Entropy is NOT disorder (it really is not)

[Guy Threepwood]

Common English word usage has little to do with science which is universal and not beholden to any language or culture.

Build a sandcastle on the beach Sayak, then sit back and watch, and it will empirically demonstrate entropy for you, every time, that's a repeatable observable measurable phenomena, and is used to reliably make all kinds of useful determinations and predictions

If that's not 'scientific' then that supports my point; that whether or not something is 'scientific' is entirely semantic and of little use, I'm more interested in what's actually true..

 

[sayak83]

Build a sandcastle on the beach Sayak, then sit back and watch, and it will empirically demonstrate entropy for you, every time, that's a repeatable observable measurable phenomena, and is used to reliably make all kinds of useful determinations and predictions

If that's not 'scientific' then that supports my point; that whether or not something is 'scientific' is entirely semantic and of little use, I'm more interested in what's actually true..

The second law does not apply to sandcastles. The entropy of a heap of sand and a sandcastle is the Same according to the mathematics that determines what entropy means.

Science is about generalizability. Since there exists systems that spontaneously increase in order (crystals, turbulence etc.) and systems that spontaneously loose order (like the sandcastle). There is no law regarding decrease or increase of order in the world and each system has to be analyzed case by case.

 

[Skwim]

No. I am saying that when discussing science one should stick with how science defines it rather than how it's used in any language.

Agreed.

Since the debate here is whether it's proper to connect the scientific property entropy with the concept of order and disorder, quoting an English language dictionary does not help.

Unless that entry happens to be scientifically correct. Correct?

.

 

[Guy Threepwood]

The second law does not apply to sandcastles. The entropy of a heap of sand and a sandcastle is the Same according to the mathematics that determines what entropy means.

Science is about generalizability. Since there exists systems that spontaneously increase in order (crystals, turbulence etc.) and systems that spontaneously loose order (like the sandcastle). There is no law regarding decrease or increase of order in the world and each system has to be analyzed case by case.

exactly, two different phenomena, semantics aside.

The sandcastle is beyond doubt observable decay, tendency towards disorder- 'scientific' or not, it's unambiguously true-

It's debatable though that crystals are really tending towards more order beyond a superficial observation, since as they are underwritten by MORE complex systems. Crystals do not self-generate the finely tuned instructions for their own creation

Similarly a self extracting software application- superficially 'self organizes' but not without instructions determining how to do so.

While software, weather systems, and crystals can all decay into disorder when faced with the more empirical /definitive form of entropy: decay

 

[sayak83]

exactly, two different phenomena, semantics aside.

The sandcastle is beyond doubt observable decay, tendency towards disorder- 'scientific' or not, it's unambiguously true-

It's debatable though that crystals are really tending towards more order beyond a superficial observation, since as they are underwritten by MORE complex systems. Crystals do not self-generate the finely tuned instructions for their own creation

Similarly a self extracting software application- superficially 'self organizes' but not without instructions determining how to do so.

While software, weather systems, and crystals can all decay into disorder when faced with the more empirical /definitive form of entropy: decay

It's also unambiguously true that this same sand again gets piled up into vast sand dunes with complex structure, which gets compacted in sandstone of ever more complex order. So it's not all clear that order of a pile of sand is decreasing at all with time. It's increasing. So emperical science refutes you... again

 

[Guy Threepwood]

It's also unambiguously true that this same sand again gets piled up into vast sand dunes with complex structure, which gets compacted in sandstone of ever more complex order. So it's not all clear that order of a pile of sand is decreasing at all with time. It's increasing. So emperical science refutes you... again

[Hoyle] found the idea that the universe had a beginning to be pseudoscience, resembling arguments for a creator, "for it's an irrational process, and can't be described in scientific terms"

Similarly, you are saying that the natural tenancy towards decay, collapse, disorder of the sandcastle cannot be described in scientific terms.

Then obviously 'scientific terms' are not the best way to determine reality, for those of us who are curious about that sort of thing

 

[sayak83]

Agreed.


Unless that entry happens to be scientifically correct. Correct?

.

