Entropy and the Arrow of Time
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- Опубліковано 19 тра 2024
- What is entropy? In what fields is it useful? And how does it explain the direction in which transformations occur? All these answers in 12 minutes!
0:00 - Introduction
1:30 - Entropy in physics
4:31 - Entropy in other fields
6:25 - The arrow of Time
10:47 - Conclusion
This video is narrated by Octave Masson.
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Alessandro Roussel,
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To learn more :
en.wikipedia.org/wiki/Entropy
en.wikipedia.org/wiki/Arrow_o...
physicoeurin.wordpress.com/ - Наука та технологія
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I totally agree as a fellow Man City fan
@RAYfighter Hi, I watch PBS Space Time and Arvin Ash too, they are good and I learn much things from them, but ScienceClic makes things look so easy just with simple sentences and without unnecessary or too deep things, of course this is my opinion and nobody should be engaged with it.
@RAYfighter I guess we watch the same stuff. Remember to change the channel every now and then, when I fall asleep.
Next, he must tell us why the entropy of the biosphere is continually decreasing, even as the biosphere gets larger as we send out our probes.
Nobody ever mentions dissipative systems.
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Statistical mechanics are fascinating because they require almost no assumptions about the real world, but are able to describe many phenomenons
Agree 100% I do believe the very nature of our universe to be probablistic. QFT is ...
@@lucasbarreira2957 Well, what about Bohmian mechanics?
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I watch other science channels and yours is the one that makes me understand the others and learn, you make it really easy, huge thanks
This is what I’ve been saying. I watched one video on black holes and it was like unlocking a door. I spent the next week figuring out everything I could about special and general relativity, Lorentz transformations, time dilation, all that stuff. I’m not claiming that it’s made me an expert of any of these things, but I can at least say it’s helped make the universe feel a lot less sad and mysterious.
Facts
Exactly
Truly the best. And there is amazing content out there by pbs spacetime and Sean Carrol. But the succinct explanations and visuals make this channel the best. Aren't these same traits what made Feynman such a legend? At the least 3brown1blue level.
It does not explain the arrow of time. Memory only works in the direction of increasing entropy. Its a bit of a tautology.
Your ability to break down complicated subjects so they are easy to understand is remarkable! Your teaching abilities are on par with Richard Feynman himself! Thank you so much and keep up the great work!
I saw the lecture by Sean Carroll on wondrium and that was mind-blowing, but this work of imagination is next level.
Check out his book, The Big Picture
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Already know this is gonna be a good one.
When isn't it?
Channels like this are rare. He understands the material so well and can make great animation to convey it
Honestly this channel is sick. Prolly one the best science channels on UA-cam. I seriously wouldn't have picked A level physics if it wasn't for this.
This channel seems perfectly healthy.
Thank you for another amazing video. Every single video I watch is another "ohhhhhh now I get it" moment, even when I go in thinking I have a grasp of the concept!
This is incredibly good explanation. Entropy was so strange concept to grasp.This style of education will speed up human evolution. We are so lucky to have this easy access to knowledge.
That's right.
I'm less than a minute in and already I can tell this is the best video explaining entropy on UA-cam...
🙏
It really is. I’ve seen a lot of them too.
This or veritasiums video
Your channel has sparked a newfound curiousity for science, I love it !
Now rather than Internet drama, I often get recommendations about the unusual science concepts I never heard before and I'm glad that for once im not consuming junk content
The best explanation of the concept of Entropy on this platform. Thank you Science click English for making me thinking.
You explain concepts that I've heard about in ways that I can finally understand! Thank you!
This is one of my favorite channels you explain things in a very clear manner
I found your channel on a whim, and I haven't been able to stop watching your videos. Truly an incredible experience that even I can understand. Having no real science background, your channel has awakened something within me. Your videos have completely immersed me in the quantum realm, thanks!
The most amazing channel by far, as an undergrad in Physics, I can clearly see that.
I have studied entropy many times in uni and this one is the best I've seen. Thank you so much!
The best way to describe entropy is that the universe is slowly but surely grinding down and erasing all traces of us humans ever having existed
I always thought about this but never knew how to explain it. This video described it perfectly
I'm only at 7:43, but I want to pause to say I really appreciate your relation of entropy to physical experience, when you say that "physical systems tend to homogenize", instead of falling back on a circular argument like "time just passes".
