Sixty Symbols - 2014-11-03
Professor Phil Moriarty talks about Entropy (again). Reddit discussion: http://redd.it/2l6ekd A little extra bit from this interview: http://youtu.be/maWvwuYR4VA An article Phil wrote after this video: http://physicsfocus.org/moriarty-confused-good-learn/ LINKS TO MENTIONED VIDEOS & RESEARCH The first entropy videos --- https://www.youtube.com/watch?v=lav6R7PpmgI and https://www.youtube.com/watch?v=av8aDFFtSs0 Daan Frenkel: http://www.ch.cam.ac.uk/person/df246 Sharon Glotzer’s group: http://sitemaker.umich.edu/glotzergroup/home TEDx talk from Glotzer: https://www.youtube.com/watch?v=chS8dpGB0E0 Disorder: A Cracked Crutch (not free to read): http://pubs.acs.org/doi/abs/10.1021/ed079p187 Visit our website at http://www.sixtysymbols.com/ We're on Facebook at http://www.facebook.com/sixtysymbols And Twitter at http://twitter.com/#!/periodicvideos This project features scientists from The University of Nottingham http://bit.ly/NottsPhysics Sixty Symbols videos by Brady Haran A run-down of Brady's channels: http://bit.ly/bradychannels
The only way this is helpful is that it makes clear I have no idea what entropy is.
I will!
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
this really helped ...... thanks :)
How does order come out of entropy in this analogy? The messy guy tosses his shoes around and sometimes the two black shoes wind up next to each other by chance?
@ceruchi Imagine that the shoes have some sort of adhesive between them so that they stay together once they end up next to each other once.
This is, I think, how the forming of crystal structures (i. e. chemical bonding) works: the electrons in the free moving atoms have more energy than those in the bond, so if two atoms interact (i. e. happen to be next to each other), the chemical bond is created while the electrons give off that energy as heat.
That's also what happens when some thing burns.
@δτ The guy has OCD and allways place the items in the same way.
@David Arnryd Basically, yes.
Anyone worse off after watching this video? Or is it just me?
Remember Socrates
"worse off"? Nah I feel fine. 🤷♂️
This video clarified a lot for me.
Entropy isn't what it used to be :(
Entropy isnt' waht it usde et:b (o
I see what you did there.
That's right... because it's always increasing! (ha HA!)
@Kemanorel Kin You dont see what he did there, its already gone.
i can't see what he did there
I think Brady has one of the best jobs in the world.
i think im more confused then ever
That means you understand it better than you did before
So what is entropy really? Apparently, the answer is "it's complicated."
@Penny Lane Actually didn't read whole thread. Most of the ones seem to ramble on about complication that I didn't even notice some of the better answers.
My answer is, the "lack of an equilibrium" which is just as confusing as this video.
Thermodynamics says that everything in the universe strives for an equilibrium, the opposite of that is really, chaos or entropy.
@SillyPutty125 +1
@John Redman
Removed because: OT and language.
@John Redman Yeah, well. Believe it or not, some people don't care about someone's shirt either way. I just saw that you were on a crusade and I don't want that here and it is also not the place. No good would have come out of it. There are no moderators on Youtube but now there's at least the possibility to keep your own threads free from the worst crap. You, unfortunately, chose to post something in that category.
Now please, go back on topic or go find some other place for your campaigning.
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.
I don't know what that means. I'm legit asking out of curiosity, and you've made me question my understanding of entropy. I've not been formally educated on this subject yet.
Glorc72000
There is an expression than equates the rate of change of temperature to the rate of change of entropy, and many people are mistaught that this relation is the definition of entropy. It is not. Entropy is defined by the equation S = kLog(w), where entropy is S, Boltzmann's constant is k, Log() is the logarithm function, and w is the ratio of the number of ways to combine components of a system to give a particular state to the total number of ways to combine components. For w, imagine a sand castle. Let P be the number of ways to combine sand grains to get a sand castle, and let Q be the number of ALL the ways to combine those same sand grains. Then w = P/Q.
+Existenceisillusion +Glorc72000 The definition you've given would be the definition of the entropy change associated with the sandcastle being formed (ignoring the rest of the system). You can see this by setting the entropy of the sandcastle as S1=klnP and the entropy of the same number of sand grains being spread out as S2=klnQ. Then the entropy change dS = S1-S2 = klnP - klnQ = k(lnP - lnQ) = kln(P/Q)
And since you seem to be insistent on only allowing 'experts' in the field to comment on the physics, I've got a Master's degree in Mathematical Physics.
More fundamentally though, you're coming across very aggressively to a selection of 60S commenters who aren't well educated in Physics who simply want to learn. That is why these videos get created, that is why these videos get views. I think your attitude towards outsiders to the field should be more accepting and more nurturing, given that the point of these educational channels is the make science more accessible to the public. Attacking those who ask questions isn't helping.
Addendum to my reply from before, coming back to read again.
