Entropy - Professor's Response
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- Опубліковано 3 сер 2009
- Professor Philip Moriarty responds to comments made about his original entropy video.
The original video is here • Entropy - Sixty Symbols
Check out all our phsyics and astronomy videos at www.sixtysymbols.com/ - Наука та технологія
Entropy isn't what it used to be...
Did people really take your analogy of the students in the common that literal? That's just absurd.
Who on earth would NOT get that the students example was an analogy and it actually explained the arrangement of gas molecules...???
David Greene I've no training/school in the topic and I totally understood that Professor M was using the students as an analogy. People do that sort of thing in many situations. It's just that so many lately are so absolute in terminology. Life isn't black & white, there's a whole lot of grey and color too. 😉
Idiots!
I love these brief videos and it's galling that you get a hard time from people who expect more than a five minute video can deliver about complex topics. The best you can do is to stimulate our interest so we can head off to read and research more in books and online to the depth of our interest. Thanks for supporting this initiative Professor.
I think that it is definitely fair to say...
That the video on entropy generated a lot of heat!
Nerds, nerds everywhere. Is this heaven?
get out ahaha
And not so much light?
Please, don't cut out so many parts then, I'd love to watch longer videos!
Just want to let you know how inspiring these videos can be. I am in my final year of undergraduate school in physics because of these videos and videos like it. I appreciate the brevity and the casual nature with which these concepts are discussed. It makes them much less intimidating and sparks just enough interest to want to know more. If you still read the comments, know we still appreciate the videos!
I have indeed seen the longer videos on your channel, but between the short ones and chasing up paperwork I've not yet had the time to watch them. They do appeal more to me however, as they will undoubtedly deliver the detail I desire.
I fully appreciate that there's only so far physics can be simplified, which is why I generally look for the longer videos, and now it seems I've found a good source. Thanks!
Love to see ur dedication towards making these videos, even made an effort to make a response video to further explain about the topic when you see than viewers don't get quite the right picture! Two thumbs-up! ;)
There was no real mistake in the previous video if you ask me, if someone actually confused analogy with what actually happens, simply that person didn't get the video at all. BTW Prof. Moriarty, I want to thank you for this videos, are extraordinary and I really admire to see all the passion that you put into the subjects, thanks a million.
Would pay to have Moriarty lecture 😍 his explanations with music bs are so amazing!
Sir, if you have the time please do longer videos, I would totally watch them since these are very educational :)
this guy is my favourite on the channel by far. his enthusiasm is contagious
You guys rock, keep making these videos, they are just so good to pass the time and enjoy some slices of science.
I fully agree about Boltzmann - as I'm sure you know, his headstone is engraved with S=KlogW. I think of Clausius for the 2nd Law of Thermodynamics, and if explaining the concept of entropy can be tricky, the concept of a closed system also escapes many people.
But most importantly, thank you - it's always good to see academics in any field being accountable for the things they say, and the Nottingham Science video series are a great resource which just keep getting better.
The fact that you are making videos that help to spark an interest in science in people is whats really important. There are those of us out there that know certain points are glossed for a reason :)
A very humble, well mannered video. Thanks guys
I love these videos. we need more professors like him out on youtube!!
I really appreciated the the explanation differentiating card-positions from gas molecules. I've never like the "Messy Room" analogy for increasing entropy, and this succinctly explains why. As explained, it's important to distinguish analogy from reality.
Absolutely. I really would like a completely uncut version of anything Phil has made.
I wish there were more professors like Professor Moriarty teaching in universities. If you see a teacher so passionate about teaching, you can't help but get passionate in studying.
The way I see it, Carnot developed the equations for bulk (thermodynamic) entropy.
Boltzmann developed the statistical mechanical definition that, of course, is tied with quantum theory. His definition had the ability to define entropy at the atomic and molecular level.
I love how Professor Moriarty really gets into his physics. I would love to take a physics lecture series under the tutelage of professor Moriarty.
