I just want to say that the clarity of your exposition and the correct stress on the important conceptual parts reveal how deep is your understanding of physics. Everybody has something to learn from your videos, from high school students to professors.
Having been magnificently click-baited previously, now I'm greatly fascinated, and looking forward to more of your work. How much easier it would have been to learn this stuff, which I did, as a schoolboy/student in the late 50s/early 60s if the teachers/lecturers had also related the wonderful stories behind these discoveries. It makes a whole lot of difference. Thanks. PS Clausius never got a mention when I was 'taught' Thermodynamics. Or maybe I forgot.
@@keithammleter3824 Actually it's possible that the 'authorities' may have failed to notify me. It was fifty years ago. I don't forget - or have I forgotten that I've forgotten?
@@petersack5074 Science branches naturally from Philosophy by applying it to the study of matter. Of course we should all take care, and science tells us what it is that we should care for. It's nice to see some passion about this. EXCEPT: a) Life *_emerged_* from non-life, just as previously suns and their planetary systems emerged from the ashes of exploding stars, just as later still Consciousness emerged in living beings. The Universe started simple, and emergent processes began of increasing subtlety and complexity. There is no reason to suppose that the Universe has stopped EMERGENCE, and there is at present, and probably there never will be, a way of predicting the manner of the next emergence - but maybe you're looking at its very beginning. God is a myth, of course, and b) _"forces which mankind cannot even begin to understand"_ - you haven't been listening. Go study.
I think the quote "to cast the theory overboard" at @1:49 is in Clausius' 1851 paper "On the Moving Force of Heat, and the Laws..." I love your videos thank you. I will be signing up on Patreon!
I mention a bit about him in my video about the first law of thermodynamics but I haven’t made a video just about him. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-a9c7u-FM-Wc.html
I have a PhD in chemical physics, decades ago, retrained as an epidemiologist, now retired. And I am cycling back to physics and having so much fun with your videos. I think more teaching of science from a historical perspective would enhance understanding and definitely enhance retention. All of us scientists stand on the shoulders of giants and those of lesser contributors, but both need to be recognized and studied as to how they came up with all this stuff. Thank you for making these wonderful videos.
I am a 36 year old research chemist, sadly I only have a Bachelor's degree. I love learning though, and I completely agree with you. Increasing the number of different contexts in which you learn something certainly makes it easier to retain. It also helps you understand the logic of it all. I was always wondering "but why did they do this, and what was the use for it?" during my college classes. The nice woman who makes these videos has really helped me get a better grasp of some of the physics I wasn't exposed to as a biochemistry major.
BSChE 1989. Going to retire and go back to Michigan Tech to get a degree in Physics. I have two years to relearn Diff Eq, Fourier this and that, Legendre's polynomials, and matrices!, etc., before I take a class. When I went to school, seems all I did was learn math equations and be certain I could pass the test. It's all these background stories that add so much to the basic lectures. ya know? Thank you Kathy.
Physics, when taught along how it came to be the way it is, becomes one of the most beautiful things in the world! Love this video, ma'am. Amazing work!💎💎
On science, I side with the British, they invented science. German are the followers in science. They are leaders in music, almost as good as Italians.
When i was teaching thermodynamics I explained entropy as a measure of the quality of heat and gave an example of pouring a cup of hot water into a tub of cold water. The heat had not gone anywhere, but its value or quality had been reduced as its entropy increased.
If you changed that to the 'quantity' of heat rather than the 'quality' of heat I could agree with you. By summing infinitesimal quantities of heat, (integral dq), Clausius regarded entropy as a summation of heat quantities.
Brilliant video! I'm a PhD student in Chemical engineering and I think you are the very first person on RU-vid or any University I've even being (already 3), or even any book I've ever read who finally does a video with the correct interpretation of Clausius ideas. I absolutely agree with you, this ideas cannot be fully understood without the historical background of the different scientist who participated on this revolution. I wish with all my heart you could make a video explaining the second and first law combined. Where they finally concluded entropy is the conjugated variable of the temperature. I think every book has the mathematical derivation starting with dS= dQrev/T, dU = dQ + dW and dW=PdV to finally arrive with dU = T dS + PdV. However I think there is a lack of the fundamental understanding. I think somehow Clausius was thinking in the idea of disgregation and how by knowing the disgregation we could then know the temperature and vice versa. As you mentioned this idea of disgregation is connected with the position of the particles (the possible positions) which is also connected with the Boltzmann equation. I think this is all beautifully connected and I hope you can make a video talking about it =D Thanks for your video. Great Job!!! Looking forward to see more of your content!
