puppypower Posted October 13, 2015 Posted October 13, 2015 (edited) Another adjustment please. A closed system does not allow mass (matter) to cross its boundaries. Energy, however, may do so. An isolated system bars both mass and energy. In that case you need to use G=H-TS when addressing entropy changes since internal energy can lower or increase. Edited October 13, 2015 by puppypower
swansont Posted October 13, 2015 Posted October 13, 2015 The fundamental principle of life and entropy is evident in the simple system of water and oil. If we start with water and oil, this will form two layers. If we add energy via agitation, we can increase the entropy of the system to form an emulsion. If we let the emulsion stand, without agitation, the entropy will spontaneously decrease back to two layers. This does not violate the second law of entropy because entropy is part of a larger equation connected to free energy G= H-TS, where H is enthalpy (internal energy), T is temperature K, and S is entropy. In this example, the emulsion lowers entropy because this is a way to lower the more dominate H connected to surface tension so G is minimized. There is a tendency, in discussions of entropy, to disconnect entropy from free energy and internal energy, which leads to misunderstanding. Under the special case where H=0, than G= -TS. This would make entropy free standing but this is only a special case. Closed systems do not have any change in internal energy H so this can create the more simplified special case. The interaction of water and organics, due to not always mixing, can amply the H or internal energy of living systems; membrane and water.This is maximized between water and organics and is one reason why water is so important to life. Using that source of H, entropy can be lowered into self ordering systems. For example, when protein fold, this is due to hydrophobic interactions on the protein. The protein folding is less to due to the protein wanting to bind to itself, as it is due to the need to bind to itself, because of the internal energy created by the presence of water; hydrophobic. This H is strong enough to lower the protein S into unique folds with probability equal to 1.0. Protein folding is not even subject to chance, but are extremely reliable due to H (water-organic) dominating S. When we make a cup in the factory will add H to mold it into a low S. The issue here is that michel12345 seems to be implying that the entropy would be different if a human agitated the oil/water mixture, as opposed to it happening because of some natural process. That's what I was asking about. Also, there's my question about the (change in) enthalpy of a cup.
michel123456 Posted October 13, 2015 Author Posted October 13, 2015 The issue here is that michel12345 seems to be implying that the entropy would be different if a human agitated the oil/water mixture, as opposed to it happening because of some natural process. That's what I was asking about. Also, there's my question about the (change in) enthalpy of a cup. I am saying that if a natural process agitated the mixture, that is fine and I suppose you can extract from it some safe physical meaning. But not with a cup. Because a cup will NEVER come out from any pure physical process, but the oil/water mixture will. And as much as I can understand you cannot use the oil/water mixture in the Stephen Hawking example.
swansont Posted October 13, 2015 Posted October 13, 2015 I am saying that if a natural process agitated the mixture, that is fine and I suppose you can extract from it some safe physical meaning. But not with a cup. Because a cup will NEVER come out from any pure physical process, but the oil/water mixture will. And as much as I can understand you cannot use the oil/water mixture in the Stephen Hawking example. But you still haven't explained what is special about humans being involved that changes the physics. All you've done is assert that there's a difference. Does a cup being dropped not follow the same laws of motion as a rock being dropped?
MigL Posted October 13, 2015 Posted October 13, 2015 It doesn't matter, Michael123456, if its a cup falling off a table ( both made by 'human' processes and intelligence ), or if its a rock falling off a cliff ( both natural processes ), the end result and energy changes are the same ( but differing in magnitude obviously ). Thermodynamic processes don't care about 'human' involvement, and I can't understand why you do.
michel123456 Posted October 13, 2015 Author Posted October 13, 2015 (edited) But you still haven't explained what is special about humans being involved that changes the physics.All you've done is assert that there's a difference. The special things about humans is that they build things that nature does not build by itself. Like machines, rockets, cups. It is also related to the so-called Schrodinger's paradox. Schrödinger's paradox, the paradox that living systems increase their organization despite the Second Law of Thermodynamics -------------------------------- Does a cup being dropped not follow the same laws of motion as a rock being dropped? The cup follow the same laws of motion as a rock being dropped. What I say (for the 3rd time) is that you cannot say "woaw I never see the pieces of the cup jump back and make a cup" because even normally, nature by itself cannot make a cup of tea (except with the help of humans). It is much like trying to understand physics with dad pushing constantly a child on a swing. You cannot expect to get safe results. What you do when studying physics is to eliminate the human factor and build a pendulum. AND if you use a rock instead of a cup, again you cannot sat "woaw I never see the pieces of the rock jump back and make a rock again". Because if you wait long enough, the pieces may come together. Not jumping back of course, because gravity is what it is, as I said earlier. Edited October 13, 2015 by michel123456
MigL Posted October 13, 2015 Posted October 13, 2015 No, the pieces of the rock will not come together again, no matter how long you wait. They will only come together again if useable energy is introduced into the system ( by earthquake, wind, water flows or any other natural process ). And that is exactly what humans do, when they build something ( like a cup ). So again, what's the difference ?
