Confusion about entropy always increases

I like the way Baierlein (Thermal Physics p.44) describes it in my textbook: "You may, however, sometimes hear entropy characterized as 'a measure of disorder.' [...] The words 'order' and 'disorder' are colloquial and qualitative; nonetheless they describe a distinction that we are likely to recognize in concrete situations, such as the state of someone's room. [...] Imagine a bedroom with the usual complement of shoes, socks, and T-shirts. Suppose, further, that the room is one that we intuitively characterize as 'orderly.' Then, if we see one black dress shoe of a pair, we know -- without looking -- that the other shoe is right next to it. If we see one clean T-shirt, then the others are in a stack just below it. There are strong correlations between the shoes in a pair or the T-shirts on the dresser. Those correlations limit severely the ways in which shoes and T-shirts can be distributed in the room, and so the objects exhibit a small multiplicity and a low entropy. Now take the other extreme, a bedroom that we immediately recognize as 'disorderly.' If we see one jogger, we have no idea where the other jogger is. Under the dresser? Behind the bed? Lost in the pile of dirty T-shirts? And, for that matter, what about the T-shirts? If we see one on the dresser, the next clean one may be on the desk or in the easy chair. Correlations are absent, and the objects enjoy a large multiplicity of ways in which they may find themselves distributed around the room. It is indeed a situation of high entropy. There is usually nothing wrong with referring to entropy as 'a measure of disorder.' The phrase, however, doesn't take one very far. To gain precision and something quantitative, one needs to connect 'disorder' with 'absence or correlations' and then with multiplicity. It is multiplicity that has sufficient precision to be calculated and to serve as the basis for a physical theory." TL;DR. Order Strong correlation Small multiplicity Disorder Absence of correlation Large multiplicity

The only way this is helpful is that it makes clear I have no idea what entropy is.

Anyone worse off after watching this video? Or is it just me?

I think Brady has one of the best jobs in the world.

Entropy is the observable tendency of matter to assume the most stable state based on statistical energy distribution. Usually, this manifests itself as "disorder" especially when we talk about gases or liquids. The key thing is to get people to stop thinking of entropy as a force that "does something" (as too many professors teach in undergraduate thermodynamics), but instead as an observation or measurement that can inform us about other aspects of whatever we are examining.

And there's a little extra bit: kzfaq.info/get/bejne/o8eHqdqmvriYhnU.html

Entropy is a measurement of dispersion of energy in a system, an increase of entropy means that becomes more difficult to extract energy in a system, the appearance of order or disorder is irrelevant to entropy by example if you order all the atoms, particles and matter in the universe equidistant to each order, gravity cannot work, so entropy will be at its maximum but the universe will look very orderly.

Entropy isn't what it used to be :(

Great video, charismatic, engaging and concise delivery. Nice back story with the frustration over previous work and explaining flaws with entropy descriptions. Nice touch with the citations too. More of this please.

i think im more confused then ever

I'm a computer science major, but damn does your content make me interested to learn more than the required physics and chemistry. I really enjoy the quick education type of content on youtube, I can't get enough of it. I would love if you put an interesting math problem in the info section related to each video.

One way I think of it is like dropping a ball. Yes, there are thousands of directions the ball could go in, but it's always going to go straight down because gravity is acting on it. You always have to take into effect inputs of energy, because that wildly distorts the probabilities of one outcome over another.

Entropy is one of my favorite topics in Physics, and I haven't watched the previous videos on it. But very much enjoyed this one.

I love how Phil just gets up and struts around in his excitement xD Brady's camera is just all over the room

This video clarified the subject a lot to me. Thanks a lot Prof. for being so interested in finding the best way to explain these concepts to us, I really appreciate it.

So...entropy is basically the tendency of closed systems to form into more likely arrangements and not the tendency of closed systems to become more disordered?

now, here's a small problem, the entropy IS going up, but NOT in the crystal, it goes up in the entire system , which in our case is the universe if you would consider a smaller system, like an isolated room, with some ions inside, eventually the ions will clump together and form the low-entropy crystal, but that will ALWAYS release heat, and the heat will drive the entropy of the room higher, even if there's a vacuum in the room, the total entropy will still be higher because now the disorder of the energy inside the room is higher than any possible disorder the initial ions might of had

I’m seldom able to personally attach very much feeling or muster very much enthusiasm to any subject. I really like the way Professor Moriarty is able to convey his enthusiasm and sincerity about these subjects. It gives me so much value when I watch these videos

Phil, thanks for persuading Brady to pursue this. As an Armchair Physics fan, I've been researching terms like "Does Life = Negative Entropy" precisely because of the Entropy Confusion that you explain here. I've looked into Shannon's Entropy with regard to the number of bits of information and followed it through to Lenny Suskind's lectures on Black Hole Entropy and it all seems at odds with the laws of thermodynamics and Brian Cox's sandcastle analogy. Sure, there's a grey area for for popular science and there's a definite area for career scientists, but there is a middle ground for folk who want more than BBC science, hence why we turn to you guys - please keep pushing it the direction you're going as it is great to have people who really know their stuff impart their knowledge at a level beyond "6 cans of stella and a chicken tikka" level - there is a thirst out there for grown up science and I love the fact you are willing to give us that - well done you!

how about a series of videos? Entropy is a pretty interesting topic and, as shown in this video, seems to be pretty complex too. A few more videos into that might clear things up a bit for all of us

So what is entropy _really_? Apparently, the answer is "it's complicated."