Edwin Rg so glad you liked it and thank you for the wonderful compliment. I usually try to limit the math in my videos as I want it to be accessible to all. See what you think of my next one on Boltzmann’s entropy equation and see if it connects things in a way you like
Edwin Rg hi Edwin, I am a chemical engineering student ( undergrad ) and would like to hear from you tips/recommendation to get to know thermodynamics for chemEng. Can an undergrad chemEng student get to understand these laws by going back in history to have a knowledge on how they came? Any other tips regarding chemical engineering skills & or knowledges need to be very familiar with in the undergrad level will be much appreciated. Thank you in advance!
Edwin Rg, reduction of the Carnot Cyclic Engine in the limit to infinitesimal size produces the context of analyses of Clausius, and hence the equation dS
Edwin Rg, you would to keep in mind that Clausius did his work before the onset of the atomic age. The reduction of the Carnot Engine in the limit to infinitesimal size has a bound of the Continuum to support differentiability and is Newtonian. Here is the imputation of the modern science that follows: The entropy of a matter increases as the internal energy content of matter increases. So the abstraction: dE
Entropy is without doubt one of the most amazing facets of Physics, and your explanation of the history of its discovery is fascinating and very well researched.
There are tens of thousands of science and physics channels on this platform. However, none so concise, so informative and so enjoyably understandable as Professor Kathy's. This level of intellectual clarity in all things 'physics' is a rare treasure.
A miracle. Something on the internet that CLEARLY explains the second law of thermodynamics (and gives a history lesson). Find a way to stick some Jake Chudnow music in the background and you got something I could watch for eternity.
A. Saith, "Music " ? Heavens NO ! Do people go to a rock concert to learn science ? Hell No ! Adding noise to learning is as sensible as taking a shower while eating spaghetti. No, no, NO ! ...
Excellent. As an engineer, through college, I was taught thermodynamics in the language of Kelvin and Clausius (it was long time ago, but not nearly in the 19th Century). I never fully grasped it until in grad school I picked up a book someone left in the lab. It was titled Something-Something Statistical Mechanics and it was a revelation!
The funny thing is that the second law can be stated in twenty ways. I remember my tutor at University use to say that you can teach about Thermodynamics without mentioning entropy at all but it would be harder.
Another really good post. I think a historical perspective is valuable because to understand the answer you first have to understand the question. Indeed a correctly framed question is the necessary prelude to getting an answer to it. History gives us some, at least, of this element; plus of course the human interest. Other physics channels use this to some extent (Yong Zhong, Alexander Unzicker, Pierre Robitaile, all well worth checking out) but you Kathy are a master of this technique.
Every physical chemistry student learns the three laws of thermodynamics in the first week: of class 1: You can't win. 2: You can't break even. 3. You can't get out of the game. Thank you for a truly delightful tour of some of the most interesting and important aspects of the discovery and articulation of some of our most basic physical laws. Many years ago I was taught the Carnot cycle and phenomenological differential equations of entropy as an undergraduate. It wasn't until graduate school that I was introduced to statistical mechanics, canonical ensembles, and partition functions. It was all a very satisfying theoretical unification of macroscopic and microscopic behavior of molecules, but the macroscopic equations were much more useful in the laboratory, especially delta S = integral of heat capacity/T x dT. We used a scanning calorimeter to measure heat capacity as a function of temperature during a solid-solid phase transition in certain polymer crystals, and were able to determine the entropy change between the two solid states, which we could also predict from molecular energy models.
Entropy can also be defined as achieving equilibrium which make much more sense than disorder ( which causes confusion with man made description of disorder)
For eg : you may think that entropy of the very hot object might be high but it is not so. It depends on the environment in which it is in. Since it is very hot relative to environment the system(object ) loses its heat until it is equilibrium to the surroundings temperature. And the hot object relative to surrounding have low entropy. Entropy is first appeared and came into existence with the 'concept of spontaneous process'
I suspect Clausius used S to represent Entropy as the first letter of Sum or Sigma. Because E was already taken for Energy. He proposed using an integral as you showed, and the integral symbol is also an S, in the font style of the eighteenth century.
