What is the Second Law of Thermodynamics?
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- Опубликовано: 25 авг 2024
- What is entropy? Why is it always increasing? And what does that even mean? Dr Valeska Ting explains the second law of thermodynamics.
This is the day 12 of our 2016 advent calendar on thermodynamics. Watch all the films here: www.rigb.org/ch...
Valeska walks us from a simple mathematical demonstration, through coffee and refrigerators, and right up to the end of the Universe and everything in it.
The second law of thermodynamics states that entropy, which is often thought of as simple ‘disorder’, will always increase within a closed system. Ultimately, this is one of the key elements dictating an arrow of time in the Universe. And how is it possible that complex ordered organisms and structures have developed, if everything should be becoming less ordered over time? Valeska explains.
The 2016 advent calendar explores the four laws of thermodynamics with a new short film each day, with explosive demonstrations, unique animations, and even a musical number. Open the calendar at www.rigb.org/ch...
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I just wanted to say that I really enjoy this thermodynamics special series!
Read some pieces about the 2nd law but didn't quite get it. The video made the 2nd law very understandable. Excellent explanation!
The human body is Not a closed system... Brilliant!
Well, I mean, we aren’t.
Yes
Universe it self is!
True organisms are open systems as they interact with the universe ( surrounding s)👍
yeah who would have guessed that lol
another example of the second law of thermodynamics is.. my marriage
You can undo it at a cost!
@@SnakePlissken1 the title will go awat. But the damage will always be there.
@@alanodulio1920 no equilibrium indeed!
Hahahahahhahahahahaha! There is alaways at least one golden comment in each video and this is it
what is awat?????????
"Entropy always increases" is in fact a theorem deduced by Clausius in 1865:
Jos Uffink, Bluff your Way in the Second Law of Thermodynamics, p. 37: "Hence we obtain: THE ENTROPY PRINCIPLE (Clausius' version) For every nicht umkehrbar [irreversible] process in an adiabatically isolated system which begins and ends in an equilibrium state, the entropy of the final state is greater than or equal to that of the initial state. For every umkehrbar [reversible] process in an adiabatical system, the entropy of the final state is equal to that of the initial state."
Clausius' deduction was based on three postulates:
Postulate 1 (implicit): The entropy is a state function.
Postulate 2: Clausius' inequality (formula 10 on p. 33 in Uffink's paper) is correct.
Postulate 3: Any irreversible process can be closed by a reversible process to become a cycle.
All the three postulates are totally unjustified - clever scientists are well aware of that:
Uffink, p.39: "A more important objection, it seems to me, is that Clausius bases his conclusion that the entropy increases in a nicht umkehrbar [irreversible] process on the assumption that such a process can be closed by an umkehrbar [reversible] process to become a cycle. This is essential for the definition of the entropy difference between the initial and final states. But the assumption is far from obvious for a system more complex than an ideal gas, or for states far from equilibrium, or for processes other than the simple exchange of heat and work. Thus, the generalisation to all transformations occurring in Nature is somewhat rash."
Ok.
The Third postulate was a fine point...
Thanks for a great explanation and inviting presentation! I fully understand the concept now and I actually enjoyed trip!
as someone who already thoroughly understands the second law of thermodynamics, the only thing I took away from this video is that Dr. Valeska Ting doesn't respect eggs.
They edited the part where she scooped it up with a spatula, removed the shell fragments and placed it on her steaming hot gyu-don.
@@PrinceBlake,
Have a bit of respect !
Thank You RI for these series. of video I could remember the concept s easily in my exams
Thank you for explaining the second law so well. I have learned alot. Thank you!
Great video. A difficult concept made a little easier to grasp.
Thank you very much for explaining with actual experiments. It really helps in understanding these concepts. Thanks again!!!!
I just wanna say this video helped me understand The Crying of Lot 49.
nice
All systems are open. There is no such thing as a system closed to heat transfer. Insulation slows down heat transfer, but it doesn't stop it. Subsystems can be created that appear to go against the 2nd Law, but ONLY with outside creative input of additional energy to counteract said Law.
