Oh I finally understood it! Thanks! I was searching many videos to find out how the entropy can increase when two bodies exchange heat, and your video is the only one I could understand!
You did an excellent job at explaining this concept. I learnt more from listening to you for 30 minutes then i did attending three 1 hour lectures at uni. If i had you as my physics teacher in high school i probably wouldn't hate the subject so much. Well done!
At 6:15 I was beginning to wonder if the presentation was intended to illustrate pedagogical entropy, but wasn't going to waste my time further to find out.
This was very helpful!! Learnt more in a day that I did this entire semester in Thermodynamics!! :D :D I'm going to ace mid terms b/c of you! Thank You!!!
Sure! Fun question. Rust and the decay of mountains and flowers wilting can be seen in entropy terms 'cuz it's more ORDERED to have all the iron or mountain (or water in the flower) in one place, rather than spread out. Thus, lower entropy when initially organized.
thank you....this video really helps :) ...but can't you make more videos about thermodynamics that is needed as an introduction to statistical mechanics!
question; when the hot and cold blocks are placed next to each other, as they exchange heat to reach equilibrium, their temperatures change, right? So how can we say that for each block, ΔS = Q/T ? This equation, as I understand it, is only valid if the heat source acts as a heat reservoir (ie stays at constant temperature during the heating process). If the heat blocks change temperature, then don't we have to find some equivalent reversible path ΔS= C ∫dT/T between the initial and final temps
S= Q/T, if u are adding heat then temperature should also rise,then how can we say that entropy increases on adding heat..as the ratio (Q/T) can remain same...
Sir, if the heat is entering the cold material then it's probably taking some time to do that in that time the temperature of the cold body also increase so how could you do the math of entropy with only a single temperature
I have a problem with the last point of getting to 0K. You are assuming that temperature is non quantifiable. Perhaps at some point you'd reach the lowest possible positive temperature. Then you'd only have 1 "unit" of heat left to remove. You cannot divide it any further. What happens?
okay I think I got this down. Well somewhat. However, im confused on that you use qc/tc and qh/th as seperate equations rather than how you first displayed them (qc/qh=tc/th. why is this? in addition why doesnt it have an equal sign yet the two values you created werent equivalent ? would this mean that the difference between the two quantities would be the change in entropy? excuse my lack of knowledge im a senior in highschool who is just getting into physics.
Entropy of the colder body is lower than the hotter body , but the change in entropy of the colder body increase more than the change in entropy of the hotter body? The change in entropy of the colder body is positive in the equation because the energy is being added to the colder body & The change in entropy of the hotter body is negative in the equation because the hotter body is giving out energy?
8:36 talk to me about this reversible engine... I am curious about this. I was thinking something like a sterling engine that is a reversible process because you can add heat or remove heat and it works the same way? I realize at the end of the day it's still just heat transfer making it work. I was thinking we're screwed because energy cant be created or destroyed... but I can buy that 100% since all that is had to come from somewhere (maybe) energy-wise so maybe thats the remaining energy keeping us above 0-kelvin? lol idk I agree this is likely if the universe just sits around forever then it will just equal out and be blah... I like thinking about ridiculous hypothetical stuff. I have a lot of crazy ideas for alternate energy.
I have LOTS of thermo videos, but just at the introductory level. I hope they will help you understand the concepts and motivate you to continue your study. Have you seen the videos from chapters 15, 16, 17, and 18 playlists? I hope they help.
Humanity.. We are as the letter "X" the great variable capable of nothing and yet everything as well. I believe future generations will surpass the heat death of this universe in its entirety..
hmm personally I dont see heat death being avoidable under any circumstance. id go into an explanation but if you payed attention to the video or looked further into the theory you understand. basically it should be viewed as the universe is expanding at an accelerated rate allowing for particles to disperse into further regions and cool. so unless humans find a way to make the universe finite then I dont see it as a possibility
Entropy of the universe is always positive, and I get that. I do wonder, though, how increasing entropy would be bad if the universe is also undergoing accelerated expansion. If anything, shouldn't we be favoring increasing entropy as a function of time? Perhaps entropy could even be the cause of an expanding universe, as dictated by thermodynamics?