I had completely forgotten when I understood this very important fact. Thanks for the tune up! As it turns out, in what I am attempting to accomplish right now, this becomes very important to me! Ain't energy science a blast??
I love your term 'messyness' for entropy. Never in a million years would I have made that connection. However, I did teach my daughters that most games we played were high entropy to low entropy games. My PHd microbiology daughter knows now what that means. I've listen to many of your talks. Outstanding!
I always found it difficult to square in my head. Maximum entropy for a gas for eg. is in its lowest energy state where it is "equally" distributed. But to me that is a very "clean" arrangement not a "messy" or "disordered" one. The same goes for the universe. As everything spreads apart to my mind it becomes more uniform, or ordered in some sense. I know this just an artefact of my thinking, but I thought I'd share.
@@Celtic_Thylacine You are right, from my understanding it is not a increase in something being, "messy", or an increase in disorder, but I thought entropy was just an increase in more possible microstates of a system, an increase in possibilities! At least that is how my Thermal Physics class frames it. And I have a test tomorrow in it, which I should probably get back to studying for!
"how Boltzman got credit for an equation and a constant … _next time!"_ is the nerdiest cliffhanger ever. thankfully, I'm watching this 2 years in the future and won't have to wait.
Check out the full text 11.47mins...I'm almost as confused as I was before I watched the video...and having Greek as my second language find some of the translation for the use of Greek in mathematics lost in translation LOL...Great video...very new to your channel...think I might have the slowest bingefest of your postings ASAP 👉💎👈👉🇬🇧👈
Just discovered your channel a couple of days ago. I find your presentations both enlightening and engaging! I'm a frustrated former physics students from the mid 70's who had that pursuit close when it was discovered I have dyscalculia. So much for my dreams of being a working astronomer! However, throughout my life I've tried to keep as current as possible with both fields. I've always enjoyed rich science programs that respect the intelligence of the audience. Keep up the excellent work!
Just WOW! Thanks so much for this. Back in the Sixties I did a school Subject called "Electricity and Magnetism". I also did Chemistry, Biology and Physics. Little did I know the "Elec & Mag" subject would lead me to remark at about 24yo during my training as a Telephone Exchange Technician "Doesn't everybody know this?" All the scientists mentioned here are "household names" to me, but this background to the discovery processes is just awesome and so enlightening. I wonder how come we never learned all this. Could it be that if we had video presentations like this at the time we could have learned so much more in the time of just one class period?
So, the ability of energy to produce work is diminished over time. If time were to go on forever, the hot and cold of the universe would eventually even out and no work could be produced. How could Darwinian evolution be true. How can organization come from chaos? We should ponder these things.
Does this thinking make sense? The quantity (or amount) of energy in universe or a closed system is constant but it is always changing (or “flowing” or “transforming”) to a lower energy level. During the change (or transformation) to a lower energy level the temperature always decreases. So if you divide the change in energy by the change in temperature the result will always be increasing. So if you call the change in energy divided by the change in temperature entropy then as long as energy is always changing (or transforming) to a lower energy level entropy is always increasing. So saying that entropy is always increasing is equivalent to saying that the level of energy is always decreasing but the quantity of energy always remains the same. Edit: I thought about this some more and this is now my thinking on entropy. Does it make sense? The quantity (or amount) of energy in a closed system which could be the universe is constant but it is always changing (or “transforming”) so that it becomes less concentrated and more diluted. As the energy becomes more and more diluted there will be many states along the way that will appear to be stable or in equilibrium but these stable states are still diluting (we can also say decaying). It is just that they could be diluting at an extremely low rate that is barely detectible giving the appearance of stability or equilibrium. The more diluted the energy of the closed system becomes, the lower the temperature will be. The temperature can get close to absolute zero but never reach absolute zero. So if you divided the amount of energy in the closed system by the change in temperature for any given time period, the result will always be positive and as time increases the result will also increase. This result is what entropy is (Entropy = Energy / Temperature). So saying that entropy is always increasing is equivalent to saying that the energy in a closed system which could also be the universe is always diluting or decaying and becoming less concentrated.