Yes. Correct. When in doubt it's always better to look at the technical manuals of the field to ensure accuracy.
But here I am not denying that many scientists have linked entropy with disorder. I am stating that the link is not appropriate to make and one should not get carried away with how the evolution of a jar of gas molecules do conform to this intuition as many other systems do not. The dissent is coming from chemists, fluid mechanics and scientists who work with complex non_isotropic systems because the examples of increasing order and phenomenologically rich complexity along with increasing entropy are blatantly frequent there.

 

[sayak83]

[Hoyle] found the idea that the universe had a beginning to be pseudoscience, resembling arguments for a creator, "for it's an irrational process, and can't be described in scientific terms"

Similarly, you are saying that the natural tenancy towards decay, collapse, disorder of the sandcastle cannot be described in scientific terms.

Then obviously 'scientific terms' are not the best way to determine reality, for those of us who are curious about that sort of thing

It can be described in scientific terms, but it cannot be generalized into some universal propensity to greater disorder as that is False. The sand will regain complexity and order as it gets incorporated into vast sand dunes and then into we'll ordered sand stone. There is no law of ever increasing disorder as Nature has no such inclination . Sorry.

 

[Guy Threepwood]

It can be described in scientific terms, but it cannot be generalized into some universal propensity to greater disorder as that is False. The sand will regain complexity and order as it gets incorporated into vast sand dunes and then into we'll ordered sand stone. There is no law of ever increasing disorder as Nature has no such inclination . Sorry.

Try it and see, let me know when the wind rebuilds the sandcastle for you, it will honestly - just wait long enough!

 

[sayak83]

Try it and see, let me know when the wind rebuilds the sandcastle for you, it will honestly - just wait long enough!

It will make a sand dune and then a sandstone. Both more ordered than a sandcastle. Nature makes order out of disorder, but the structures of natural order are different than structures of man made order. No less orderly though (waves, dunes, sandstone, clouds, wind, crystals) etc. Basically nature makes the kind of order it wants and not what we want.

 

[Guy Threepwood]

It will make a sand dune and then a sandstone. Both more ordered than a sandcastle.

I get it Sayak, anyone can use 'scientific' semantics to confuse each other about which demonstrates greater order here.


Your confusion lies in introducing the word 'complexity'. Of course a random pile of 100 bricks is a more 'complex' pattern than the same bricks in the wall before it is knocked down. So too with the sand dune or rock resulting from the destroyed, collapsed, decayed sandcastle.

Our own bodies and everything in nature is like the sandcastle, we only delay the ravaging effects of entropy by virtue of tiny nano-machines constantly trying to repair our parts- again according to instructions, literally digitally coded plans in this case

Without a pre-determined plan to follow, unguided nature applies entropy by default, in every instance we see,

sorry bout that!

 

[sayak83]

I get it Sayak, anyone can use 'scientific' semantics to confuse each other about which demonstrates greater order here.


Your confusion lies in introducing the word 'complexity'. Of course a random pile of 100 bricks is a more 'complex' pattern than the same bricks in the wall before it is knocked down. So too with the sand dune or rock resulting from the destroyed, collapsed, decayed sandcastle.

Our own bodies and everything in nature is like the sandcastle, we only delay the ravaging effects of entropy by virtue of tiny nano-machines constantly trying to repair our parts- again according to instructions, literally digitally coded plans in this case

Without a pre-determined plan to follow, unguided nature applies entropy by default, in every instance we see,

sorry bout that!

A sand dunes, being much larger than a castle in size and dimension, has coherent ordering across distances much larger than a sand castle, making it more ordered. You have the illusion of it having less order as you can see only a fraction of it. Just as the order of your sandcastle may elude an ant.

 

[siti]

...a well ordered crystal would allow its molecules greater degree of internal freedom than a cramped crystal, making the orderly crystal have more entropy.

I don't get this! I don't get what you are saying. What is a "cramped crystal"? The more ordered a crystal structure is, the higher its entropy and the less 'internal freedom' the constituent molecules have. That - as far as I can see - is what a crystal is - a well-ordered, high entropy arrangement.Or am I missing something?