I think that there should be a channel which has hour-long videos in lecture format on the symbols. Call it "Sixty Symbols Extreme Edition"
Your right the system in question is the earth and JLConawayll correctly pointed out that its not closed. I meant to say adding energy to any system doesn't necessarily cause entropy to decrease
Loving the perpetual motion man on the shelf in the background!
@Busticate
One could take it that way in a vacuum or in a "natural" state. But uncertainty is rather simplistic. In his analogy everything is in and of itself within finite parameters like a vacuum tube. Expanding or separating from a finite point to a certain larger point. Although keeping the same thermal energy as originally had, It becomes diluted because of the distance of travel in which to reform. Which means it succumbs to inertia in order to come back together. Thoughts???
Well, for one, the analogy was perfectly clear to me. I recognized it as an analogy where the professor was using a more easily conceptualized item (a body of students in a yard) in place of a more abstract and ambiguous example (energy in three dimensional space) that may have served to better illustrate his point.
I just want to say, Professor Moriarty, I think your segments are great and I always enjoy them and learn a lot from them. :) (That's not to say that I prefer your segments over any other Professor's. I love learning in general, even if the topic in question is way over my head, and I believe that learning is a privilege an more people should treat it as such.)
I like how the book Chaos is thrown in a pile on the bookshelf and not in an orderly row with the others.
One of my favourite physics guys on Brady's various channels.
Another way to think of Entropy is that it is showing organization on a scale. A solid object has low entropy, like frozen water, ice. Then it melts and the entropy becomes greater, but it is greater from the perspective that it is observed from. To the individual water molecules, they are very organized Viewing all of the melted water, puddle of water, as a whole looks chaotic because you can't track what each individual molecule is going to do and how it will act. It shows the change of organization within the states as they change.
This man is a legend.. and as a fellow celt and first time poster i feel inspired..
I like the fact that you read every response. That is the mark of a good teacher. I teach Developmental Mathematics. You sir are a role model.
Prof. OOm
Brady,
Would it be possible to release full, unedited videos of the various professors? I think a great many of us would absolutely love the full-length videos!
In my studies, I've realized that when passionate professors are allowed to talk their mind for extended periods and outside of the lecture, A LOT of amazingly interesting information and details come out.
Please share with us the full videos as well! Maybe a separate channel?
You already mentioned the staying the same part, so once they reach the maximum entropy of the system they will remain in that state until energy is put into the system or further taken out of the system. The part about the probability (given enough time) is a quantum mechanics concept which generally doesn't play well with classical theories like the second law of thermodynamics. Honestly the best answer I can give for that.
I like the analogy I thought of, of a giant billiards table where balls don't loose any energy as they bounce off stuff. So when you break the neatly clustered pack (low entropy) it causes the balls to start bouncing around everywhere and become chaotically dispersed (high entropy). After a billion yrs of bouncing around randomly, eventually, the balls will -by chance- collect in pack formation temporarily before going back and just continue bouncing around.
Youre doing a great job guys, keep moving forwards!
Thermodynamics/mechanical statistics CAN be used to describe non-gas/non-quantum systems. I've seen papers that use it to describe culture and deduce some properties. There are also very interesting papers on how to calculate properties like energy and entropy from markov chains, this is very interesting because markov chains are very general, so if you pose the problem right you might be able to talk about the entropy of the students as he said in the video.
Of course, there are systems that don't behave like physical systems so you cant apply the same laws, the students for example very orderly go to the cafeteria on their own around lunch time, so you can actually gain information as time evolves, this doesnt happen in plain physical systems unless you perform measurements, but just being able to talk about the entropy of a system of students at lunch time is very nice in itself.
Cristian Garcia when I was at high school, our physics teacher (7th day adventist, that's important for this story :) ) told us that because of the Law of thermodynamics and entropy, evolution is not possible. He said that if systems gradually collapse then there couldn't be any particles merging together and creating molecules. I'm not a scientist, but I think that he was mixing up two completely different things in one (as some religious people do). Would anyone help me out here with explanation?