>
Existenceisillusion
10 months ago
elchippe
"...entropy will be at its maximum..."
Actually, what you describe would be entropy at it's minimum. There is exactly one way to arrange all the atoms in the universe such that all atoms are equidistant.
If in this arrangement, you have N atoms arranged all equidistant to each other, then there is N! ways to arrange them. You can interchange any two atoms and still get a valid microstate. This is a MAXIMUM of entropy.
>
Existenceisillusion
7 months ago
Subduralempyema
So you (clearly not a physicist) are telling a physicist that you know more about physics than any physicist? Your reply shows your complete lack of understanding of my previous comment or the principles and concepts on which it was founded.
Sort it out mate. You're clearly not a physicist..
Minun Piina < Hi there, I'm not a physicist. Black holes are (apparently) the most entropic objects in existence, being surpassed only by the heat death. I'm a bit confused by this, why are black holes entropic? Are there even particles to rearrange? Very limited number of shapes for the system to assume as well.
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.
+Kyle Baldwin Well, I assume when you apply this force, which is essentially taking entropy out of the polymers, this entropy is just being shifted somewhere, like heat from whatever process was used to exert the force increasing the entropy of the air around it. So, in this case, the energy didn't go into the polymer, but it was used in the entire system to shift the entropy from one part of it to another.
+Ardy F I agree 'Exactly' True.. 2nd Law is just a statement of probabilities.. So as to the rest of the complications we can apply 'conditional' probability and test for the effect of 2nd Law on part of a system 'given' all the other stuff.. So throwing 20 dice to get 20x6 = low entropy compared to all other possible 'microstates' of those dice.. Its valid because its conditional probability ie Pr(20x6|molecular structure of dice, table, person etc etc..) = 1/6^20..
Unfortunate Phil in trying to say entropy is not disorder.. on the basis of crystal structure resulting from loss of heat to lower temp surroundings.. So natural process producing 'order'.. Only establishes that the reduction in entropy of the subsystem (atoms forming the crystal structure) IS an increase of ORDER while heat to surroundings satisfies 2nd Law for greater increase in DISORDER of surroundings. The fact the process is driven by atomic bond angles is irrelevant to the fact that entropy is a measure of disorder.
Francois Lacombe entropy is a term used to describe the relationship between the regularity we see in the world and how basic interactions and the flow of energy creates it.
I like this definition. It's the way I think of it as well. I think the professor here is jumping around all over the place, and only confuses people.
@Francois Lacombe No, Entropy is exactly NOT a process, it is a function of state. Heat and work are dependend on the path (process), entropy describes the final state, regardless of the path taken.
"AAAAAAAAAAH" - Me after trying to understand this video
I'm betting that someone is going to turn this into a religious discussion.
@Thomso0809
all people need to go.
@scotty
Then why don't you start?
@Thomso0809
I started when I was born, same as you.
@scotty
Touché
@seigeengine "Except for the part where they have to suffer and die."
So, here's a hypothetical (and I imagine that after five years you've refined your thinking, but let's see): If you could have killed all religious types, but they would die painlessly, and not even know it was about to happen before it did, and just instantaneously they get vaporized by a special death ray... That's not genocide?
By the way, if we're going to wish for religious people to die, and I certainly don't, but if that's going on, why not start with the most insufferable, intolerant, self-righteous, judgemental, violent religious zealots in the history of human kind? You know who I'm talking about....
I love this channel. All the speakers are brilliant and the topics too. Thanks for making such great videos!!!
HUNAB KU - TRANCENDENTAL INFINITY I couldn’t agree more
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.
@Sideeq Mohammad "Entropy is a measure of the number of microscopic configurations Ω that correspond to a thermodynamic system in a state specified by certain macroscopic variables." https://en.wikipedia.org/wiki/Entropy
@KWG How does that work if we have an infinite number cards? With an infinite amount of cards every combo could be ordered but it would be beyond our scope of perception would it not?
@William Brandon Davis it does not make any sense. I can't have infinite number of cards. In physics infinite is undefined
It was explained to me once that order is an integral aspect of the universe, in the sense that a human being is a higher state of order than a single bacteria cell, hence why they evolved first, complex order building on lower states of order, all requiring energy input from the sun ultimately, or the biosphere would fall into high entropy through extinction.
A thousand times yes.
People seem to forget that many qualities that we assign to the real world (material world without consciousness bullsh) are just only our human way of thinking/perceiving
About which the real world doesn't give a single infinitesimal damn
'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. :)
And there's a little extra bit: http://youtu.be/maWvwuYR4VA
enim lupin purnum pravus intus
@GagoDrago123 yeah, that's why I suggested it's not worth asking :)
@mazdaplz you can't ever achieve absolutely zero motion, unfortunately, because of quantum. From wikipedia "zero point energy" article: "The uncertainty principle requires every physical system to have a zero-point energy... This results in motion even at absolute zero."