Lovely idea, that. As we wrestle with the idea of accelerated expansion and dark energy, we can no longer even say that energy is conserved. At that point, I begin to get frustrated. You've got reasonable points!
Since it is the same deck of cards with the same amount of cards, so it is just another state of the system, while entropy is the amount of states a system can have, isn't that right? Anyway, this was really entertaining
Ooh, I think you mean I am assuming that heat is non-quantized. That is, I assume I can add or subtract arbitrarily small amounts of energy. Of course, we know that's not true. I have never studied the quantum treatment of thermodynamics, but I presume it'd be pretty interesting, as you suggest!
Read my article "Diode Rectifies Thermal Noise" in Research Gate. Type : "H. Tomasz Grzybowski" in Google, click on "H. Tomasz Grzybowski on Research Gate", then click on "contributions".
Mustafa M The second explanation is easy to misunderstand - it's a statistical measure, so order always has far fewer possibilities than disorder. That's why the increase in entropy of the universe might be even more fundamental than physical laws - it's a mathematical result, independent of the universe's structure entirely. Cool.
isn't entropy more a measure of the number of possible states of a system. In your deck of cards anaology... the odds of the deck being ordered in ANY particular way are equally improbable, it's just that we give meaning to certain configurations and not others. is there a requirement that the constituent parts be indistinguishable, or I'm I pulling that out me arse?
Indeed. If the constituent parts are indistinguishable, then the entropy of a mixed or spread-out state is far higher than the entropy of separated groups or a concentrated lump. What's really interesting is showing why doubling the volume of a container increases the entropy of the gas inside.
In that case, wouldn't it be the result a there being more possible position for the particles to be in. (k ln(2^N) more, isn't?). But aren't the positions of the individual particles just microstates and if P,V, n, T don't change then the entropy would also not change? So if we move particles around, but don't mess with the variables in the equation of state, then S would be the same for the system regardless of whether the particles were clumped together or smeared out? And thanks for the quick response! I'm really interested in this subject, but I'm just relearning it now and your videos are great! Watched a bunch of the nuke physics ones too. Could you recommend a good Thermodynamics text for the serious layman? I'm relearning calc/diff eq in my spare time (for fun, I swear) but it's been 22 years since I learned this stuff so some kinda intermediate level text would be great. First/second year of college level I'm guessing. Anyways, thanks for putting out such great content. It's a fabulous resource. I really wish the web was around when I was in high school. Would have made a huge difference for me.
If V increases, what else does the ideal gas predict? What sort of expansion is it as the gas fills the newly available space? If you draw a speed distribution for two different temperatures, you can reason through the way entropy depends on temperature. I find that very cool. An Introduction to Thermal Physics by Schroeder was my undergrad text. It's a little on the fun side, and the author went to my high school!
Well, since the gas is doing no work, it's simply moving into the new space, it's a free expansion. So the V gets bigger but the avg kinetic energy of the particles doesn't change, so there's no change in T. Assuming here that the system is completely isolated so there's no heat flowing in or out. So speed distribution... for lower T the curve is shifted to the left and the peak of the curve (that's the most probably speed, right?) will be higher for a given number of particles than for the same gas at a higher temperature. The higher temp curve will be "shorter" and wider. This means that there is a larger range of possible kinetic energies available to the gas particles and thus S must be greater. Is that about the measure of it? I'll see if I can find that text. Thank you for the suggestion!
I'm not so sure about that explanation of the 3rd law. Your proof that we can't reach Absolute Zero sounds like Zeno's paradox to me. Replace 0 Kelvin with 0 Celsius and you could use the same "proof" and it would be demonstrably false.
Zach Fetterman Celsius isn't an absolute temperature so that wouldn't make any sense. His way of explaining it is to better understand. In a more complex matter, the atoms of whatever you are "supercooling" to achieve 0K will always have some form of vibration thus preventing 0K.
