all day, but to demonstrate a point rigorously, you've got to do the math. (In our toy problem about the entropy change for isothermal expansion of an ideal gas, the ultimate resolution is to do the statistical calculation of the entropy of the gas at the initial and final conditions.)

This is how Sewell's argument goes off the rails; he throws up a few equations, but doesn't -- in a math journal! -- do the additional mathematical development to demonstrate his point, instead resorting to verbal hand-waving that leads him to an incorrect conclusion.

Mike makes an excellent point above about state functions, reversible paths, and equivalent paths -- if students don't understand these concepts, they can't really do thermodynamics properly. IMO, this is compounded by the fact that entropy is a far more abstract mathematical construct than internal energy or enthalpy, which students find easier to relate to their experience.

TomS said:

Eric Finn said: I think you are doing well. The concept of entropy in physics is formulated in the language of mathematics. It is by no means easy to translate the concept of entropy into a language that lacks well-defined meanings for words. And the task is not made any easier, when a set of people try deliberately to mangle the words even more.

I agree. The advocates of evolution denial are aware that any rhetoric which elicits responses using mathematics is a victory for them. The solution, IMHO, is to give a response which involves no mathematics. Don't take the bait.

First law of technical writing: "A workable, easily understood simplification is vastly more useful than the complete, incomprehensible truth."

Associated with this is the concept of "fog factor", numerically ranked in the number of years of specialized education required to understand the argument.

One of the truisms about that is that if an argument can only be understood by people with a high enough level of fog factor, it isn't generally an argument of interest to anyone except those with the same level of fog
factor.

I'm going through object-oriented programming concepts right now. I've never understood it well, and the more I look into it I find that it seems to a considerable if not complete extent the product of people who don't want to make themselves understood. What's particularly obnoxious is that they use a common set of terms for which they have no mutually agreed-upon set of tidy definitions.

"There are thousands of computer languages, but the vast majority are only used by the people who invented them."

SWT said: This is how Sewell's argument goes off the rails; he throws up a few equations, but doesn't -- in a math journal! -- do the additional mathematical development to demonstrate his point, instead resorting to verbal hand-waving that leads him to an incorrect conclusion.

Mike Elzinga said: And to get miffed about it and complain on a creationist website about being “expelled” or discriminated against; this has to be related to some kind of mental illness or to just plain malicious bitterness about the fact that there are such things as cops and experts.

Yeah, whining if any should be done in private.

Maybe with cheese on the side.

Or something like that.

Henry J said: Yeah, whining if any should be done in private. Maybe with cheese on the side. Or something like that.

I was trying to remember one of the other issues involving the entropy change of an ideal gas, and it came to me in the car while returning from a trip today.

SWT presented the solution to the entropy change of a free expanding ideal gas by substituting the isothermal and reversible expansion between the initial and final volumes.

If entropy is a state function, shouldn’t that be ok? Well, as it turns out, there is another wrinkle in this “recipe.”

The change in entropy, which is the integral of dQ/T between states A and B of a thermodynamic system is often shown to be

S(B) - S(A) ≥ ∫_A^B dQ/T

with the equal sign applying to the reversible path from A to B.

So shouldn’t the free expansion, which is irreversible, produce a greater change in entropy?

Over the years there has been a better cataloguing of misconceptions and pitfalls in learning concepts of physics. These include things in very basic physics, such as Newton’s third law where students are asked the tension in a rope when a force F is applied to each end of the rope (as in a tug-of-war). There are literally dozens of catalogued misconceptions that have been identified, studied, and addressed.

But I have not seen very much of this kind of work done with the concepts in thermodynamics and statistical mechanics. I think many physics instructors have been aware of the confusion cause by equating entropy with disorder. The issues of reversible versus irreversible transitions between states are also familiar.

The typical approach to these kinds of misconceptions is to raise these issues if the students don’t (and they usually don’t). And one raises them by posing questions and raising issues or “counterexamples” that lead to paradoxes. It is good pedagogical practice to get these kinds of thought process going in order to make sure that concepts are ironed out and understood by the students.

And this is precisely why ID/creationism should NOT be given any time in the public school science classroom. ID/creationism is deliberately concocted sectarian pseudo-science that begins by misrepresenting science.

It is difficult enough to get the right concepts clear in the minds of students without also having to grapple with a blizzard of garbage deliberately designed to prop up sectarian dogma and therefore conflict with reality.

Mike Elzinga said:

Eric Finn said: I think Professor Frank Lambert is right. According to the quantum mechanics, the density of states is higher in a big volume than in a small volume. One of the experimentally verified examples is the Casimir effect.

Again, the discussion over there is incomplete. The energy of a quantum mechanical particle in a box is ε = (h²/8m)(n_x²/L_x² + n_y²/L_y² + n_z²/L_z²), where h is Planck’s constant and m is the mass of the particle. Doubling each of the dimensions L_j also doubles the number of n_j’s if the particle retains the same translational kinetic energy. So the energy of the particle remains constant if no work is done on or by the particle when changing the dimensions of the box. So the distribution of energy among all particles remains constant if the particles do no work when adiabatically expanding into a larger box. Again we have to distinguish between energy density and density of states. Simply expanding the volume into which a particle moves, without changing the kinetic energy of the particle, is exactly what we mean by adiabatic free expansion. No change in particle energies, no net change in energy microstates. Only a change in energy density, not density of microstates.

No change in particle energies, no net change in energy microstates. Only a change in energy density, not density of microstates.

No change in particle energies, no net change in total energy. Only a change in energy density, and number of microstates.

It appears that Granville Sewell must still be really tweaked about having his paper rejected. It’s now July 29, 2011, and he just can’t accept the fact that he is wrong.

I thought I was wrong once.

But it turned out I was mistaken.