I am so happy to see another video on entropy. This is one of the most difficult concepts for most people, due to all the reasons he went over (the oversimplification of entropy as order versus disorder is probably the biggest culprit). Thank you Phil and Brady!

THANK YOU! The order-disorder description of entropy has made me uncomfortable for so many years, but I keep hearing people defend it. I understand how it's a useful tool to casually explain to someone unfamiliar with physics what entropy is -- especially because entropy is so complex -- but while it's a handy intro to the concept, people are often given only that explanation, and in that situation I've seen it leave too many people with really bad notions of entropy that they use to convince themselves of very wrong ideas. I'm really glad you made this video. You have a chance to get a lot of vision on this issue with people who wouldn't otherwise find out about it.

Start again from scratch! Make a THIRD video. Do not apologize for, or refer to, the first pair of videos. Take a deep breath, figure out what the hell entropy is, and then explain it to us well.

Love this guy! Great respect for his passion for science and explanation.

I just want to say the coverage of the various topics, though brief, is informative and intriguing. These video shorts have piqued my interest and have been the impetus for a number of follow-up searches (by me, of course) into the myriad of subjects covered. Thank you, to all contributors, for sharing and I certainly am looking forward to the many left to watch. Keep up the fantastic work!

Thank you so much for providing the videos and website. 60 Symbols really makes a difference for those of us on the outside looking in. Very accessible.

'This is from a kid's crystal growing kit'. Unless it's in my hands, and then it becomes an adult's crystal growing kit. :)

Brady you made a video for PeriodicVideos a few years ago called "Becoming a Chemist - Viewer Questions". It would be interesting to see a similar video for SixtySymbols.

This video made me cry. I have finally understood entropy. Thank you, professor

Thank you Professor Moriarty for following up on this theme and unpacking the complicated feature called entropy. Thanks Brady, you ask a lot of good questions as well for the layman like me. Another thoroughly enjoyed Haran video!

Isn't the concept of order an intrinsically human thing? I mean an arrangement of particles that can look disordered to us might have an underlying order that isn't obvious to a human observer.

continue to fight entropy every day gentlemen! i'm 100% behind you!

Thank you. Thank you for all you videos. They are empowering. I ponder entropy all the time. And starve for higher detail.

You're like the first person on the internet to clear up this confusion, thank you.

Yes! Finally a video saying entropy is not disorder

I must bookmark this video for the next time I encounter a creationist who cites the second law of thermodynamics as a "refutation" of biological evolution.

This video helped understand entropy so much better. Thank you professor!

Thanks for making this video, I've been aware for a while that describing entropy as a measure of order is very misleading. Describing it as the number of ways you can create a specific state is a much better way. Glad this video was made.

"AAAAAAAAAAH" - Me after trying to understand this video

this guy loves what he does. always energetic

I am so glad that this video was made! I have been arguing for not using disorder to describe entropy for a very long time! Thank! (I might even have made a post in the past one of these videos about it)

This video really captures the essence of what science is all about: modeling the real world, trying to understand how things are related, and continually revising your understanding to better fit with the evidence. Things may be complicated and difficult to explain, but that just makes them all the more interesting.

I think the vid's title is appropriate - my brain system is closed and in a high state of confusion... time to do some reading on this.

Why do your headphones always come out of your pocket tangled? Entropy! Shoving them in there and walking around in effect randomizes their position. Since there are far more ways to tangle a string than there are to keep it perfectly coiled, the odds are your headphones will come out tangled.

I've been introduced to chemistry in high school and in college. So, I have a general understanding of entropy and enthalpy. I was interested in the scenario where entropy resulted in a more ordered system. I would be happy to sit and listen to a full lecture, and / or future videos on this topic.

I've missed videos with Phil! Like him the most

I'm betting that someone is going to turn this into a religious discussion.

Hmm I can see the guy is passionate about th topic. The message however is a little difuse, maybe making a video with a little more preparation and focus on the message could be considered.