John Doe Its not better if its wrong. That's a false proof. There is a valid reason as to why we cannot reach 0K, however the reason he says is not it. Again, its called Zeno's paradox. Take a minute and look it up. Specifically, the dichotomy problem. Its quite dangerous, I think to teach people that as long as the conclusion is sound, that any steps to get there is a valid explanation, which is what you are suggesting. I believe Zeno's paradox was refuted by Aristotle more than 2,300 years ago. He drew a line on the ground and walked across it. Its 2017...is it really productive to resurrect these failed arguments?
Zach Fetterman you sound more based on a philosophical interpretation than scientific. It is impossible to get to zero kelvin because there is always entropy within the system (heat energy, vibrations, etc) as I just stated above. The laws of thermodynamics are statements built upon statements which make it pretty hard to explain to someone who isn't built for science because it's so abstract, hence why his simple statement that we can't achieve zero kelvin is the third law in a nutshell. Read up on some thermodynamics, might give a clearer explanation than this video.
John Doe I don't think you get it. I agree with you about the science. What you said is a perfect explanation. If the proof given in this video was what you said with a little more detail, that would be fantastic. I am arguing that we SHOULD have been provided with the scientific explanation. Instead, we got a false mathematical proof that is based on a philosophical argument called Zeno's paradox. What he says in this video does not suffice as the reason we cannot achieve 0K. Again, just because a fact is true, doesn't mean all explanations as to why it's true are valid. It is the author of the video who is trying to give a phyosophical proof with mathematical support instead of the actual scientific one. I don't get why you can't admit that this proof by induction is incorrect.
Zack you're right, as his explanation was somewhat false however he could not go into detail so he had to make a brief explanation. But the fact of not reaching absolute zero is correct as you stated.
According to the 2nd law of thermodynamics, " The total amount of Energy in the universe ganna decrease till it reach zero and this depend on the increase of entropy principle " But in fact we Muslims know this fact since the delegation of prophet Mohammed PBUH, God said in Holly Quran (يوم نطوي السماء كطي السجل للكتب كما بدأنا أول خلق نعيده وعدا علينا إنا كنا فاعلين)
PLEASE RESHOOT THIS CLIP. You are adressing interesting issues, but you are all over the place and just ... it's a bad clip. Very bad. I don't want to downvote it, which is what it deserves, because I want to encourage science clips on TH-cam. But honestly, this is terrible. :/
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I just cleaned my room. . .shit.
being lazy extends the lifespan of the universe.... (just a thought)
Oh I finally understood it! Thanks! I was searching many videos to find out how the entropy can increase when two bodies exchange heat, and your video is the only one I could understand!
You did an excellent job at explaining this concept. I learnt more from listening to you for 30 minutes then i did attending three 1 hour lectures at uni. If i had you as my physics teacher in high school i probably wouldn't hate the subject so much. Well done!
At 6:15 I was beginning to wonder if the presentation was intended to illustrate pedagogical entropy, but wasn't going to waste my time further to find out.
you're one of the best teachers dude. keep it up!
im finding this whole entropy business extremely fascinating
Yessir
This was very helpful!! Learnt more in a day that I did this entire semester in Thermodynamics!! :D :D I'm going to ace mid terms b/c of you! Thank You!!!
Guy, you're just amazing! Everything was so easy and interesting, thanks!
Pleases tell me about heat death of universe 😔😔
I think you're totally right. I believe we could say ΔS >= Q/T for each block, at least. I glossed over that temperature change entirely!
Thank you! This helped immensely. I loathe teaching thermodynamics...but my attitude is changing now. I'm excited for Entropy
Oh doc I just loved ur way of explaining
OMG THIS WAS AMAZING!!SUBSCRIBED❤
wow...what a fascinating guy
I had a "woah moment" there when you explained the 3rd law of thermal dynamics :D
Chris Sutton physics is all about having the "whoa" moments
I learned a lot watching this, It's a really good crashcourse in thermodynamics. Thanks a lot :)
I have an exam in thermo II today. Yet here I am binge watching all these vids. Hahaha this is good. Pretty much easier to understand.
Sure! Fun question. Rust and the decay of mountains and flowers wilting can be seen in entropy terms 'cuz it's more ORDERED to have all the iron or mountain (or water in the flower) in one place, rather than spread out. Thus, lower entropy when initially organized.