I was having the same thought
Thank you I couldn't understand this at all until this
The universe’s heat death (3:16) implies that it is a closed system, which therefore implies it is not infinite i.e. there are a finite number of galaxies, stars, atoms and energy in the universe.
If any of these things were infinite that would imply an infinite amount of energy exists in the universe which would contradict the hypothesis of the universe’s heat death.
Given most physicists accept the universe heat death hypothesis, then they *must* accept the universe is finite, yet this does not seem to be the case - please explain why this contradiction exists and which part of the argument I’ve presented is incorrect.
Is this all assuming the universe is a closed system?
I think it assumes that, which seems reasonable unless there is somewhere energy can go to "outside" the universe...which I think would imply that energy "outside" the universe could also go to universe.
If the universe is in a constant rate of expansion doesn't that imply the universe is increasing energy and wouldn't a black hole potentially be outputting energy outside our universe
Maybe, maybe not. I do not think black holes work that way. All the stuff they "eat", they gain in mass. Hawken radiation allows them to radiate energy back into the rest of the universe.
Until evidence shows us different than yes, we have to assume that. But it's not like we don't have plenty of evidence pointing towards that it is closed. Science doesn't assume the way religion assumes.
Science assumes a lot. Evolution is the assumption that a fish can spontaneously or gradually turn into a bird. Another theory is that life started in a primordial pond or humans came from apes. Another evolutionary theory is that animals including humans started as a plant. Yes, all of these theories are taught in biology classes all around the USA. Scientists want people to believe in a theory that they themselves have not agreed upon. A species turning into another species is based on assumptions. The mutation of bacteria is used as an example of evidence of speciation. No matter how many mutations occur that makes a bacteria different, it is still a bacteria. Even in your answer, you said science makes assumptions.
Would have been interesting to see a visualisation of where the "present day" universe is along the big-bang to heat death timeline (i.e how far 13.772 billion is compared to 10^26 years). Great video (and series).
it wouldnt even be 1 pixel across on your screen
Which is what would make it interesting (a visualisation doesn't have to be static - it could convey the difference in scale in an interesting way - like htwins.net/scale2/)
The way I learnt this was by the formula that days entropy is the natural log of the boltzman constant multiplied by the number of microstates. Microstate makes way more sense than "disorder".
delta s = klnW
The only thing from your phrase I understood is Boltzman, which sounds like a Jewish name. Microstate is something like Vatican?
Can I assume then that the Second Law of Thermodynamics would refute the Big Bang Theory of creation?
Yup.
awesome explaination sis
Thanks for explaining! Other video tried to do it with tea, and I couldn't understand anything, cream and ice in coffee make much more sense.
Could've been emphasized with some more focus on illustrations, but a good first start primer.
most understandable explain i have ever heard about second law of thermodynamics 👍
Thank you very much for this candid spread of information upon Entropy
I love the way she talks and her smile. I get it pretty well but I'm pretty distracted by her smile and the way she jumps a little with excitement whenever she's about to explain the next part of the concept.
one of the best explanations, thanks!!
I'am suppose to be playing this game but this on player keeps kicking my ass.
theLegend27?
This was sooo helpful!!
This made things a lot clearer! Thank you!!
really good stuff - minor point: i believe 10^26 is a 1 and 26 zeros, rather than 100 and 26 zeros
She said, "10 with 26 zeros behind it," which is 10^26. She is correct.
@Niranjan Rajesh you are correct my good sir. I see that now.
First time I understood entropy much better
My understanding was that a closed system allows energy input and an isolated system does not. So only the latter is relevant. The speaker used the terms interchangeably. Also, I don't know how helpful the word disorder is - entropy has SI units which the speaker didn't introduce or show how entropy is calculated. Of course, there are limits to the scope if a simple introduction like this.
Matter. The inside of a ten inch lead safe left in a desert is closed whereas it's not isolated to energy. Put it in a shielded vacuum chamber and it's isolated.
I don't follow, why not? I'm saying that a closed system is defined as one that blocks matter transfer but can allow energy input and escape while an isolated system also blocks also energy.
I always heard a closed system has no input or output. This is thermodynamics. In other fields it would have other meanings.
I take no hot comfort in cold predictions but thanks this easily explains why we did not evolve but we’re created sort of like refrigerators!