...entropy has nothing to do with structure but with energy...

...and energy is what determines structure...high energy (low entropy) structures are less stable and therefore less likely to be encountered in nature - that's what makes molecules (and crystals) take the shapes they take.

BTW - I read the blog post as far as the example of the sun/earth thing. But if you are talking about the sun 'losing entropy' because energy (not to mention mass) is lost to the surroundings - including the earth - then you are not treating the sun as an isolated thermodynamic system and the 2nd Law calculations will obviously not work. Indeed, the sun is certainly not an isolated thermodynamic system anyway so I'm struggling to figure out how useful this example could be. This guy's blog page says he is an associate professor in physics but that looks like a high school science class error to me - maybe I'm missing something again??? (Or maybe not!).

 

[sayak83]

I don't get this! I don't get what you are saying. What is a "cramped crystal"? The more ordered a crystal structure is, the higher its entropy and the less 'internal freedom' the constituent molecules have. That - as far as I can see - is what a crystal is - a well-ordered, high entropy arrangement.Or am I missing something?

...and energy is what determines structure...high energy (low entropy) structures are less stable and therefore less likely to be encountered in nature - that's what makes molecules (and crystals) take the shapes they take.

BTW - I read the blog post as far as the example of the sun/earth thing. But if you are talking about the sun 'losing entropy' because energy (not to mention mass) is lost to the surroundings - including the earth - then you are not treating the sun as an isolated thermodynamic system and the 2nd Law calculations will obviously not work. Indeed, the sun is certainly not an isolated thermodynamic system anyway so I'm struggling to figure out how useful this example could be. This guy's blog page says he is an associate professor in physics but that looks like a high school science class error to me - maybe I'm missing something again??? (Or maybe not!).

There is no error at all in the blog post. The idea is simple. Increased number of micro_states do not automatically imply increased disorder. The sun example is there to correct the common mistake that somehow all the heat and light being radiated by the sun causes an increase in its entropy value. It does not.

I would refer you to an excellent paper called "insight into entropy" by Daniel Styer to get a feel for the types of cases where a system's entropy increases along with order. A discussion of some types of crystal phases is also provided. It should be available as a pdf.

 

[siti]

The sun example is there to correct the common mistake that somehow all the heat and light being radiated by the sun causes an increase in its entropy value. It does not.

But if the sun is (as indeed it is) radiating heat and light then it is not (as indeed it is not) an isolated thermodynamic system and the evaluation and evolution of its "entropy" is not described by the second law of thermodynamics. Attempting to plug energy and temperature values from a dynamic system with enormous interactions with its environment into the equations will just yield meaningless numbers. It makes little sense (as far as I can see) even to talk about the "entropy" of the sun in the current phase of its "life" cycle (perhaps when it has finished radiating all its energy in - who knows - maybe 30 or 40 billion years, then it will be a "dead" star, with no nuclear reactions going on, cold, dark and stable and - essentially - isolated from the rest of the universe by even colder, even darker empty space - then it might make more sense to talk about its entropy. For now though, I reckon one might just as well attempt to calculate the entropy of a human being before and after dinner.

I will look up the reference you have indicated though. It is, after all, more than 30 years since I studied entropy and thermodynamics, so if Claude Shannon was right (?!!) to borrow the notion of entropy to describe information systems, I probably need to reorder that data in my information system by now!

 

[sayak83]

But if the sun is (as indeed it is) radiating heat and light then it is not (as indeed it is not) an isolated thermodynamic system and the evaluation and evolution of its "entropy" is not described by the second law of thermodynamics. Attempting to plug energy and temperature values from a dynamic system with enormous interactions with its environment into the equations will just yield meaningless numbers. It makes little sense (as far as I can see) even to talk about the "entropy" of the sun in the current phase of its "life" cycle (perhaps when it has finished radiating all its energy in - who knows - maybe 30 or 40 billion years, then it will be a "dead" star, with no nuclear reactions going on, cold, dark and stable and - essentially - isolated from the rest of the universe by even colder, even darker empty space - then it might make more sense to talk about its entropy. For now though, I reckon one might just as well attempt to calculate the entropy of a human being before and after dinner.