Thank you for reminding me that even the universe is mortal. That all creation will one day die and there is nothing we fan do about it
love your videos your like the deadpool of science
Memento mori. Because everything will inevitably die, even the universe
although i m still confused about entropy , bt i thoroughly enjoyed ur video
+vedant AGGARWAL Entropy is very tricky. Luckily it can be seen in various ways, so keep studying!
Sounds like the main guy in Scorsese's 'After Hours'
thank you....this video really helps :)
...but can't you make more videos about thermodynamics that is needed as an introduction to statistical mechanics!
Can u please tell me What does a reversible process mean?
This reversible word is getting difficult for me to understand...
Faltu ki baat hai
How did they realise that if every c is in one side and and every h is in the other side, there would be a new thermodynamic property?
question; when the hot and cold blocks are placed next to each other, as they exchange heat to reach equilibrium, their temperatures change, right? So how can we say that for each block, ΔS = Q/T ? This equation, as I understand it, is only valid if the heat source acts as a heat reservoir (ie stays at constant temperature during the heating process). If the heat blocks change temperature, then don't we have to find some equivalent reversible path ΔS= C ∫dT/T between the initial and final temps
thermodynamics is fascinating
S= Q/T, if u are adding heat then temperature should also rise,then how can we say that entropy increases on adding heat..as the ratio (Q/T) can remain same...
Sir, if the heat is entering the cold material then it's probably taking some time to do that in that time the temperature of the cold body also increase so how could you do the math of entropy with only a single temperature
I like this
awesome explanation sir, thank you.5'S⭐
I have a problem with the last point of getting to 0K. You are assuming that temperature is non quantifiable. Perhaps at some point you'd reach the lowest possible positive temperature. Then you'd only have 1 "unit" of heat left to remove. You cannot divide it any further. What happens?
Was it really Lord Kelvin who first realized that Qc/Tc=Qh/Th? I thought it was Sadi Carnot who did it in his studies of efficiency of heat engines...
okay I think I got this down. Well somewhat. However, im confused on that you use qc/tc and qh/th as seperate equations rather than how you first displayed them (qc/qh=tc/th. why is this? in addition why doesnt it have an equal sign yet the two values you created werent equivalent ? would this mean that the difference between the two quantities would be the change in entropy? excuse my lack of knowledge im a senior in highschool who is just getting into physics.
Entropy of the colder body is lower than the hotter body , but the change in entropy of the colder body increase more than the change in entropy of the hotter body?
The change in entropy of the colder body is positive in the equation because the energy is being added to the colder body &
The change in entropy of the hotter body is negative in the equation because the hotter body is giving out energy?
8:36 talk to me about this reversible engine... I am curious about this.
I was thinking something like a sterling engine that is a reversible
process because you can add heat or remove heat and it works the same
way? I realize at the end of the day it's still just heat transfer
making it work. I was thinking we're screwed because energy cant be
created or destroyed... but I can buy that 100% since all that is had to
come from somewhere (maybe) energy-wise so maybe thats the remaining
energy keeping us above 0-kelvin? lol idk
I agree this is likely if the universe just sits around forever then it will just equal out and be blah... I like thinking about ridiculous hypothetical stuff. I have a lot of crazy ideas for alternate energy.
Thanks for the honest feedback! Heck, it's got four downvotes already. This one is on my hit list.
You know entropy disproves the big bang theory
Your saying order is unlikely , then why crystal forms so orderly organised structure ?
Basically to know about entropy you hv to go back to Big Bang when the universe began, hence entropy was organised then
how do know if
that random is not order and order is disorder and it can be reversed
Yeah but heat exchange is not reversible how come you get to use the formula for the reversible heat when deriving entropy change?
I have LOTS of thermo videos, but just at the introductory level. I hope they will help you understand the concepts and motivate you to continue your study. Have you seen the videos from chapters 15, 16, 17, and 18 playlists? I hope they help.
Are you atiest?
Ending sentence was interesting..