studiot Posted October 13, 2015 Posted October 13, 2015 A discussion about the relationship between life and thermodynamics can be quite interesting unless only one side in that discussion is allowed to speak.
puppypower Posted October 13, 2015 Posted October 13, 2015 A discussion about the relationship between life and thermodynamics can be quite interesting unless only one side in that discussion is allowed to speak. An important aspect of life that allows life to regulate entropy is hydrogen bonding. Hydrogen bonding forms between hydrogen and highly electronegative atoms like oxygen and nitrogen. What makes a hydrogen bond unique is it can be polar (a) or covalent (b). It can switch back and forth between these two states while maintaining the hydrogen bond. This is shown below with a slight activation energy hill between states. This allows the hydrogen bond to act like a binary switch between two stable states. The polar (a) state has a smaller bond length. It also has a higher enthalpy and higher entropy than the covalent state. The covalent state (b) has a longer bond length, lower enthalpy and lower entropy. The reason for the difference is the polar state lowers charge potential by lowering distance but it is not too fussy in terms of position. This allows more entropy. While the covalent state needs to expand the bond length, to allow covalent bonding orbitals to overlap. These orbitals need to be in very specific positions to get proper overlap. This exact positioning lowers the entropy and the enthalpy. By flipping the binary switch, between states the cell can adjust entropy, enthalpy and volume at the nanoscale. The observation that DNA, RNA and protein all use hydrogen bonding is because of the water-oil affect. Since this cause potential to increase, the organics evolved a way to lower this potential with water; dominant phase. This theoretically allows the binary switch and the control of entropy, enthalpy and volume to extend to the organics.
swansont Posted October 13, 2015 Posted October 13, 2015 The special things about humans is that they build things that nature does not build by itself. Like machines, rockets, cups. It is also related to the so-called Schrodinger's paradox. The paradox is about the entropy of living systems, not about the entropy of the things they create. And it certainly doesn't address the issue under discussion. The cup follow the same laws of motion as a rock being dropped. What I say (for the 3rd time) is that you cannot say "woaw I never see the pieces of the cup jump back and make a cup" because even normally, nature by itself cannot make a cup of tea (except with the help of humans). You have yet to explain why this matters. You keep repeating it, as if repetition not only makes it true but also explains why it's true. Is your objection any living thing, or is it only human interaction? Can we talk about an egg dropping instead? It is much like trying to understand physics with dad pushing constantly a child on a swing. You cannot expect to get safe results. What you do when studying physics is to eliminate the human factor and build a pendulum. You are absolutely wrong to say that you can't analyze that with physics. How hard the pushes are, what the drive and resonant frequencies are, the masses and dimensions of the swing matter. The status of the mass and driving force (whether from a living being or not) has NO EFFECT on the resulting motion. What does safety have to do with it? AND if you use a rock instead of a cup, again you cannot sat "woaw I never see the pieces of the rock jump back and make a rock again". Because if you wait long enough, the pieces may come together. Not jumping back of course, because gravity is what it is, as I said earlier. "Waiting long enough" is outside the scope of the problem. Your argument seems to be that if we change the conditions of the example then some results don't apply. Well, that should be expected when you change the conditions of the example. You have a different example. But talking about different conditions is a fallacious tactic.
studiot Posted October 13, 2015 Posted October 13, 2015 (edited) If the hydrogen bond were covalent, which hydrogen orbitals would the electrons occupy? Is your diagram referring to something specialised like this? http://jolisfukyu.tokai-sc.jaea.go.jp/fukyu/mirai-en/2011/4_11.html And how is this all related to the topic? Edited October 13, 2015 by studiot
michel123456 Posted October 14, 2015 Author Posted October 14, 2015 (edited) I really don't know what to say... You have an object that physics cannot create "just like that". In no way. Forward in time, with all the energy you want, it cannot. So when the object breaks, why being astonished that physics cannot re-build it ? As an analogy: Ask a mountain to build a car. Can it? No. Then take a car, crash it, and ask the mountain to re-build it. Can it? again, No. The mountain is physics in the above analogy. So IOW when a cup of tea breaks, you shoudn't be surprised that nature cannot re-build the cup. What one has to do is take something that nature can build by itself (salt in water, an iceberg,etc) and ask exactly the same question. The cup of tea should be discarded as an analogy. The egg too. I hope that was clear. No if you ask again why that matters, it means our minds are very far away from each other. Edited October 14, 2015 by michel123456
studiot Posted October 14, 2015 Posted October 14, 2015 Michel123456 I hope that was clear. What is not clear is why you don't respond to my comments ?