I worked in the nuclear industry as a radiation control technician and learned alot about the nuclear world as it relates to radiation and atoms. But listening to yall I realize just how much I love science. Even though im not a scientist, my degree is in operations and project management, I have learned so much from your videos. Please keep up the awsome work you are doing it is wonderful.

I have to say I'm finally very happy about that explanation, professor Moriarty. That's what I'm always saying: one cannot understand entropy without the Gibbs ensemble, because it's all about the number of microscopic representations of a given macro-state. I would add to that, that if ergodic hypothesis is satisfied, so the system is exploring every micro-state with equal probability making the time averages equal to the ensemble averages, the second law of thermodynamics becomes a trivial statement. It simply means that the system will evolve to a more likely state, i.e. having more microscopic representations. I think you explained very well what the entropy is exactly, formula and all. Thanks.

This is what I find hard to grasp. If heat promotes entropy, how is it that our current universe, which is colder, has a higher entropy than, say, the universe when it was a few microseconds old (which was hotter)? There should be more ice crystals in the universe now than a few seconds after the big bang. If the universe is in fact a closed system, that's expanding thus making heat be less "potent" how is it that entropy increases within it?

I love this man!

me and many others use the term rejuvenation with the body to stop entropy...giving the system as a whole what it needs to function correctly, while removing "obstruction" so you dont have continued entropy in weaker areas of the body ....very neat to watch this discussion and see all the ways we can figure out what happens on this rock floating thru space....

Thanks for setting the record straight doc!

I'm not sure that was a better explanation.

I'd love to say I now understand more about entropy than I did before watching the video but the explanation here appears insufficient to me.

As someone who just spent something like 6 or 7 weeks of P-Chem this whole video, and Brady's questions in the video just make me smile because of how complicated and interrelated all of the thermodynamic values are.

I love Professor Moriarty's energy when he does the videos!!

So entropy is..............

mr moriarty really got old in the last 6 years. (but he aged well, so no offense)

Thank you for the excellent video. It's enough just looking to the universe to see how order is dominant, as the things are growing in complexity.

Thanks for making these videos! Fascinating stuff; keep it up!

I hate how he keeps having to shorten what he's saying, I wish he could just have all the time he wanted to explain this concept as much as the average person could understand.

Explanation isn't very satisfying.

The description of Entropy being described as the number of ways a system can be arranged is really what made this click for me, what used to throw me is that it's said the universe is constantly moving towards entropy (which is regularly used as a synonym for disorder) but in the heat death of the universe, all energy will be uniform, those 2 statements used to seem highly contradictory to me but I think I see what's meant now. Hopefully I have a correct understanding of entropy now, even if it is a minor one, thanks for the re-do of the video.

we had a lecture about entropy today, and so many minds were blown.

I like this bloke - he gets [k]narked quite easily and the more of his videos you watch, the more things you discover upset him.This is thermodynamics for you - even the vaguest understanding of just the tiniest slice of the subject can leave you quick to ire and grossly upset your otherwise gentle condition.

I still find entropy a very hard concept to grasp for a simple mind like mine, fuzzy analogies definitely don't help. But in the bright side, as I keep trying to wrap my head around it, I get a good excuse to revisit Professor Moriarty's videos, which is always lovely!

very clear and understable video, good work.

Ways... that is a great way to visualize it. I think I will keep this in mind next time I get that blank look when I use the word "entropy" in the real world. Seems like a much better way to illustrate it to people who haven't heard of it before. Good vid :)

I prefer the strictly statistical-mechanical interpretation of entropy, as you showed at 7:07 : it is the logarithmically scaled form of the number of microstates of a system. That is, the number of ways a system can be arranged. "Order," however, is almost entirely a perceived (not actual) value. For example, most people tend to perceive a glass of water as being more "ordered" than a glass of crushed ice, yet the glass of water has higher entropy. We are unable to perceive the information stored in the motion of the particles (liquid water as opposed to ice), so it does not fit into our concept of "ordered" or "disordered" system, and therefore fails when describing the entropy of a system.

I saw him pull out the soccer balls and was like "oh no, they're gonna argue again..."

Why can't more of my university professors be like the guys on Sixty Symbols... Amazing once more

I love how intense Moriarty gets about things in these videos........it let's you know he really cares about what he is explaining

I find the videos on entropy to be very interesting but to complex for the format of video that you guys keep releasing. Would it be possible to do a series of videos that explain the base models all the way up to the full complexity of entropy and disorder?

I don't understand why people find it so hard to understand entropy. The second law of thermodynamics implies that the total entropy of a closed system always increases. It doesn't say anything about the entropy content of individual parts of such a system, who are free to rid themselves of any amount of entropy they wish, provided there is a greater increase of entropy somewhere else in that system. What is so hard to understand about that?