So many shows tend to link "entropy" and "time" in a philosophical or cultural way, but your script reminds us of the importance that "the physical intuition" or sensation or experience of a balloon, or boiling water or melting ice is at the core of discussions about entropy. You make this perspective so clear!
... And of course you have a great sidenote later to clarify that gravitational entropy and other things are still worth thinking about outside of this intuition
Just, wow... Thank you for this. I struggle with these concepts, but that was really well explained.
This might be the best (or at least most intuitive) explanation of entropy. Literally all other UA-cam channels just say that entropy is a measure of disorder without explaining how to measure disorder. I mean, there is no disorder-o-meter. But here the "measure of disorder" was explained as the probability of a family of similar arrangements. Great video :)
It seems as though this explanation presupposes some meaningful notion of familiarity and disfamiliarity on the level of emergent objects (like apples). We can only notice that some arrangements of fundamental particles are arranged 'apple-wise' if the emergent property of 'being an apple' is already a distinguished state (i.e. a 'non-random' state). But seemingly, in asking about the nature of entropy we're really wanting to ask about the nature of all things in our universe, not just those for which there is a predefined meaning to us. So our explanation requires more explaining.
Carlo Rovelli gave an interesting talk (on YT) to the Royal Institute on 'The Physics and Philosophy of Time', where he pointed out that if we had an arrangement of blue and red balls in a box, and separated them by colour (blue on the left, red on the right, say), the box would seem to have low-entropy. But if we became sensitive to minute variations in size, the box of balls would in fact 'all of a sudden' look extremely homogenous (given we only sorted by colour, and not by size; they are 'sorted' with respect to colour, but 'unsorted' with respect to size). It seems to me as though the idea of entropy requires an additional point of reference to be meaningful. I am yet to have this fully click for me (though this channel surely explained more than most others!).
@@HighDensityAwesome That is certainly an interesting detail I haven't yet thought about. The thing is we have multiple rigorous definitions of entropy, which are independent of our perception or whether we give names to some groups of arrangements and not to others. You can blindly apply those definitions without having to know why they are defined the way they are. The problem is intuitively explaining what those definitions mean.
And when using the probability of groups of arrangements as the intuition of what entropy is, it is certainly easier to imagine an apple being a less likely arrangement of particles than a homogeneous cloud of particles. But we don't have to use an apple for this comparison. We could instead talk about abstract density distributions of the cloud of particles. Density distributions with spikes or with two or more regions of different densities are intuitively less likely than a constant density distribution, because the former always evolves into the latter. Now we have an intuitive (to me) picture of entropy that is independent of our perception and whether we give a name to certain arrangements.
We can even go one step further and declare two distributions "similar", if their difference is sufficiently small. How small? Well, that will depend on what kinds of distributions we want to distinguish (e.g. apples and homogeneous clouds).
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@@mark2359 ?
This a beautifully done video on entropy. I've always been fascinated by this subject.
Part of the magic of this channel has got to be the perfectly timed music ... it sucks me right in the mystery and gives me that near Hitchcok-like suspense of wondering what comes next ... makes me feel like I'm at the edge of my seat in amazement and wonderment!
Exactly!!
How on earth this guy continuously keeps amazing us with his amazingly beautiful and easy to comprehend animations
This is the best explanation of entropy I've seen yet, thank you
I love this channel so much. Concepts are explained in such a way that I can actually get a grasp on what's being said. I love it!
Man... this is by far the best explanation of entropy. Thanks
Agreed with most comment. By far this is the best physics channel. I was finally understood Einstein's GR and SR also from this channel. Keep it up!!!
This was brilliant!
The only thing I didn't get was how the expansion of the universe could prevent heat death
it's a classic for this channel to throw in a different topic at the end to keep you curious and aware of how much stuff the simple explanation is leaving out :D
Possibly, if you look up conformal cyclical cosmological (CCC) , By Sir Roger Penrose you'll get an idea.
It's pretty hard to ' bore' a photon.
Happy watching.