+William White Or the contrary : as gravity (matter) increases, order comes into bricks, that is things fall together in the gravity well and, at high gravity levels, atoms don't exist anymore, just a neutron soup (tormented but regular) that holds most of the gravity.
Of course the Solar System is losing energy : that's what has been powering life on Earth for the last billion years or so. The Sun (99% of the system) has been heating up Mars, powering up Venus, sustaining life on Earth, just because you're on a planet doesn't mean you're average....
The reason is because entropy is the result of the molecules moving and bouncing off of each other at random, then moving in a straight line until they bounce off of another molecule.
Because the group of students doesn't behave this way at all (students don't move in straight lines or bounce off of each other), its only useful to envision a cluster of molecules (low entropy) moving to a dispersed gas (high entropy)
I'd love to watch Professor Moriarty's lectures on thermodynamics.
presuming the compression of a gas in a container generates heat by the compression, & the compressive force being kept on acting against the atoms, these atoms moving constantly under the force, do they continue to generate more heat during the continued compression?, or is there a cut off point.
Thom in Scotland
I think because of the reasons this particular video was needed in the first place...
Without the whole picture of a whole college curriculum, the deeper you go into any one particular subject, the more other questions you open up.
It would balloon real fast, I would think.
Ok, I've watched this video over another 2 times to try to understand a bit better. I'm no physics major or physicist by any measure just an enthusiast. But to answer your questions I would say after the first video my understanding of entropy was the tendency for particles/elements/things to move from an ordered state to a disordered state. I think it's important to note that you have, as you mentioned, simplified the meaning and this video demonstrates that the full meaning of entropy is ...
These videos allow me to quench my appetite for hard science without having to sit in lecture for months and break down complex mathematical laws.
These Sixty Symbol videos and the Periodic Table of Videos are amazing, simply amazing. Once I start watching them, I keep clicking on the next and the next, and suddenly an hour has gone by.
You're doing a fantastic job of squeezing the tasty juice of these scientific concepts down into 5 minute shots, and I applaud you for it.
Don't worry about the haters and the trolls - they're like background radiation, always there. Hopefully we can just get our signal above their noise. :)
@danielbluesmoke I agree entropy does most certainly heavily rely upon thermodynamics and spacetime itself up, but if the second law of thermodynamics stays true no matter what then with the arrow of time what happens when you go in "reverse" if that makes sense?
this explanation helps clarify entropy so thanks! as someone with zero knowledge to begin with, every little bit of information helps. the sixty symbol videos help to raise scientific literacy among lay folks like myself. please continue or all we will have on youtube are music videos and home videos of our cats doing funny things.
hey... can u also give a lecture on isentropic proces???
I think that I would love to have Dr. Moriarty as a professor.
It would be nice to have a video on the difference between the Clausius, Boltzmann, and Carnot definitions of entropy.
I also think it would be great if you did a video for thermodynamics, describing the four laws and maybe explaining the basics of how heat engines work. Another suggestion would be a video comparing thermodynamics to statistical physics :)!
I notice the professor has a copy of James Gliek's 'Chaos', very interesting. Would be interesting for his view on how the universe isn't actually governed by Newtonian laws and normal distributions but rather non-linear dynamics with exquisite dependence on initial conditions.
How much do the definitions of entropy and the laws of thermodynamics need to be modified for quantum mechanical systems?
Also, is Rush's Clockwork Angels the best album ever written or the best album ever written? I know I always want to design heat engines the moment the opening riff to Caravan kicks in.
I see your point, but I still think it's better than an edited version which leaves me more confused than I was before I began, prime example - entropy. The definition I go by is essentially the "waste" energy in a closed cycle thermal system, because that's what's more appropriate to my field. Then I hear there are alternatives, and after getting through the analogies it made less sense. Had you gone all the way, without having to resort to analogies, it would have been longer but clearer.