This video made me understand
Her haircut is an example of entropy - chaos and order in one place. That's what human is... and everything too. From this point of view.
Stick to your day job bud.
@@akumar7366 did that cause entropy in your pants too.
After watching 3 videos I finally understand what the 2nd law of thermodynamics means. Thank you
Would you explain what became evident to yo after watching this presentation?
@@lowellfast490 As I stated in the comment: what the 2nd law of thermodynamics is
@@UseTheLess00 Did you finish your reply? I see nothing after the word “IS”.
I did finish my sentence, yes.
In English you can use "I know what {something} is" to say you know the meaning of that {something}
What about water and oil?
thats becuase water is polar
thanks. you gave me the best explanation
Nice work. It would be interesting to create a model adding the input of life force to the idea of thermal equilibrium. If you could consider the prospect that life force animates matter and could motivate energy. As in a "hole in space" that influences the closed system, life force may be a contributing factor and it would be interesting to calculate if this was so, and is there a deficit in the energy in the universe compared to the energy that should exist in the Newtonian universe. This idea is not religion but looking for missing energy. You could take this back to the protouniverse that must have existed before the big bang.
Really really well done
Where does gravity get it's energy from to prevent entropy
From the mass of an object
@@theohwlf never seen or heard of that experiment
@@jaythomas3224 Cavendish experiment. It was done 3 centuries ago i believe.
This was so helpful
Entropy is the chaos we generate in this world the more entropy we create, the less energy is left over to do useful work
Concept of arrow of time: tells which direction the time is travelling in
If a process generates entropy, it will happen spontaneously and will be irreversible if u put in more energy
This law is applicable for closed system
Humans are not a closed system, are always exchanging heat with our environment. We are always decreasing entropy at the expense of entropy of environment
I thought the second law of thermodynamics is that things become more random..'entropy'
but she's just explained that if you turn your fridge off, the temperature inside will come into thermal equilibrium with the outside environment... But that wouldn't be random...
Correct me if I'm wrong but basically what the 2nd law is is that we're always giving off energy by simply existing like in the form of heat or noise buy that heat or noise energy given off by us will never transform back into us so the entropy is our energy being mixed in with the air around us
This is so hard to understand
U look beautiful
@@smajaykumar back off she's mine
How is this hard to understand?
Lots of physics is -- but only because it's unfamiliar. Don't expect laws of nature to "make sense" to our contingently evolved brains. We were formed on the African savanna -- the universe is a lot more varied than that. What's amazing is that we can make sense of things outside our birthplace's environment.
@Psalm 27:2 you put this in words so beautifully
Light photon ∆E=hf energy is continuously cascades down from the Sun forming greater degrees of freedom for statistical entropy forming the Second Law of Thermodynamics.
We have the irreversible processes of classical physics, such as heat energy always flowing from hot to cold and friction always changing motion into heat. Forming an arrow of time within each reference frame.
The spontaneous absorption and emission of light photon ∆E=hf energy is forming potential energy into the kinetic energy of electrons.
Kinetic Eₖ=½mv² energy is the energy of motion of what is actually happening.
An uncertain ∆×∆pᵪ≥h/4π probabilistic future is continuously coming into existence with the exchange of photon energy.
Great little video.
Nothing complicated than to think about what entrophy really mean ..
This was a very helpful video, thank you!
When does complexity turns in into disorder? Isn't that subjective dependent on cognition and computation power? Where one person can only see chaos another can see a complex order.
That is the problem with our understanding of the second law of thermodynamics. A sytem can be drawing energy from outside its boundary to increase complexity and that is not dependent on only temperature either, isn't that true? Complexity can carry on increasing even after temperature equlibrium.
Well Yes, but this law is not an absolute law in the same sense than the first. The entropy of a closed system can decrease in any limited time, but if you allow enough time it will increase. Also this law is not fondamental in the same sense as the other laws. You can simulate it numerically by pretending on the computer you have a closed container with a number of particles that initially have some energy each. A more accurate way of stating the law, is that in any defined time interval, the chance of the entropy increasing is greater than the entropy increasing. Also if you take it as a fundamental law, it amounts to contradicting the first law. Then you must accept that the energy in the Universe was created by the big bang in a wound up zeroentropical state, but that violates the first law.