لودفيغ بولتزمان هو من إخترع قانون الإنتروبي ، لكنه إنتحر بسبب الإنتروبي ، لأنه حاول أن يفهمها تماما ، فما إستطاع فانتحر *!* Ludwig Boltzmann is the one who invented the law of entropy, but he committed suicide because of entropy, because he tried to understand it completely, but he could not, so he committed suicide *!*
I recall reading Max Planck's work on Thermodynamics where all the main thermodynamic functions were expressed in entropy units the E/T and F/T. I don't think Planck's formulation is particularly insightful but still provides for tractable reasoning. The notion of absolute zero seems to come from defining temperature from the nearly linear thermal expansion of Hg in a glass tube. Boltzmann suggests that 1/T (reciprocal absolute temperature) many be more fundamental. 1/T can vary between -infinity and infinity. Can't explain negative Kelvin temperatures quickly but they can and do exist.
If the 2nd law doesn't make you depressed then you have not understood it. It is the ultimate doomer's indulgence, the emo's universe being described. It is the god of death standing behind the clock.
Nice video. Good history of science. Thanks for bringing out the brilliance and importance of Clausius. You need to adjust the lighting. It is shining too brightly on your face. Actually, entropy is much more complicated than "messiness" or "disorder" as I'm sure you know.
That was fun. As an applications engineer, it mainly reinforces my experience that new concepts are hard to explain clearly. Thompson and Clausius were pretty much talking about the same thing, but it was hard to tell. It takes a long time to agree on a standardized explanation, and like many things in the real world, politics prevents the best and clearest explanation from being used. I'm still a bit skeptical about whether entropy applies to the universe. It's great for thermal cycles, especially combustion engines. And OK, maybe there's not enough dark matter to make gravity pull the expanding universe back together and heat it up. Note that thermodynamic theories don't consider gravity or subatomic physics or relativity. My current crackpot theory is that the universe is like a great big popcorn popper with big bangs going on all the time. Perhaps a few kernels run into each other and get enough density to contract and get more gravity and boom again. I just can't accept the idea of the energy death of the universe. And I've seen lots of models break when they're applied too broadly.
"Things fall apart... it's scientific." Thought it was more nonsense lyrics until Dr. Love's entertaining lecture. The ability to make what I thought was boring subject interesting and worth while.
Hi The trouble with coming to ANY definitive formula describing physics, is the built in flaw of materialism, which fails to account for Who is holding everything together FROM THE BEGINNING, and failing to account oneself HIS created being, and therefore accountable to HIM as part of HIS creation as put forth in the Bible. Death is not accounted for in the neoclassical materialistic physics making it irrelevant as the cause of entropy of all physical states of being, until it is removed by the Creator YHWH because the reason for its present dominance over the physical world ( disobedience to HIS sovereignty)will be removed by the obedient resurrected Son upon His soon return to take up His throne. Because He is the owner and He vanquished His opponent at the cross. Materialism is total ignorance of the facts underlying existence.
oh my god... what a beautiful woman you are!! Thanks for the AMAZING video!! I loved EVERY SINGLE PART OF IT. What did you study at college/as a masters/ ph.D?? again, thanks a lot you powerful, beautiful being!!
montse fonsecaa why thanks! I studied physics in college and I got a masters in physics and in engineering science and I was all but dissertation in physics twice because I’m very bad at research and much better at studying the history. I wrote a whole thing about my background on my Patreon page and you can read it for free if you want: www.patreon.com/posts/23721265
The thing that makes entropy so difficult is that using the absurdly anthropocentric analogy of order/messiness gives people the wrong idea about what's going on, and frankly has to be unlearned before they can understand the relationships at play.
I like your videos, but disorder is a crude and misleading characterization of entropy (albeit popular), as entropy does not always lead to “disorder” (see Natalie Wolchover’s work). Entropy is foremost a reflection of the number of possible configurations a system can take (molecular positions and kinetic energy) at a particular thermodynamic state, it relates to the possibility of spontaneous change within the system.
I learned of Clausius after college when i found a large publication on thermodynamics online that devoted 100+ pages to the history of the first people to conceptualize and attempt to give mathematical construction to what they were experiencing during the 1800s.