In geology entropy is brought up as how minerals and rock cristalize. Basically, the more energy the less order. (lava is chaotic, rock is orderly) To get everything arranged (cristalized) the energi must be lowered. Hower, the paradox is that the re-arengement requires energi so the lowest entropy can never come to be: for ions to form a cristal perfectly the energi must be low to not knock them around, but they need energi to get in the "right" place. Thats how I understod it XD
Entropy applies to everything but the links to order and disorder only work at the atomic scale. Classically, entropy is something like the capacity of a system to do work, which decreases over time because energy is lost as heat. Boltzmann linked this to the distribution of molecules in a gas and defined the entropy in terms of the number of other arrangements that would have the same physical properties (e.g., temperature, pressure). It turns out that the two definitions are consistent.
Well to me it became perfectly clear that it was an analogy from the first video, but i happen to study physics in university so i am used to the way physicists use analogies to put across such concepts as entropy etc. (i hadnt been taught entropy in university at the time i first watched the video, i was taught entropy in my thermodynamics course last week so i came home and rewatched it).
hey! brady!!! thanks a lot man!! these videos are just awesome!!! and thanks to all those physics passionate people!!
@velocity73R room temperature in Celsius or Fahrenheit?
I would give a great deal to be able to pick Professor Moriarty's brain for an hour. (Or any one of these marvelously intelligent and personable educators for that matter!)
Wait... I have been watching these videos for hours, fascinating stuff, and I just realised that this man's name is Professor Moriatry? As in Sherlock Holmes's archenemy. That is awesome.
I've always thought of high entropy as being similar to "chaos", while low entropy is similar to "order". You cant really use people or vases as examples, because they are only on two planes. A drop of milk in tea is an alright example, as would be poisonous gas in a room full of air. The gas disperses, and there is a very very miniscule chance of it reforming together in the room.
Good Job Prof! I love this channel.
I think he might be one of my favorite scientists on Sixty Symbols. And his glasses are cool.
i always think of entropy as the impossibility of perfectness in a universe ruled by gravity. If all matter was perfectly arranged (equally spaced in between) no entropy would occur. And it is because of the impossibility of perfectness (in this universe) that some form rearrangement of mass occurs. I guess you can also apply it to other types of energy (bosons or whatnot).
ive watched this and the the original video a few and times and realized him using the students as an analogy was just just that, an analogy
Thanks a lot for the video. Best wishes.
I do the same thing when I teach sometimes ... part of it is probably the passion we have for our disciplines, and part of it is the excitement, I'm sure. But do you ever get scared that an idea that you have in your head will evaporate before you have time to verbalise it? I always have. I wrote a supervision paper applying Heisenberg to this in the context of being dyslexic when I was working as a research technician in a medical physics & clinical engineering department at a hospital in 1995.
Do interactions between living systems cause increase or decrease in entropy?
The deck of card model of entropy, by the way, comes from Arthur Eddington, 1928; see the eoht wiki article Shuffling cards model of entropy. As you have a dipping bird on your shelf, you might also like the eoht wiki article drinking bird, the thermodynamics of which baffled Einstein in 1964.
a fine clarafication and great insight into relaying knowledge and a passion for learning. (btw has any one ever asked for LESS beer?)
Just wanted to say ''thank you all at Nottingham Uni & Sixty Symbols'' for making me love Physics, Mathematics, and Science in general.
He's a professor. He's called Moriarty. How come he haven't appeared on a Sherlock Holmes movie yet?
By the way, you (both Moriarty and Brady) are awesome, I'm shocked as to how good these videos are, not only to pass the time, but also to learn new things (and especially for this, actually).
Good job, and continue doing these, I think I speak in the name of everyone here when I thank you for that. :)
Interesting insight, thanks
wow top notch. i didnt realize the professor reads the comments. he must have eyes of steel. respect++;
Also, I've seen an analogy of a sandcastle being built, and the way it erodes over time being used. Packing the sand, organizing it, then natural erosion simulating entropy. However, while the system of the sandcastle was being made, we were disordering another system. Earth. While the castle erodes, the earth becomes more organized, if only slightly. Can anyone clear all this up for me? Even beta decay seems more like ordering a system than disordering it. It all appears to be about balance.
We *need* to see the hour long videos!
hehe noticed the 'freon' bird ....
the sipping in the duck in the back is awesome :)
I found this very interesting since i haven't heard of this before.