3:45 10^26 is a 10 followed by 25 0's, or a 1 followed by 26 0's, not 10 followed by 26 0's. Otherwise, good video!
I also thought this
That was what exactly came to my mind too
Nice...i want my ice cube back when youvare done with it.....!!
Nicely explained...
Misunderstandings in Ideas about Entropy
Misunderstandings in Ideas about Entropy Many discrepancies in understanding the problems of life and evolution from the standpoint of physics and physical chemistry are typically associated with misconceptions in understanding entropy [4-7]. The term "entropy" was coined by Rudolf Clausius. Following his model of the world (universe), he stated: "The energy of the world is constant. The entropy of the world tends to the maximum". Later this statement was chosen by J.W. Gibbs as an epigraph to his paper "On the Equilibrium of Heterogeneous Substances". These scientists have given this statement in relation to their model of the universe. This model corresponds to a simple isolated system of ideal gas, i.e., an isolated system of ideal gas, in which the energy and volume are constant and only the work of expansion is performed. The entropy of such a system can only increase! It should be noted that when we speak about the ideal model that would correspond to the real universe, it would be necessary to accept the unreal assumption that any form of energy in the real universe will be transformed into thermal energy. Only in this case, and under additional unrealistic assumptions, the real universe "would turn" into the Clausius-Gibbs model of the ideal system. However, science amateurs applied representations of simple systems to systems of other types, in which interactions takes place between particles of different nature (interactions of molecules or other objects of different hierarchies) and to systems which interact with the environment. Some scientists, who are not professionals in the relevant fields of knowledge, did not escape such errors. This led to unimaginable confusion and slowed down the development of science for more than a century. There are thousands of publications in scientific journals and popular literature containing marked misunderstandings. To these were added incorrect ideas on negentropy and on dissipative structures in the living world and the false identification of "the information entropy" with the thermodynamic entropy. On General Physical Principles of Biological Evolution International Journal of Research Studies in Biosciences (IJRSB) Page | 9 The origin of life and its evolution can be easily explained from the standpoint of hierarchical near-equilibrium thermodynamics of complex dynamic systems. This thermodynamics is established on a solid foundation of equilibrium thermodynamics, thermodynamics of R. Clausius, J.W. Gibbs, and other great scientists.
I'm 11 this helped me learn. Not for school just curious
CHAOS WILL ALWAYS TRIUMPH OVER ORDER....it is the way of things
Thanks
There is a mistake. 2nd law only tells you that in a closed system, entropy cannot decrease, not that “it is always increasing”. Big difference.
Closed system or isolated system ? - big difference between the two.
@@KM-leons can you please explain me the difference between the two sir
@@mythicalmonke8895 Isolated system is a system where there is no transfer of energy or matter between the system and the surroundings.
On the other hand, closed system is a system where there is transfer of energy between the system and the surroundings but no transfer of matter.
The Second law Of Thermodynamics primarily deals with an isolated system.
@@KM-leons No, if it was an isolated system there wouldn't be any heat transfer, therefore no entropy transfer Q/T. Clausius defined entropy using the closed system idea. Then, later it was generalized to open systems. I agree with Gyftopoulos and Beretta that the laws of Thermodynamics are independent on the type of system. They hold true no matter what is the description of the system although historically 2nd Law comes from a closed system formulation.
@@JC-kb8vb I agree that there are different proposals. But most standard text books define the Second Law based on the features of an isolated system.
I do not follow why the eventual temperature equilibration of the Universe implies no drivers for spontaneous thermodynamic processes. Many reactions have negligible entropy change and so the position of their equilibrium is not affected by temperature, and many reactions have negligible activation energies so don't require significant temperature to go. The decomposition of nitrogen triiodide is still spontaneous if it starts at the same "cold" temperature as its surroundings. The driver is that the final state is more stable than the initial state (even if the decomposition didn't increase entropy).
Really, good explanation
Is isolated same as closed system ? because in other defenitions of 2nd law says "isolated" instead of closed.