Thanks so much! I do have a hard time wrapping my head around entropy. Could you explain what constant entropy is on a refrigerant ph chart is? My guess is it means there is no transfer of heat between inside the system and outside the system. The temperature is only increased by pressure
Hello, I enjoy your videos very much and have learnt a lot about the inventors involved in electricity and electrical devices. You are also a great teacher and have a great knack of eplaining things in an easy to understand way. I was just wondering if you have ever heard of an inventor who is largely long forgotten these days but who was one of the 20th century's greatest and most prolific inventors. His name was Harry Grindell Matthews and he invented lots of electrical items including the first mobile or cell phone (he beat Motorola by quite a few years) and also the first autopilot for aircraft, he is even alleged to have invented wireless telegraphy before Marconi but by far his most famous invention was 'The Death Ray'. Not as scary as it sounds it was a device for stopping the engines of cars and even stopping the engines of airplanes of the day. The British military was not to sure about his 'Death Ray' but it was bought by The American Military after they met him in a field in the early hours of the morning and bought it from him. One side note, After The American Military bought it off him it was supposedly used by American Military right up to the 1980's and one of the engineers that used it retired in the 1980's and became a consultant and writer on the TV Series 'Knight Rider' where in an episode he wrote a new a device for K.I.T.T. called the Micro Jammer which enabled KITT to shut down other things like Cars and Helicopters. That was science fiction but the consultant had for years used the real one invented by Harry Grindell Matthews. You can read more about Harry and his inventions in this book here: www.amazon.co.uk/Death-Ray-Secret-Grindell-Matthews/dp/0956134807?SubscriptionId=AKIAILSHYYTFIVPWUY6Q&tag=duc08-21&linkCode=xm2&camp=2025&creative=165953&creativeASIN=0956134807
Kathy produces excellent content here. I get an additional kick out of the bright lamp's reflection in her eyes. Reminds me of a wildcat talking about physics.
Please correct me if I'm wrong, but isn't one of the ideas behind entropy that if we have a 1,000,000 marbles, all identical, it doesn't matter how we arrange them because the result always looks the same. So that's a low entropy system. On the other hand, a system of 10 marbles, all different in color, for example, actually has higher entropy because each arrangement is distinct. So it's not the item of items but how many different ways those items can be arranged to produce a distinct system that is the key to entropy. I'm not too current on this idea, though. That's what I vaguely remember from a visual model of entropy I saw once. By the way, the word "karma" is Sanskrit for "action".
This is brilliant! I being an engineer could always solve these equations, but never exactly got the hang of why entropy is the way it is! Because like you, I too was taught heat can't flow from "cold to hot" without applying work. Now that you explained how Claussius thought about this, the exact other way round it all starts to make sense ! Finally, I can live in peace!
So glad this helped. I found Clausius to be very helpful to my understanding as well. Entropy is very confusing. Heck, even Maxwell had trouble with it at first.
@@Kathy_Loves_Physics oh my. It's a shocker to learn perhaps the most influential Physicist of all time had a hard time grasping what entropy was. I guess, it helps us better retrospect and appreciate the genius of Claussius
I have the same experience, having majored in electrical, I got the minimum requirements in terms of thermodynamics, and always envisioned heat flowing from a hot body to lower temp body, unless an external energy drove the process backwards as in a refrigerator. Excellent lecture.
@@Kathy_Loves_Physics i was just thinking how maxwell equations are neat and clear. BTW it's the same difference in noise and dirt from a circuit board and a thermal engine
@@amramjose That is not how refrigeration works. Liquid to gas, gas to liquid. The evaporator and condenser are on either side of a damn pump. Nothing backward about state changes and entropy.
Great explanation! 😇 Our words provide a bold affirmation of our innermost thoughts; they are a confirmation to the world of how we see others and ourselves. What you say and do is an accurate indication of what is in your heart. Words shape how individuals think, act, and learn.
Rusty-1-A.N.S. Wow! I'm just a layman about all this. However I've been very curious about Thermal Dynamics for some time now. I really wish the producers of My favorite SYFY show.."Star Trek" had actor Leonard Nimoy as "Spock" explain Thermal Dynamics, Energy, Equilibrium and Non-Equilibrium and Entropy in one of their episodes and movies "just like you have so brilliant done"!!!!!!😄 I'm a musician (Bass guitar) and felt like I was being taught almost everything about Sound, Phonons, Vibration, Infrasonic, Ultrasonic frequencies etc. Thank you Kathy 😉💯% ⚡ENERGIZE ⚡
Fabulous. Your enthusiasm shows, and your explanation is very good. Although even as an engineer who learned this stuff 40 years ago I am now going to have to replay it a couple of times!