I love how the drinking bird is bobbing in the background.
@ Phillip. I see the EXACT right book for making this video even more awesome! My Thermodynamis prof used the word CHAOS all the time to define entropy and made some quite funny and intelligent analogies using this.
It's right behind you on the shelf, haha!
Moriarty, to update you, regarding your comment *Concepts of entropy [only] apply to gas molecules; you cannot say that a particular arrangement of students has a thermodynamic entropy, German mathematical physicist Wolfgang Muschik, senior editor of the Journal of Non-Equilibrium Thermodynamics, has just commented, see threads below your eoht article, on your view, that *Yes, you can: If you have a certain defined distribution function related to these students, you can define an entropy.*
There is a second channel where he does post the extended footage for most of his videos, but not all of them. Go check out nottinghamscience and see
@danielbluesmoke the cards case is interesting... Suppose you want to recreate a former arrangement. In such case, the ordered state would be a no-brainer, and every other scenario would require complicated comparisons and memory usage. If I'm not completely off subject, resetting the cards in an ordered (i.e. aligned) state requires less energy.
Check out William Sidis and his theory on human activity as a reversal of entropy.
i am more familiarized to clausius and carnot cause my engineering book talk about it more than of boltzman, thou a more physics only orientated book has more depth in matters of information, thou i am studying engineering i find physics carreer very interesting, i really like ur videos.
bradey, and by extension, if your a professor, you probably have a PhD, Dr. Bradey! Your videos really opened my eyes to a lot of things, that had knowledge of them, but was never really interested in them. The concepts weren't alive, but because of your videos, they are and thats awesome. Thank you, and keep doing it!
The difference between an analogy and what's really going on . . . it is comforting to know that people this awesome have the same problems the rest of us have. It is the difference between linear and non-linear thinking. By the way, is that CHAOS, Making a New Science by James Gleick back there on the bookshelf?
Moriarty is my favorite of the 60symbols professors. :)
Same here! Irks the crap out of me, if I'm honest about it.
What guitars do you use?
It would be pretty cool if there were a second channel for those hour long videos unedited.
Leonard Susskind when talking about the Entropy of Black Holes said that "anything that has Energy and Entropy has a temp or basically Temp = energy/entropy. From that statement you could have entropy without energy involved? But doesn't energy have some expression in every equation. I guess my question is how is Entropy different from Energy?
Credit where,Credit,is due.Love this speaker of truth.Kind Wishes,from Leeds.
@RainbowDashXSyndrome yes it will according to the laws of thermodynamics when you have something unstable and uncertain it would give out kinetic energy cause if of the expansion of particles ;)
I've got an idea - you can have Brady post the unedited footage of all your ramblings, tangents and off topic discussions, in the same sequence as they were filmed. I for one would really enjoy watching the full explanation, as long as it may be, as it's not every day that someone spends so much time explaining a complex topic. Having the technical explanation edited out to suit the general youtube audience is a real waste if you've already put all this time in.
Well I think there should indeed be more beer with lectures. There was a series of lectures here called something like "science in the pub" that was an open science lecture in a pub setting with questions at the end. They were great! It was how I first heard about the expansion of the universe increasing when a couple of cool guys from the Anglo-Australian observatrory did a lecture.
I only had Non-Calc physics 101 and 102 but even I know that, in the end, entropy wins every time.
I couldn't stop staring at the drinking bird on the top of the shelves. :D
Anyway, I picked up on the fact that he was making an analogy, and when he says that he was thinking of gas molecules as he was talking about the students, that sort of had a bell going off in my head, so I think the first video was good enough. Making things even more clear never hurts though. :)
something much larger. Your comments about the cards and thermodynamic entropy probably made better sense to physics majors which is where it tripped me however reflecting on it more I believe my new understanding of entropy is that it is the measurement of the tendency for elements to move from an ordered state to a disordered one. My further interest would be how this is understood in the sense of the universe expanding and entropy expanding if it appears to be gaining form or is it.