May be cause space os also slowing down further we expand, which creates cooler vacuum rather than hot... something like that.... Just a thought
Maybe because if space itself is ever expanding while the total energy of the universe is unchanged that there will be an ever increasing number of possible states, i.e. ever increasing entropy?
@@heavy-gauge I dont think so. The universe will get to an equilibrium state, where nothing exists, All of the matter will disappear overtime and the system will reach its max entropy and the concept of time will disappear.
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You simply don't cease to amaze, the conciseness of your videos is on a whole different league, and your ability to build up ideas in an intuitive way, with minimal and yet full context is pure teaching talent.
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Thank you so much. I'm working on an article for my university, and you helped me a lot!
A minor critique regarding the balloon example (6:39):
Picking a balloon instead of a rigid container (eg an open bottle) makes the whole situation needlessly complicated and ambiguous.
The balloon itself will go from a stretched/inflated to a relaxed/deflated state (and thereby pushing out whatever is inside), no matter how the air molecules are initially distributed within the whole system.
The balloon will ALSO relax due to entropy. If you stretch a rubber band, it will warm up. This is due to the relationship of temperature and entropy, where the temperature must go up if we go to a lower entropic state.
This channel is pure gold
One of the best, maybe the best science channel, at least for GR.
Entropy is a tricky topic and rightfully there is a disclaimer at 8:41: degree of (increasing) structure is many times confused with a degree of lower Entropy and vice versa: higher Entropy less Structure (also not true in general). E.g. two layers of oil and water phase separation (looking more structured) has higher Entropy relativ to an oil-water mix after shaking.
I wish that this is the first of an introductory videos to that fundamental subject.
Dear Octave, Alessandro + your esteemed audience,
First of all, many sincere thanks for your collective efforts!
"What is entropy? In what fields is it useful? And how does it explain the direction in which transformations occur? All these answers in 12 minutes!"
...sounds terrific, but this is definitely not for an average mind...
...Even big scientific research workers' brains had and still have to stumble herewith...
Hence, some kind of a clarification ought to be urgently necessary!
So, captain, AHOY!
A. There is ONLY ONE BASIC, fundamental Energy Conservation and Transformation Law. It is definitely unique and conceptually indivisible delivering two logically joint concepts - these are Energy Conservation - and Energy Transformation. Still, a more-then-100-years-old conceptual failure has brought us to two separate thermodynamic laws - but this has nothing in common with the actual physics. To come back, they have coined two more fake thermodynamic laws, employed the Probability Theory + Mathematical Statistics, and this has helped formulate the Quantum Mechanics, which is thus a basically metaphysical conceptual construction - and, hence, ought to be only restrictedly fruitful.
B. By dividing the basically indivisible law, you are touching Combinatorics, you are touching Probability Theory, you are even stepping back to Thermodynamics for a while, but...
You are NOT answering the poser: WHAT IS ENTROPY, sorry!
1. In the formula S = kB * ln(Ω) you do imply, Ω means not a "Huge Number of Microstates", not "Probability", which numerically ranges between [0,1], not even "Wavefunction", which ought to be a purely metaphysical notion, as it is... In effect, Ω ought to be a simplistic algebraic function of Lord Kelvin's Absolute Temperature. This result has been published 100 years ago in JACS.
2. WHAT-ENTROPY-IS-poser has been answered not by Clausius, not by Boltzmann, etc., but by Goethe, who has introduced Mephistopheles, the philosophical embodiment of ENTROPY.
3. Newton did basically know WHAT ENTROPY IS - A Counteraction.
4. That Counteractions do not grow to infinity with the growing Actions, but MUST reach their MAXIMUM values, is the result by Nicky Carnot, which has been formalized by Clausius...
5. In effect, J. W. Gibbs Free Energy formula:
(ΔG = U + pV - TS, .i.e.,
ΔG = H - TS, where
U is the internal energy (SI unit: joule),
p is pressure (SI unit: pascal),
V is volume (SI unit: m3 = m*m*m),
T is the temperature (SI unit: kelvin),
S is the entropy (SI unit: joule per kelvin),
H is the enthalpy (SI unit: joule))
renders implicit the interplay among ALL the relevant Actions (the Enthalpic term) and ALL the pertinent Counteractions (the Entropic term).