People who are confused should read Isaac Asimov's "the last question" and for young people Diane Duane's "Young Wizard" series does a good job of, at the very least spurring interest in scientific ideas and especially entropy. Anyway, as I understand it Entropy is the theory that all closed systems in our universe (and ultimately our universe) trend towards their lowest energy state - aka the heat death of the universe. To me it has nothing to do with order or disorder but simply the amount of potential and kinetic energy locked in a system. The final state of entropy then is ultimately like when you run out of moves in Mahjong or Solitaire - there is no more possible interactions in which energy can be stored or released and in fact. In that way, in my mind, entropy leads to the most stability and so in that way, the most ordered universe possible.

I think the best way to explain entropy, is by first explaining the concept of the Gibbs Free Energy, and what it means about a system then introduce dG = dH + TdS. Because then dS can be related to its dependence on the temperature. The throw in how with the temperature and the energy flow in the system things either adopt a ordered or disordered state. I don't know but I will look at those papers for sure.. great topic this one

Brian Cox did a wonderful job explaining entropy in his series Wonders of the Universe. He explained by making a sand castle in the Namib desert. There is always going to be a lower number of possible configurations where the sand retains the shape of the castle, rather than the sand just being scattered in dunes.

Love this guy! He's just incredibly passionate !!

I enjoyed the S=k log W where W stands for (number of) ways. In short one could say Entropy is a macrosopic property that quantifies at thermal equilibrium the number of ways energy can be distributed over the entities in a homogeneous system.

About bloody time Brady! Sixty Symbols all the way. Love hearing Prof. Moriaty rant.

So is entropy related to the number of different spatial positions a molecule can occupy? In the paper from Lambert it is mentioned only that the energetic micro-states are important, I think (so molecule velocities, vibration frequencies etc.?). So which one is it?

I did wonder why there wasn't much mention of the energy part in the last video. I remember reading an excellent description that made perfect sense to me--you can tidy your house and put everything where it belongs, thus putting the objects in a low-entropy state, but the energy you took to do it, the biological energy and heat energy and mechanical energy and so on of you moving and putting those things in place, that still creates an increase in the overall entropy. You're burning energy in your muscles, exhaling CO2, radiating heat, and so on--that creates more entropy than what you took away by putting everything away.

Brady, may i suggest prof. Moriarty make 2 or 3 videos on entropy one for beginners, one for people who took physic after high school and one for experts like his colleges in non physics areas like professional researchers and scientists. i can see that he wants to talk about more advanced topics but doesn't want to confuse everyone. Love the Video!

I just read the paper. Perhaps a better analogy would be that soldiers at a parade represent a low entropy situation, whereas people in a piazza (imagine people walking across the piazza in all directions at different speed) represent a high entropy situation. What about that?

I've just watched your entropy videos and I was wondering, you said in your first video as time goes by the entropy of a system increases and it's incredibly difficult to reduce it but in the video simulation from the group at Michigan they showed the system getting more ordered and I'm a little confused what happens to entropy over time?

Moriarty is back!! Love it!!

I love how Prof. Moriarty has all these props around his office for demonstrations =P

Naive question: if the entropy term is multiplied with the temperature, does that mean crystallization is "allowed" to produce an ordered structure because it gives of enough heat so the entropy of the system as a whole goes up? i.e. crystallization, e.g. when a slab of steel solidifies in a mill, gives off so much heat because the structure it produces is so ordered as opposed to a merely very very hot liquid cooling down to a much cooler liquid. Or did I misunderstand something?

great video and explanation! Thanks guys

Mission accomplished - I am now more confused about entropy than ever.

Thanks for clarifying the "parameters of the parentheses" of science ;)

You two should do a podcast because I could listen to you both all day

I feel like the video cuts off right when we're getting close to having a sufficient picture of actual entropy leading to situations like spontaneous crystalization or apparent 'order' from 'disorder'.

Blue Snowball in the background :) I think you should do a feature length episode on entropy. There's so much that Prof. Moriarty seemed to want to say about entropy that didn't make the cut in this video (or the last one for that matter). I think entropy is one of the most interesting topics in physics.

I have been saying this for years! I need to meet this Lambert, I think I would like him. I think there's one thing Dr. Moriarty misses here: the main reason that the "disorder" explanation confuses people is that they already have preconceived notions of the idea of disorder. Further, so many people trying to teach the subject neglect to mention that saying that entropy is a measure of disorder _only works as an intuitive explanation for systems of particles_. It's very simple: entropy is a statistical thing, as described at the end of this video. Teach it like that, and the confusion goes away.

Dr Moriarty, I have a question, where can I get some information (book or paper) in wich I can se the relation between a hard sphere model and the entropic part of the system?, I'm a physicist myself and a derivation of this relation will be extremly helpfull to me, so a pretty technical source will be perfect to me, and very informative. In advance, thanks for all.and sorry for the bad orthography.