On the other hand - I believe particles which have no mass (photons) move at the speed of light and don't experience time or distance. So I think you could say those particles cross their entire trajectory as if it was contracted to a single instant and point.
Technically correct but completely misleading, and leading you to the wrong conclusion. Molecular speeds in terms of temperature are never anywhere close to relativistic in the human experience. Furthermore approaching absolute zero would be on the stopped end of the scale where the relativistic effect is zero. Hence, going to absolute zero is the limiting case where there is absolutely no time dilation.
+mazdaplz look up plasma
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.
TestMeatDollSteak I find it rather weird , as a 'creationalist' , that this entropy violates my beliefs . I guess I'm just the odd man out. Oh well.
None of you have apparently set in my church . otherwise you might find our beliefs rather interesting , kinda how we come here to gleen knowledge . but I guess open mindedness and respect doesn't truelly flow both ways .
Exactly... my "honors" Physics teacher tried the Entropy argument on us and all I could do was just stare outside at the sunshine.
These replies = people agreeing with the original comment + creationists saying they see no problem with this video, entropy, evolution, etc. As if the type of creationists TestMeatDollSteak was referring to would ever be in the comment section of this video in the first place.
TestMeatDollSteak
Yes, that will make you look way more smarter....
continue to fight entropy every day gentlemen! i'm 100% behind you!
3:01 exactly how i self-taught myself literally, glad i thought of that😱
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.
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.
this guy loves what he does. always energetic
7:22 "W" is now called "Wehhhs."
I'm not sure that was a better explanation.
mr moriarty really got old in the last 6 years. (but he aged well, so no offense)
+karottenkoenig That's Professor Moriarty for you.
+karottenkoenig
Either he was dyeing his hair before and no longer does, or being Sherlock Holmes's main adversary is really tiring. Maybe both.
+Scott Sakurai Or, it could be Heavy Metal poisoning.
I love this guy- he's so enthusiastic. But I just don't get what he is in about here at all!
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?
little observation, entropy would increase in a ever expanding universe thus giving rise to more order yes? or am i missing something..
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 entropy is..............
+Matthew Smith The amount of energy in a system unavailable to do work
+Katie Bennie This or just the amount of possibilities the particles of a system can be arranged. The best example I heard was with a glass of beer:
When beer is fresh from the tap, it has it's whitecap. Now a whitecap seems more disordered than the beer fluid because the fluid is nice, clear and smooth while the cap is a mess of bubbles. But if entropy always increases, why do I need to put energy into the system of beer (blowing into it for instance) to create new bubbles but when I just leave it alone, the cap vanishes. Because actually in the fluid the entropy is higher than in the cap, because the molecules in the cap are limited to the walls of small bubbles which gives the fluid particles less ways to be arranged than in the open fluid. When the cap vanishes over time, the entropy of the beer increases as the beer molecules sink into the open fluid and are free to float and arrange with the other molecules in the glass.
+bxyify This.
+bxyify
I'm saving this! Perfect example. I know beer.
The number of ways that particles can be positioned
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 love how Phil just gets up and struts around in his excitement xD Brady's camera is just all over the room
The cange from amporphed to crystaline in a structure releases heat. Heat has high entropy, so when a system becomes ordered, entropy in universe increases.
7 minutes into the video, you ask "What is Entropy?" and then proceed to introduce concepts which require considerable explanation in their own right. You have created so much confusion on an already complex topic.
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.
@***** Not insufficient for a detailed and comprehensive understanding, insufficient to learn anything new at all. Which was kind of disappointing.
* WOOOSSSHHHHH *
The sound of pretty much all of that going over my head
I love Professor Moriarty's energy when he does the videos!!
Yes! Finally a video saying entropy is not disorder
This video made me cry. I have finally understood entropy. Thank you, professor
I love the interaction with the prof and brady.
May you two never reach entropy!
Love this guy! He's just incredibly passionate !!
Explanation isn't very satisfying.
Explanations in quantum mechanics and thermodynamics aren't always satisfying
I've learned more about what entropy is on YouTube than doing a BS and MS in Mechanical Engineering.
4:40 - Figure 1(a): Simulation of a bag of Skittles traveling through hyperspace
Love this guy! Great respect for his passion for science and explanation.
Moriarty is back!! Love it!!
Amazing subject, amazing video!
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 : very interesting !
Damn I guess I can't use entropy for the reason why my cable collection is always disorganized anymore. LOL
tmjcbs - 2015-06-18
Confusion about entropy always increases
Finn - 2017-06-04
perfect
well done
oldcowbb - 2017-06-16
this should be add into the laws of thermodynamic
Miguel Picanço - 2017-11-14
Well it decreases when you add intelligence.
Oskars Arājs - 2019-04-17
The 4th law of thermodynamics
Jesus McBeth - 2019-12-25
Fkin straight, or rather, that is to say, the the form which contains most entropy