Order from local Chaos very poetic
So is this why ghosts are impossible? Given the description of ghosts being “energy” for some unknown reasoning, that energy would not be able generate itself, let alone sustain itself throughout the ages due to entropy? Most people invoke the first law to describe ghosts, but then disregard the second law because “ghosts don’t have to follow the natural laws”, leading to a contradiction in logic, reasoning and the science as we know it.
Like as the waves make towards the pebbled shore, so do our minutes hasten to their end. Each changing place with that which went before, in sequent toil all forwards do contend.
hi i have a question. What do you mean by closed system?
Nice and neat. Thanks
Well done
The Final Question (Asimov) addressed the heat-death part :)
What about the Poincaré recurrence theorem? Wasn't a paper published a couple of years ago calculating the time scales for the entire universe
they should just calculate for the big bang part of the universe. the rest seems to take care of itself.
thermo is hard enough without that piano playing in the background.
I luv this thank u!!!
Excellent presentation (despite the totally unnecessary and distracting background noises for people with hearing problems, like me -- please remove the noises!). More importantly, the talk mentions eggs being broken but does not mention the HUGE increase in order during the hatching process after the egg has been laid (e.g. egg of a chicken, duck, avocet, turtle, alligator, crocodile, etc. etc.). The changes within the egg include not only construction of enormously complex physiological structures but also production of species-specific forms of spatial intelligence available immediately after hatching. How does all the chemical goo in a new-laid egg get rearranged to provide highly differentiated physiological mechanisms and also control mechanisms for complex behaviours needed after hatching? I think this problem has not been noticed by physicists, biologists, neuroscientists, philosophers ... I wonder whether the presenter has any ideas about this!
Thanks a lot
Wanna hear an awesome explanation of Entropy, there's an hour long radio documentary about Entropy on a radio show called "Ideas with Paul Kennedy" and the episode is just called "Entropy" . It's on RUclips, you'll thank me later .
i cant find it
I understood 100%
The flaw of the Second Law of Thermodynamics is how is the initial conditions of energy not in equilibrium (when the universe is a closed system), i.e. what created this "order" in the first place.
In 1:09 if atoms are boxes then what are balls called. what is meant by ordered and disordered here.
The boxes represent “space” (or degrees/amount of freedom). Atoms tend to spread out. Once/If the boxes are all filled up of evenly spread then it is in equilibrium & no more “meaningful” work can be extracted from such a (close/isolated) system.
i really enjoyed this video good stuff! But...regarding the fact that, theoretically, the universe will one day cease to allow any existence of anything because of the equilibrium of heat, however long it may be from now, is a disturbing statement.
So how does earth's atmosphere contained?
Nice speech ...
I don't think that entropy is a bad thing. Something is increasing the chaos, there should be a reason for that. Entropy can't increase by itself only.
Human has a serious misconception about energy. Energy is usually expended by using direct. However, if we use energy indirectly, it can be used without spending zero percent. This way more energy can be generated without wasting energy..
Cheers
Does entropy solve the riddle of the hen and the egg? Also does entropy apply to cascade effects like the one in closed systems as reactors?
the egg was first. evolution solves that "riddle". (other) dinosaurs/birds also lay(ed) eggs, and chicken have a (female) ancestor that cannot be recognized as a hen; it did lay eggs.
@@chezeus1672 ?
@@chezeus1672 ok but did those chicken-like animals come first or their eggs? you’re just avoiding the question, you have no real answer 😂
Actually, the riddle is "Which comes first: the Chicken or the egg?", where the word "Chicken" means the species, both hen (female) and rooster (male).
The answer: the chicken, according to the Biogenesis law.
@@emperor8716 Che "solved" the chicken-riddle with the riddle "Which came first: the dinosaur or the egg?"
I have a problem with things always turning from hot to cold… It just seems like the outside surrounding temperature would be a real indicator as why things turned hot or cold… For example if somebody put an ice cube in their mouth and ice cube is not going to turn cold because of the surrounding body temperature around it.
On the flipside of that let’s just say you had a scolding hot cup of coffee but you put it on the planet venus which is much hotter That cup of coffee is not going to get cooler it will get hotter… Can you please explain to help me understand this better?