I will look up the reference you have indicated though. It is, after all, more than 30 years since I studied entropy and thermodynamics, so if Claude Shannon was right (?!!) to borrow the notion of entropy to describe information systems, I probably need to reorder that data in my information system by now!

One can easily calculate the entropy of the sun. One simply needs to know it's temperature and gas composition and use the macroscopic laws by Clausius.
It's also entirely possible to calculate the entropy of human beings before and after dinner. Since he is mostly water in a constant temp bath, you just add the entropy of water in the food at human body temp and the result will not be far off. Calculating entropy of systems is quite easy.

 

[viole]

It's one of the most perversely propagated scientific misunderstandings in the world. The concept of entropy has nothing to do with order or disorder whatsoever. It has to do with how many microscopic quantum states are accessible to the particles in the system at a given energy. There are many ways to put this but let's think of it in terms of economics.

Consider two nations with the same GDP(energy) but in one case we have a
1) Highly unequal society with centrally managed economy(North korea) . There all the money is concentrated in the hands of a few and, more ever one can only use the money to buy one and only type of state made product (one type of state made car, state made house, state made popcorn etc.). In such a society the distribution of money is very concentrated... it's in the hands of a few and distributed among the state approved products. If this were a nation of molecules, we would say that their energy can be distributed in a narrow set of options and hence it has low entropy.

2) Highly egalitarian and capitalistic nation(Sweden). The money is roughly equally distributed and an individual can invest it in lots and lots of possible products. If this were a gas, we would say energy is well distributed and each molecule can partition its energy into many modes. Such a system (which can be much richer and complex and vibrant than 1) will have a higher entropy.

So the 2nd law states that an isolated thermodynamic system in the universe evolves towards greater liberty and equality. Yay!

Notice that this has nothing to do with disorder and is completely inapplicable for determining order and disorder. Thus

1) A pack of shuffled cards have the Same entropy as a pack arranged in accordance to color suites
2) A bound book has the same entropy as a random arrangement of its torn up pages
3) An Egyptians mummy has lower entropy than a living human (has to do with water content)
4) Sun is losing entropy by radiation.
5) The concept of entropy applies to elementary particles and their quantum states only, does not apply to anything else (shuffled cards, messy rooms or North korea).
Etc.
The universe had lower entropy earlier simply because it was so dense and hence its matter and radiation were too crammed in to be "free". Think Japan, people have to live in tiny flats and can't spread out as there's no room.

More detailed explanation (with some math) in the link below

Elusive Entropy | Do the Math

Bottom line :- there should be a moratorium on scientists trying to connect everyday words with scientific terms.

Here's the same message from the royal society
What is entropy?

I agree, in principle. Bottom down, it all depends on the definition of disorder.

Entropy is information. Ergo, information is physical. Basically, it is the minimal amount of bits that can completely specify the state of a system. Maximal entropy is the maximum amounts of bits that can specify the state of the system.

In other words: maximum entropy is the storage size (in bits) that can be used to specify any state of the system. The current entropy is the number of bits of that storage actually used.

Therefore, it is entirely possible that a system with a small storage and in equilibrium (maximum storage used), uses less bits then another system, very far from equilibrium, with a much higher storage capacity. The latter (more bits, and therefore entropy, even if far from equilibrium) would then be more "disordered" then the "former", which seems absurd.

Another mistake popular science does is to declare that entropy can only increase or remain constant. This is simply not true. There is no law of physics that prohibits a system to spontaneously get less entropy. It is just very unlikely if the system is far from equilibrium. But when it is in equilibrium, for instance, entropy could very easily decrease (even if not that much, probably).

And if we wait long enough, any initial configuration will be repeated. Poincare theorem shows why that must happen.

Now, science says that while entropy increases, information remains constant. The solution of this apparent paradox is left as a simple exercise to the reader.

Ciao

- viole

 

[Revoltingest]

I agree, in principle. Bottom down, it all depends on the definition of disorder.

"Disorder" is an awful term because it has common lay usage which differs
from the tortured technical definition used for statistical mechanics.