swansont Posted October 14, 2015 Posted October 14, 2015 I really don't know what to say... You have an object that physics cannot create "just like that". In no way. Forward in time, with all the energy you want, it cannot. So when the object breaks, why being astonished that physics cannot re-build it ? What part of physics is violated? As an analogy: Ask a mountain to build a car. Can it? No. Then take a car, crash it, and ask the mountain to re-build it. Can it? again, No. The mountain is physics in the above analogy. Pretty crappy analogy, IMO. This completely misses the point. So IOW when a cup of tea breaks, you shoudn't be surprised that nature cannot re-build the cup. I'm not surprised. But apparently for a very different reason than you are. What one has to do is take something that nature can build by itself (salt in water, an iceberg,etc) and ask exactly the same question. The cup of tea should be discarded as an analogy. The egg too. I hope that was clear. Why the egg? There was no human involvement. Nature built it by itself. But OK, a block of ice falls off of an iceberg, onto a hard surface and shatters. Will the reverse of that process happen spontaneously? i.e. the pieces fly together and form a block? No if you ask again why that matters, it means our minds are very far away from each other. Obviously.
michel123456 Posted October 16, 2015 Author Posted October 16, 2015 What part of physics is violated? Pretty crappy analogy, IMO. This completely misses the point. I'm not surprised. But apparently for a very different reason than you are. Why the egg? There was no human involvement. Nature built it by itself. Because it took more or less 4 billion years for nature to "built it by itself". Nature had to build life first. But OK, a block of ice falls off of an iceberg, onto a hard surface and shatters. Will the reverse of that process happen spontaneously? i.e. the pieces fly together and form a block?It depends what you call "spontaneously". How do you think the iceberg formed in the first place? For example, the pieces melted, then travelled in the arctic ocean, mixed with the Gulf Stream , evaporated, formed a cloud that snowed somewhere close to north pole and formed an iceberg. It takes time, but much less than the time nature takes to make an egg from scratch.
swansont Posted October 16, 2015 Posted October 16, 2015 Because it took more or less 4 billion years for nature to "built it by itself". Nature had to build life first. It depends what you call "spontaneously". How do you think the iceberg formed in the first place? For example, the pieces melted, then travelled in the arctic ocean, mixed with the Gulf Stream , evaporated, formed a cloud that snowed somewhere close to north pole and formed an iceberg. It takes time, but much less than the time nature takes to make an egg from scratch. The same as is typically meant by spontaneously in physics — without any influence from outside the system.
MigL Posted October 16, 2015 Posted October 16, 2015 None of the processes you mention, Michel123456, are 'spontaneous'. Melting, travelling, mixing, evaporating, forming, falling and freezing, are all processes which require energy to be added to the system. Using the 'equivalent' energy and half of the processes you mention, a cup can be easily 're-built'. So again what's the difference ?
michel123456 Posted October 17, 2015 Author Posted October 17, 2015 (edited) None of the processes you mention, Michel123456, are 'spontaneous'. Melting, travelling, mixing, evaporating, forming, falling and freezing, are all processes which require energy to be added to the system. Using the 'equivalent' energy and half of the processes you mention, a cup can be easily 're-built'. So again what's the difference ? The process I mention is cyclic. At what time can one say that it has less state than another? Swansont wrote in the original thread There are more states available for the pieces to be in when it's broken. When it's whole, there is only one state. S = kBln(N) https://en.wikipedia.org/wiki/Entropy_(statistical_thermodynamics)#Boltzmann.27s_principle What when the snow freezes and makes the iceberg again? Edited October 17, 2015 by michel123456
swansont Posted October 17, 2015 Posted October 17, 2015 The process I mention is cyclic. A cyclic process of a system that is not isolated from outside energy input. And the example of a cup breaking was not of a cyclic process, and had no external energy input. That brings me to the question which I have been asking in various forms: So what? What is the relevance that you see (what aspect of physics), because nobody else sees it?