Clearly for post-grad physicists --- I'm not one. I however would love to know what Entropy really is -- not just equations or history. This video gives background, but does nothing for me to understand the working physics of entropy, for me anyway. WHEN WILL I UNDERSTAND ENTROPY?
_τρoπή_ = _tropí_ = turn, change, etc, in modern Greek. With the prefix _en-_ from _energy,_ with ultimate roots _ἐν_ (en, “within”) + _ἔργον_ (érgon: “work.”) I think a rigorous scholar would have replaced _disgregation_ with _ergtropy_ or _tropenerg._ I, for one, am glad his zeal for completeness was contained within Thermodynamics, so we are left with _entropy._
With a BS degee in mechanical engineering I returned for an MS degree to see if I could get a practical understanding of the second law of thermo. The MS degree didn't help so I gave up after that. I'm retired now but I still wonder where the numbers in the thermo tables come from. I don't think my professors knew. And what does dQ mean anyway? How do you measure it? I've never seen a dq meter. Finally, how do we get from a thought process in thermo to actual numbers?
Entropy is NOT a measure for messines or chaos or et cetera - did Clausius really mean that with disagration??!! Anyways, great video with historical background - i expected such classes , i.e. with historical context , during my studies.
The electrical engineering curriculum at UPJ did not require thermodynamics in 1975 (yes, I know - Heresy!) We did have to take heat transfer which I found interesting but sometimes baffling with all the named "numbers" and such. EE's regarded thermo as the realm of ME's and was not to be concerned with. One EE prof dismissed thermodynamics with the statement: "Q you." Your explanation was eye-opening and quite enjoyable. It was so down to earth I think I about grasped it although I'm sure a host of ME's and CE's out there would deny the possibility of that. Thank you for taking the time to enlighten us.
If, as you say, Clausius read Carnot's paper in 1849, then Carnot, who died in 1832, could hardly be called "long-deceased." True, from our perspective in the next millennium, they are both long-deceased. But from Clausius' point of view, Carnot died when he, Clausius, was ten years old, hardly ancient history.
Excellent Teaching of historical information, but everyone is unhappy with the physics and science of Entropy, aren't they? If the QM-TIME Completeness cause-effect is why constants of logarithmic time-timing condensation sync-duration-resonance is interpreted as line-of-sight superposition density-intensity real-numberness here-now-forever projection-drawing Perspective, then there's the self-defining measuring problem that inclusion-exclusion timing-phase positioning of resonance bonding proportioning probabilities quantization identification is ultimately an i-reflection containment, closed system in which the entropic information is aligned with loop quantization properties.., so what fits where properly? This is why Quantum Tunnelling may be made equivalent to Sublimation or "one end" scalar density-intensity proportioning, of a resonance orbital-orbit, of radial=> radiation time-timing sync-duration spacing. Hypo cold-> Sublimation to hyper hot via Singularity positioning tunnelling. It is AM-FM Communication In-form-ation, holography shape-shifting. This is the old illustration job given to Apprentices, and the Master Artist illuminated the early stages to complete the project.., Geometrical Drawing and Perspective, that has always been Holographic Principle Imagery of perceived probabilistic correlations, in Completeness, artfully interpreted. ***** In short, Entropy is the 2-ness picture-plane chaos of cross-sectional disoriented axial-tangential locations, a matter of assessing transverse trancendental e-Pi logarithmic condensation. Look at the 6-sided drawing of the exponential curve from axis to axis in 3D-T Physics-Math to get the idea of conic-cyclonic orthogonal-normal Superspin vanishing-into-no-thing perspective.., and Entropy of resonance here-now-forever may be observed in the picture-plane. (?)
At the time of Clausius the understanding of atoms and molecules was very vague....physicists were arguing about the existence of atoms until 1906 ...the caloric theory created much confusion in the understanding of thermodynamics
3/3 Here is food for thought: In electricity flow we have I = V/R In heat flow we have T = dQ/dS (at equilibrium) S being entropy. The condition: "at equilibrium" is very important. Perhaps worth noting that Equilibrium Reversible is Not the same as Cyclic Reversible; they posit and imply two different contexts of operations. The analogy between R = V/I and S = Q/T is supported by the work of Lord Kelvin on the nature of heat -- the only such work ever done. Entropy as Clausius later recognized is in fact the resistance of the Transformation of heat into internal energy and from internal energy into heat. An analysis of the relationship between heat, the quantum magnetism of the atom, and the random displacements of atoms shows that entropy is not a measure of randomness or "messiness" as presented here. The Entropy concept became accepted by Lord Kelvin and others only after Clausius recast it in the context of "Transformation" of heat, and away from pure randomness. Also of import, the concept of randomness, such as may also be viewed as chaos, has now been developed under Chaos Theory.