6. The standard approach you are reporting about is OK for the implicit Enthalpy-Entropy picture, employing it, e.g., for studying reaction mechanism details is likewise eating soup with a fork.
The above is about 'Entropy' in Physics, Chemistry, Biology, etc., etc., etc. ...
Entropy in other fields:
Be aware of a powerful trend to build up misnomers in many other fields, for Entropy is the proper term solely for the "Energy Transformation", whatever nature/origin this energy might be of.
The Arrow of Time:
This is not due solely to Entropy, but owing to Eternal Entropy-Enthalpy Compensation.
This is why, the Heat Death you are proclaiming over and over again ought to be just a useless legacy.🧐
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The best voice on the internet by far
You, Sir, just earned yourself a new subscription.
Finally! We had to wait for some while… Thanks again!
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YOu are smashing the old theories in a new visualization, thanks for the effort which help the next generation to perceive big theories in a simple way ... A big bow !
One of my favorite topics. Thanks.
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Amazing video. Clear and easy to follow, at last explained properly 😎
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Me on being an indian ,searched i was not getting any relevant video of indians...then i found this which explained the concept welll and in interpetable accent...
entropy and the egg, essentially our newton's apple.
dude blew my mind in 30 seconds, the egg CAN be put back together because we have more data for what it WAS! all it takes is a simple time swipe backwards with the correct parameters.. the universe is so fundamental when it clicks.
This channel is next level
These guys always produce high quality videos
Every member of the human race needs to see this and work to understand it.
And for what? lol
Some peoples are exploring some subjects, the others are exploring the different ones. It all depends on what peoples expect in life and how they aproach it.
Some peoples love quantum physics and math, some music, art, the others military, craft etc.
U cant be alpha and omega.
U can say "bUt for tEh geNeRaL kNowLedg". Cmon, because someone do not know what is entropy in physics it doesnt rly change a thing.
Every human is different.
What do they need to understand it for?
Watching this legend's videos under a thousand views
This is what gives life meaning
This is the best channel on UA-cam.
Best video on entropy on YT! I’ve been looking, too, to help explain it to my high school son. As always, great work.
Now just stop saying “further” when the correct word for physical distance is “farther” hahaha.
I hadn't watched this video before....then I saw it.....and now I'm MORE useful. I tricked entropy right outta business!
Yo that particle arrangement diagram was swag as hell. Could you consider making art using that style?
I'm not sure that the explanation of the tendency for entropy to increase with time explains the arrow of time. The thought experiment (and discussion that follows) I first heard from Carlo Rovelli: Imagine removing the partition in the middle of a box separating vacuum and a uniform gas; allow the gas to evolve in time and it begins to partially fill out the previously empty space; before equilibrium is reached, say when the gas is "3/4 of the way to uniform" freeze time; if, then, we evolve forward in time, the expansion completes as expected, but, if instead we run time backwards, **the same thing happens**, the gas still evolves to a high entropy state, filling the container uniformly! So why do we associate an arrow of time with an increase with entropy? Because entropy was lower in the past. The gas was pumped into half the container using low entropy electricity generated by low entropy fuels that came from low entropy solar radiation and on and on back to the big bang. Why was entropy lower in the past? That is the mystery. Hopefully someone else remembers this argument better and can provide some links!
How would the reversal make entropy increase?
It was low entropy before and it became higher. Reversing that makes entropy lower
@@biblebot3947 "Before" and "became" are "time words" ... that is, they are only defined if you *already assume* an arrow of time. Otherwise, how would you know which direction was "before" and which direction was "became"?
@@rfyl that was done in the thought experiment when the arrow of time was reversed and the entropy supposedly increased
@@biblebot3947 In the thought experiment, he's not saying that entropy "supposedly increased" when the arrow of time was reversed. Rather, he's saying that the *argument* for why entropy increases towards the future should logically equally well apply if you look at the picture "backwards", and entropy therefore *should* also increase towards the past ... and yet it doesn't.
The Huw Price article (book, actually) which I linked to elsewhere says that way back when Boltzmann first introduced these various concepts, he (Boltzmann) also realized that his arguments *should* apply equally well when looked at in reverse -- entropy logically *should* increase towards the past, as well as towards the future -- and the real mystery is why it only increases in one direction. (And that the mystery is also why we happen to live in such a relatively low-entropy time.) That book explains Boltzmann's reasoning, Boltzmann's solution to the problem (which Price says was ultimately incorrect, but much closer to correct than anyone's solution until recently). The book does so far more clearly than I can do ... and in far more detail than I'm willing to attempt to give. ;^) So I strongly recommend it.