michel123456 Posted October 17, 2015 Author Posted October 17, 2015 (edited) A cyclic process of a system that is not isolated from outside energy input. And the example of a cup breaking was not of a cyclic process, and had no external energy input. That brings me to the question which I have been asking in various forms: So what? What is the relevance that you see (what aspect of physics), because nobody else sees it? Yes, the example of the cup is not of a cyclic process. Because somewhere in the process the human mind used energy in a way mother nature usually doesn't. It had no external energy input? Maybe because you are ignoring the energy required to build the cup. You are declaring this is not of our business, we can make the experiment without taking that into consideration. A cup of tea, so what. So what? I was simply asking for an example of the same kind with an object mother nature can build. Like the one you have given, with the broken iceberg. And I am asking you, what is the "one state" corresponding to the cup of tea?. Is it the iceberg, the ice cristal, the drop of water, the snow flake, or the iceberg again? And if the "one state" = the iceberg by definition, then is there somewhere negative entropy when the iceberg is formed again? (a question I cannot ask with the cup of tea) None of the processes you mention, Michel123456, are 'spontaneous'. Melting, travelling, mixing, evaporating, forming, falling and freezing, are all processes which require energy to be added to the system. Using the 'equivalent' energy and half of the processes you mention, a cup can be easily 're-built'. So again what's the difference ? Yes, with glue, and human intervention. Again, human mind is required to build the cup. Not only energy. Not "pure physics". -------------- (edit) And if you accept glue, then you must also accept the cup jumping back onto the table, with human help of course. Edited October 17, 2015 by michel123456
swansont Posted October 17, 2015 Posted October 17, 2015 Yes, the example of the cup is not of a cyclic process. Because somewhere in the process the human mind used energy in a way mother nature usually doesn't. It had no external energy input? Maybe because you are ignoring the energy required to build the cup. You are declaring this is not of our business, we can make the experiment without taking that into consideration. A cup of tea, so what. So what? I was simply asking for an example of the same kind with an object mother nature can build. Like the one you have given, with the broken iceberg. And I am asking you, what is the "one state" corresponding to the cup of tea?. Is it the iceberg, the ice cristal, the drop of water, the snow flake, or the iceberg again? And if the "one state" = the iceberg by definition, then is there somewhere negative entropy when the iceberg is formed again? (a question I cannot ask with the cup of tea) But you have changed the conditions of the example by looking at a cyclical process. Does a block of ice spontaneously reassemble if it breaks? No, it doesn't. It takes the energy input present in that cyclical process to do so. That event is the boundary of the example — any other condition changes the situation and makes comparison invalid. There is no difference in the physics whether it's a cup or a block of ice, despite your objection. Energy leaves the system when ice forms, so its entropy can decrease. That can't happen in an isolated system. A pool of water that is isolated will not freeze. Why can't you ask the question of entropy when fabricating a cup? I don't understand why you thing that question can't be asked, if it were relevant. The "one state" is the state of being a single piece of whatever the material is — ceramic, probably. That it's a cup is irrelevant. It's only used because it's a recognizable item in its initial state.
Sensei Posted October 17, 2015 Posted October 17, 2015 (edited) What when the snow freezes and makes the iceberg again? Michel, iceberg, or snow, is not made of the same particles. It might looks similar for human imperfect eye, but it's not in the same configuration.. If you would be able to assign identifiers to each particle of water (or any other), you could trace where they're going and where are in the cyclic process the "next time".. And every snowflake is unique. In the case of cup, there is only one configuration of broken parts, where they fit, and were they where prior breaking. Edited October 17, 2015 by Sensei
studiot Posted October 17, 2015 Posted October 17, 2015 You keep claiming there are no 'natural' (ie totally independent of humans) processes that can lead to the formation of a (ceramic) cup. I proved this totally wrong in my post#22 where I demonstrated one such sequence.
michel123456 Posted October 17, 2015 Author Posted October 17, 2015 You keep claiming there are no 'natural' (ie totally independent of humans) processes that can lead to the formation of a (ceramic) cup. I proved this totally wrong in my post#22 where I demonstrated one such sequence. Sorry studiot I didn't put much importance in your post because acorn cups are also a by-product of life. But you have changed the conditions of the example by looking at a cyclical process. Does a block of ice spontaneously reassemble if it breaks? No, it doesn't. It takes the energy input present in that cyclical process to do so. That event is the boundary of the example — any other condition changes the situation and makes comparison invalid. There is no difference in the physics whether it's a cup or a block of ice, despite your objection. Energy leaves the system when ice forms, so its entropy can decrease. That can't happen in an isolated system. A pool of water that is isolated will not freeze. Why can't you ask the question of entropy when fabricating a cup? I don't understand why you thing that question can't be asked, if it were relevant. The "one state" is the state of being a single piece of whatever the material is — ceramic, probably. That it's a cup is irrelevant. It's only used because it's a recognizable item in its initial state. So let me resume your conditions: You are presenting an "isolated system" where a cup can break (IOW energy can flow in the form of impact and heat) but energy cannot come in (because it is isolated). Then you make the statement that, well, energy is flowing out but not coming in, and put a name on it, entropy. In reality the whole setup has put the conditions for this exact conclusion. Of course heat alone will not make a cup. When we change the cup with some other material that can indeed be rebuild without human help, then you say we were talking about a "isolated system" and you cannot input heat. You cannot input human intelligence, you cannot anything. Under these conditions, of course you cannot anything. Is that it?
studiot Posted October 17, 2015 Posted October 17, 2015 Sorry studiot I didn't put much importance in your post because acorn cups are also a by-product of life. Then you need to be more specific. Are you defining 'natural' as inanimate or non human or what?
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