You don't need to move coffee all the way to Venus, you can use a microwave or a regular oven to warm it up. Ice cube in mouth follows the first law of thermodynamics, as the water, which ice is made of, exchanges warmth with your body, it thaws as you get colder.
Many things wrong. Chaos or disorder is not the same entropy. The Second Law is statistical, and it permits spontaneous processes to reverse - although this is unlikely. Entropy is not changed by particle position-there has to be an energy dimension. The easiest way to view microstates is as ways in which energy can be distributed in a collection of particles.
So in the beginning the 2nd law of Thermodynamics did not exist?
Thanks. 🙂
Do you mean after 10 to the power 26 years "hypothetically" we won't be able to move our body and machines won't be able to work and UVR won't be able to trigger photosynthesis?
Thermodynamics in the universe break down through entropy but this creates more energy in collapse or explosion generating huge amounts of radiation & altered atoms of gasses that will drift through space until it reunites in another way. This is how systems die & renew, like a series of big bangs. We see dying supernova becoming black holes which will become so dense they too will collapse, atoms change under pressure but are not lost.
I still don't fully understand why it is, as you say, 'impossible' for milk and cream to spontaneously part. I mean, in practice of course, I get it, but by following your statistical analogy, even while the chance of all balls being in the same box is very, very small, there still is a probability of this occuring right? So why is it impossible for this not to happen?
maartenh94 I have the same question. I remember that many years ago, in a book about philosophy of science, I read that laws of thermodynamics are obtained by induction. Thus, theoretically there is a slight chance that in a hot summer, water in an outdoor pool suddenly freezes. Such an event would decrease entropy of the universe yet it does not challenge thermodynamics; because the thermodynamic state is as possible as any other single state of the system.
Farshad Mozaffari I am actually following a course on philosophy of science right now, and indeed this was one of the examples used against Popper's falsificationalism. Popper argued against induction in any form, and because thermodynamics do not predict any state to be impossible, following his theory you have to drop the theory altogether. I only now connect the dots to why this example was used though, thanks!
Yes, there is still a chance that the cream and coffee will split again evenly. But that chance is so incredibly small, that is statistically impossible it will happen. Almost the same probability of you being able to visit every planet in every star in the universe. Not very likely.
+marcohaze
You are correct, mixing milk and cream has nothing to do with entropy, that is statistical. Entropy is not defined by statistics, it is explained through statistics but people usually get it wrong. Balls bouncing in a box is statistical. Entropy is an emergent state variable related to the transfer of heat.
If you pay attention , there is just 1 chance to happen. Now you have 10^80 atoms that can occupy maybe 10 ^ 200 places . Now calculate your chance : its more than 1 / 10^1000 anyway .
3:47 isn't that 10 followed by 25* zeroes?
at the expense of the surrounding environment ? What if the refrigerator ran on solar?
settling of suspension in liquid is not violating 2nd law of thermodynamics?
Great video! Though I am wondering if it really is necessary to waste an egg to make the point.
3:45 10^26 is 1 followed by 26 zeroes and not 10 followed by 26 zeroes :P
very confusing information. so sometimes i hear the second law stated with the term "isolated system" which is something that i've read can't exist (and thought experiments will tell you that aswell). so why say here's a "law" that doesn't apply to our reality? but sometimes they say a closed system. which seems easier to except but then i think, in a closed system if matter is moving in and out of it then energy is aswell! you can't have matter without energy or movement without energy (E = mc2 right?). so if that's true then there isn't such thing as a closed system. which would mean the second "law" is not a law at all, its not even something that applies to our universe. am i missing something?
Regarding the 2nd law of thermodynamics, the material universe is considered to be a closed system. That assumes there is no energetic interaction between our universe and anything that might be outside. But, the observable universe is considered an open system, that's why these examples violate this law. Basically, entropy increases because the universe is expanding while the total energy remains the same. So, less energy is available for work as it becomes more dispersed. Not as complicated as they try to make it look. Take care.
As i know that through the history of the universe complexity has always increased. Does it mean that complexity is disorder? Than i am just clueless.
how do autonomous machines keep their entropy low though?