Entropy is information.

No. Entropy is an emergent thermodynamic property of statistical mechanics.
Might as well say "temperature is information", or "combustion is information",
or "everything is information". Where does that get us?

Note: There is an unrelated appropriation of the term....
Shannon entropy - Wiktionary

Another mistake popular science does is to declare that entropy can only increase or remain constant. This is simply not true. There is no law of physics that prohibits a system to spontaneously get less entropy.

There is the 2nd Law Of Thermodynamics.
On any level above quantum mechanics involving a single particle, this law is inviolate.

It is just very unlikely if the system is far from equilibrium. But when it is in equilibrium, for instance, entropy could very easily decrease (even if not that much, probably).

And if we wait long enough, any initial configuration will be repeated. Poincare theorem shows why that must happen.

Now, science says that while entropy increases, information remains constant. The solution of this apparent paradox is left as a simple exercise to the reader.

Ciao

- viole

Shannon Entropy should not be conflated with thermodynamic entropy.
Try designing a heat engine which violates the 2nd Law Of Thermodynamics.
It won't work....unless use the Infinite Improbability Drive. (Not on the market yet.)

 

[Revoltingest]

More on the terms, "order" & "disorder".....
Ref....
Entropy (order and disorder) - Wikipedia

In recent years, in chemistry textbooks there has been a shift away from using the terms "order" and "disorder" to that of the concept of energy dispersion to describe entropy, among other theories. In the 2002 encyclopedia Encarta, for example, entropy is defined as a thermodynamic property which serves as a measure of how close a system is to equilibrium, as well as a measure of the disorder in the system. [2] In the context of entropy, "perfect internal disorder" is synonymous with "equilibrium", but since that definition is so far different from the usual definition implied in normal speech, the use of the term in science has caused a great deal of confusion and misunderstanding.

We can blame Helmholz....

This "molecular ordering" entropy perspective traces its origins to molecular movement interpretations developed by Rudolf Clausius in the 1850s, particularly with his 1862 visual conception of molecular disgregation. Similarly, in 1859, after reading a paper on the diffusion of molecules by Clausius, Scottish physicist James Clerk Maxwell formulated the Maxwell distribution of molecular velocities, which gave the proportion of molecules having a certain velocity in a specific range. This was the first-ever statistical law in physics.[3]

In 1864, Ludwig Boltzmann, a young student in Vienna, came across Maxwell’s paper and was so inspired by it that he spent much of his long and distinguished life developing the subject further. Later, Boltzmann, in efforts to develop a kinetic theory for the behavior of a gas, applied the laws of probability to Maxwell's and Clausius' molecular interpretation of entropy so to begin to interpret entropy in terms of order and disorder. Similarly, in 1882 Hermann von Helmholtz used the word "Unordnung" (disorder) to describe entropy.[4]

 

[viole]

"Disorder" is an awful term because it has common lay usage which differs
from the tortured technical definition used for statistical mechanics.

No. Entropy is an emergent thermodynamic property of statistical mechanics.
Might as well say "temperature is information", or "combustion is information",
or "everything is information". Where does that get us?

Note: There is an unrelated appropriation of the term....
Shannon entropy - Wiktionary

There is the 2nd Law Of Thermodynamics.
On any level above quantum mechanics involving a single particle, this law is inviolate.

Shannon Entropy should not be conflated with thermodynamic entropy.
Try designing a heat engine which violates the 2nd Law Of Thermodynamics.
It won't work....unless use the Infinite Improbability Drive. (Not on the market yet.)

I am not sure I agree. If we consider the entropy of a black hole, for instance, that seems to be reduced to the amount of bits mapped on its surface. This is also why throwing a body in a black hole will cause an increase of its horizon by the exact amount required to store the system state of that body.

And you are partially right. That machine won't work. With a very high probability, proportional to the amount of time it is supposed to work.

So, since you believe entropy cannot possibly decrease. Can you show me the fallacy in Poincare recurrence theorem? Or can you show to me what laws of physics prevent a system in equilibrium to have fluctuations away from equilibrium?

Ciao

- viole