Thanks for this video. I would comment that Clausius definition for entropy is empirical based (dS=dQ/T), while "Boltzmann"'s definition (S=k lnW) is based on probability theory, in which the number of microstates are needed (i.e. the number of molecule positions and movements that give the same total internal energy at equilibrium condition). A modern qualitative definition: Entropy is a measure of how much the (internal) energy of a system is dispersed. This definition is linked to Kelvins law for entropy.
I've never been quite happy with the 'laws' of thermodynamics - are they in fact merely axioms, like Euclid's, which have been rather undercut by Lobachevskian geometry etc.? - or Newtonian physics, now largely displaced by relativity? Do these 'laws' in fact withstand things like quantum theory - which is now accepted as rather more than 'just a theory'? I'm sure they do help in understanding and explaining some processes, but I get worried when people like Brian Cox start saying that 'x' is impossible because it would break the second law of thermodynamics (I'd be happier if he'd said 'x' is unlikely to be possible because... ) Thanks for the great explanation of the history though!
2/3 The Boltzmann Entropy is also not the same as the Carnot Cyclic Engine based entropy -- the Clausius Entropy; as formulated by Clausius. This has been a mistake that has been made for years. Boltzmann Entropy is calculated at micro-matter ( atomic) states while Clausius Entropy is calculated at macro-matter (Newtonian) states. The bridge between the two states of analyses contexts is Statistical Mechanics (or Statistical Physics). So the development of a physics entropy would have to pass through Statistical Mechanics to generate the Clausius Entropy and that is currently being done with Molecular Thermodynamics which extensively uses the Virial Stress Tensor of Clausius.
Heat cannot converted into work (mechanical work... is what is always implicit) Heat is converted in pressure... than in work... ;-) If the entropy of closed system can only increase... what happen when is at the max possible value? did it increase further?? ;-))
Love the references to the actual research papers. These are so cool. I have Dirac's seminal 1928 paper on "The Quantum Theory of the Electron." One of these days.... (and I can assure you it will take me a long time to understand the math (esp. the 4x4 matrices) but... I will be retiring soon)
Entropy is about the efficient conversion energy NOT order/disorder. This arbitrary definition was created by some creation scientists who wanted a facade of science over their religious theory. i.e. As organisms become more complex (evolve) they become more "ordered" counter to natural disorder and that requires some outside force, i.e. watchmaker, creator, etc. But as organisms become more complex they become more efficient and their entropy decreases! Consider the steam flowing through a steam turbine blade path. If the path is 100% efficient entropy does not change, Si = constant. But because of internal and irreversible losses the entropy increases. This fact is used to evaluate the efficiency of the blade path. It is obvious on any turbine cycle heat balance. inlet Pi, Ti, Hi, Si and exhaust Pe, Te, He, Se. Hs = Pe, Te, Si He actual is greater than Hs ideal. (Hi - He) / (Hi - Hs) = efficiency. Picture the upper/lower regions of the boxy Carnot cycle. Enthalpy is the upper area. Entropy is the lower area.
I truly do love the little lecture here. The detail is superb. Could S for entropy be because there was Q for heat (just quantity, in Joules' time) and T for temperature? U was used strongly by Clausius. Part of Clausius' problems were that he would not reply to **anyone**, either disagreeing, asking, or agreeing with him. As we all know, to get stuff published, an editor will ask for an independent opinion. Tricky if you stay in your ivory tower.
I heard that Schrodinger's quantum mechanical equation of probability waves is actually a heat equation so maybe work = heat, thus Schrodinger's equation's about work i.e. energy?
Many thanks Kathy. Really cool research , interpretation and teaching. Yes I was thinking about Boltzmann. Too sad he did suicide Will watch your video. Best regards. Js
Without question the finest history of thermo lesson I have ever witnessed. Add to that the *absolute clearest* explanation of the derivation and description of the 2nd Law. I will be looking for and using your videos in my Physics classes for sure!