Humanity.. We are as the letter "X" the great variable capable of nothing and yet everything as well. I believe future generations will surpass the heat death of this universe in its entirety..
hmm personally I dont see heat death being avoidable under any circumstance. id go into an explanation but if you payed attention to the video or looked further into the theory you understand. basically it should be viewed as the universe is expanding at an accelerated rate allowing for particles to disperse into further regions and cool. so unless humans find a way to make the universe finite then I dont see it as a possibility
we cant escape time fam
We can locally decrease entropy; however, and prevent the heat death of the universe.
heat death is billions of years away while our species might not last millions of years into the future
Entropy of the universe is always positive, and I get that. I do wonder, though, how increasing entropy would be bad if the universe is also undergoing accelerated expansion. If anything, shouldn't we be favoring increasing entropy as a function of time? Perhaps entropy could even be the cause of an expanding universe, as dictated by thermodynamics?
Lovely idea, that. As we wrestle with the idea of accelerated expansion and dark energy, we can no longer even say that energy is conserved. At that point, I begin to get frustrated. You've got reasonable points!
This is depressing.
Bomb digs
Since it is the same deck of cards with the same amount of cards, so it is just another state of the system, while entropy is the amount of states a system can have, isn't that right? Anyway, this was really entertaining
Ooh, I think you mean I am assuming that heat is non-quantized. That is, I assume I can add or subtract arbitrarily small amounts of energy. Of course, we know that's not true. I have never studied the quantum treatment of thermodynamics, but I presume it'd be pretty interesting, as you suggest!
#3:01 order is unlikely no need to clean the room
Am i the only one who actually cleaned my room?
Read my article "Diode Rectifies Thermal Noise" in Research Gate. Type : "H. Tomasz Grzybowski" in Google, click on "H. Tomasz Grzybowski on Research Gate", then click on "contributions".
After 11:55 : "LIFE HAS VALUE". Haha, you are a funny guy. Is this physics or philosophy?
So entropy is a measure of how dispersed energy is in any system.....
Mustafa M Oooh - how smoothly it is distributed? I love it.
Doc Schuster This is how my Chemistry teacher explained it. I think he also said it is the number of states a system can have.
Mustafa M The second explanation is easy to misunderstand - it's a statistical measure, so order always has far fewer possibilities than disorder. That's why the increase in entropy of the universe might be even more fundamental than physical laws - it's a mathematical result, independent of the universe's structure entirely. Cool.
So our universe will die in the future!
or neg poss same same
your adding chemicals, veriable counter parts.. possiblities endless.. simply neg poss..
But 0k looks similar to ok.
That's why he calls it the "it's not going to be OK" law.
isn't entropy more a measure of the number of possible states of a system. In your deck of cards anaology... the odds of the deck being ordered in ANY particular way are equally improbable, it's just that we give meaning to certain configurations and not others. is there a requirement that the constituent parts be indistinguishable, or I'm I pulling that out me arse?
Indeed. If the constituent parts are indistinguishable, then the entropy of a mixed or spread-out state is far higher than the entropy of separated groups or a concentrated lump. What's really interesting is showing why doubling the volume of a container increases the entropy of the gas inside.
In that case, wouldn't it be the result a there being more possible position for the particles to be in. (k ln(2^N) more, isn't?). But aren't the positions of the individual particles just microstates and if P,V, n, T don't change then the entropy would also not change? So if we move particles around, but don't mess with the variables in the equation of state, then S would be the same for the system regardless of whether the particles were clumped together or smeared out?
And thanks for the quick response! I'm really interested in this subject, but I'm just relearning it now and your videos are great! Watched a bunch of the nuke physics ones too.
Could you recommend a good Thermodynamics text for the serious layman? I'm relearning calc/diff eq in my spare time (for fun, I swear) but it's been 22 years since I learned this stuff so some kinda intermediate level text would be great. First/second year of college level I'm guessing.
Anyways, thanks for putting out such great content. It's a fabulous resource. I really wish the web was around when I was in high school. Would have made a huge difference for me.
If V increases, what else does the ideal gas predict? What sort of expansion is it as the gas fills the newly available space?
If you draw a speed distribution for two different temperatures, you can reason through the way entropy depends on temperature. I find that very cool.