Basically, since low entropy is less likely than high entropy, the states *surrounding* a low entropy state *ought* to be higher entropy -- surrounding on *both* sides (I'll call them "left" and "right", rather than "past" and "future", just to avoid using words which already presuppose a direction of time).
I am still a low entropy system relieved to say at least for this Planck space and moment.Thanks for your remarkably simple methods.Cogito ergo sum!
This is epic! You should try doing a video on the quantum hall effect :)
Brilliant science explanation plus ASMR.
Thank you! I'd learned and knew entropy is positive in each system since every non-equilibrium sysm goes toward increasing disorder, but you simply introduced homogeneity, which explains this concept more sensible.
I can't believe you're only 23. It's one thing to have an educational background as impressive as yours, as well as talent with music and art. But the fact that you're able to write and produce things in such an explainable manner at such a young age is just prodigious. I thought originally that this must have been a team of people. I was shocked when I clicked your bio link.
I heard it explained that this is why wired earbuds tend to get inextricably tangled in a pocket: there’s only one way for them to be untangled and nearly an infinite number of ways for them to be tangled. The likelihood of it being untangled is very low compared to any other configuration.
Word.
great; more on entropy and the arrow of time please
I just finished your videos explaining general and special relativity and I have to say I was caught off guard by your natural talent as a teacher. Your videos are very impressive on their own, and you're ability to dive into such nuanced theories for 10-15 min at a time, without going on tangents or losing your focus, is what really makes you such an effective teacher in my mind.
I genuinely understood 100% of all the things you said, which is not something I get out of any other videos from educational UA-camrs like Vsauce, PBS Space Tme or Veritasium, even though they're titans with millions of subs and plenty of money and time. Other educational videos almost always start with a single topic, but become unintentionally superfluous as unnecessary tangential information is pilled on. You are laser focused, you'll give several extremely relevant, yet simple experiments that offer unique visual representations in order to shed more light on a single topic.
You did this while covering general relativity when you visualized space-time in 3d while also using a warping grid to represent the passage of time as an apple falls towards earth. Considering your other videos and explanations, it's easy to see how creative, concise and coherent you are as a creator/educator overall. Serious props man, you're fantastic
ScienceClic! I'm your new fan! I love watching Science videos, but trust me, you're the first ever Science channel I've subscribed to. Your explanations are spot on! To a point that is just right for me. Can you do dark matter/energy next time? Videos from other channels just don't suffice for me for some reason, and I hope that you'd consider!
Great as always! Thanks!!
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Honestly the best physics channel for understanding any Complex subjects. Would be really cool to see you doing a video on tensors
It’s cool how you mention something that can give us goosebumps at the end, then just end the video
fascinating video and really well deliverd.
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I was just REALLY thinking about this.
I love this. Thank you!!! 🥰
Been waiting for a video like this. Entropy is best understood is a heat tax and the reason why time only travels forward. To reverse time is to reverse physical processes, and a perfectly reversible process with no energy loss is not possible because a perfect insulator would imply it aborbs molecular collisions without absorbing energy.
This is an amazing explanation
Incredible good approach to explain this complex term entropy ...Ludwig Boltzmann would be delighted...
This is the first time entropy has clicked for me. Thank you.
Love these, a lot. Keep em comin baby!
Nice explanation... Thanks you.
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What an explanation!!🤩
The entropy of this channel never increases.
I come here for good clear thoughts. I'm never disappointed.
this brings so many more questions
if only we understood the universe at its smallest scale...
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As always, great video!
Thanks!
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It makes you wonder about boiling water at different altitudes; where air at high altitudes has a higher entropy which means reduced air pressure.
This allows water to boil at lower temperatures than sea level because there is less dense air molicules holding down and preventing the entropy increasing by gravity.
Its also why steam or heat rises rather than falls like dry ice vapour.
at higher altitudes there's less pressure, but less pressure means it's colder and so entropy is lower