An Introduction to Thermal Physics by Schroeder was my undergrad text. It's a little on the fun side, and the author went to my high school!
Well, since the gas is doing no work, it's simply moving into the new space, it's a free expansion. So the V gets bigger but the avg kinetic energy of the particles doesn't change, so there's no change in T. Assuming here that the system is completely isolated so there's no heat flowing in or out.
So speed distribution... for lower T the curve is shifted to the left and the peak of the curve (that's the most probably speed, right?) will be higher for a given number of particles than for the same gas at a higher temperature. The higher temp curve will be "shorter" and wider. This means that there is a larger range of possible kinetic energies available to the gas particles and thus S must be greater. Is that about the measure of it?
I'll see if I can find that text. Thank you for the suggestion!
If you're trying to understand this for an exam or presentation, I just want you to know that everything will be OK....not!! Siiiiiiiiiiiiike
it cant be, because, its poss neg... ending in one time
has anyone ever told you you sound like ryan reynolds
I'm not so sure about that explanation of the 3rd law. Your proof that we can't reach Absolute Zero sounds like Zeno's paradox to me. Replace 0 Kelvin with 0 Celsius and you could use the same "proof" and it would be demonstrably false.
Zach Fetterman Celsius isn't an absolute temperature so that wouldn't make any sense. His way of explaining it is to better understand. In a more complex matter, the atoms of whatever you are "supercooling" to achieve 0K will always have some form of vibration thus preventing 0K.
John Doe Its not better if its wrong. That's a false proof. There is a valid reason as to why we cannot reach 0K, however the reason he says is not it. Again, its called Zeno's paradox. Take a minute and look it up. Specifically, the dichotomy problem. Its quite dangerous, I think to teach people that as long as the conclusion is sound, that any steps to get there is a valid explanation, which is what you are suggesting. I believe Zeno's paradox was refuted by Aristotle more than 2,300 years ago. He drew a line on the ground and walked across it. Its 2017...is it really productive to resurrect these failed arguments?
Zach Fetterman you sound more based on a philosophical interpretation than scientific. It is impossible to get to zero kelvin because there is always entropy within the system (heat energy, vibrations, etc) as I just stated above. The laws of thermodynamics are statements built upon statements which make it pretty hard to explain to someone who isn't built for science because it's so abstract, hence why his simple statement that we can't achieve zero kelvin is the third law in a nutshell. Read up on some thermodynamics, might give a clearer explanation than this video.
John Doe I don't think you get it. I agree with you about the science. What you said is a perfect explanation. If the proof given in this video was what you said with a little more detail, that would be fantastic. I am arguing that we SHOULD have been provided with the scientific explanation. Instead, we got a false mathematical proof that is based on a philosophical argument called Zeno's paradox. What he says in this video does not suffice as the reason we cannot achieve 0K. Again, just because a fact is true, doesn't mean all explanations as to why it's true are valid. It is the author of the video who is trying to give a phyosophical proof with mathematical support instead of the actual scientific one. I don't get why you can't admit that this proof by induction is incorrect.
Zack you're right, as his explanation was somewhat false however he could not go into detail so he had to make a brief explanation. But the fact of not reaching absolute zero is correct as you stated.
Who is here because of vsauce's newest vid?
You've been drinking again.
Will you please have my babies?
According to the 2nd law of thermodynamics, " The total amount of Energy in the universe ganna decrease till it reach zero and this depend on the increase of entropy principle "
But in fact we Muslims know this fact since the delegation of prophet Mohammed PBUH, God said in Holly Quran (يوم نطوي السماء كطي السجل للكتب كما بدأنا أول خلق نعيده وعدا علينا إنا كنا فاعلين)
all these discussions lose me at the classic error of equating it with disorder. sorry. bye bye.
PLEASE RESHOOT THIS CLIP. You are adressing interesting issues, but you are all over the place and just ... it's a bad clip. Very bad. I don't want to downvote it, which is what it deserves, because I want to encourage science clips on TH-cam. But honestly, this is terrible. :/
noooo it acc really helped me, it's a great video