Carnot cycle and Carnot engine | Thermodynamics | Physics | Khan Academy

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  • Опубліковано 22 гру 2024
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    Introduction to the Carnot cycle and Carnot heat engine. Created by Sal Khan.
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КОМЕНТАРІ • 248

  • @musicforever1486
    @musicforever1486 5 років тому +111

    This video was released when I was in the kindergarten

  • @motopilot322
    @motopilot322 13 років тому +38

    You're animations are just fine man.. I've never taken formal physics courses, but for 10+ years now I've done my own research via books,magazines etc... Your videos by far are the most clear and to the point..your analogies are tough sometimes..but het..that's what pause and repay are for! Keep it up brotha! This is much appreciated!!

    • @khletus9061
      @khletus9061 2 роки тому +8

      10 more years have passed since your comment, how is your research going ?

  • @ninjabomberboy
    @ninjabomberboy 12 років тому +89

    Haven't started watching this explanation yet, but I already know its going to be a shitload better then my lecturers

    • @TurdFurgeson571
      @TurdFurgeson571 5 років тому +33

      Don't discount the fact that by now you're hearing this information for at least the second time. Try doing things the other way next time. Watch Khan first, then go to lecture. I promise you will enjoy lecture more than you do now. You will be prepared to work with this information on a new level in class and you will likely be able to ask better questions, which will only help you understand this stuff.
      Perhaps that may be the source of your trouble, too, that you don't ask questions. I don't know you, but I do know that most students remain quiet and confused, and thus frustrated at their professors or the content. It seems like most don't want to look stupid in front of peers. It's okay to look stupid when learning things you've never learned before. (You're all stupid! Why wouldn't you be? You've never done this before.) Regardless of the expectations you have for yourself, I promise you your instructor is not expecting you to completely understand this stuff after hearing it _one_ time. No one expects that. For the love of who or whatever you believe in, ask questions.
      If you're afraid to speak up in class, send an email, go to office hours, hell do your homework at office hours. "That's so awkward!" Oh well. This is why you pay tuition, not to sit in a class and hear something once, but to actually learn the material; learning requires this work on your part though, it's an active process. That's how to use your professors, and get the most out of a mortgage's worth of student loans you're going to have. Khan is great, but realize that you had to take time out of your day to participate in your learning. Your professor and Khan are both available, but it's up to you to actually utilize the resource.

    • @JivanPal
      @JivanPal 14 днів тому

      @@TurdFurgeson571 Some teachers really are just bad at teaching.

  • @juniorphysicist4055
    @juniorphysicist4055 3 роки тому +16

    The day after tomorrow is my physics exam. While revising thermodynamics , i was facing some difficulties to understand this topic. Thanks to Sal for explaining the concept in a easy way.
    Love from Bangladesh❤️❤️

  • @jiayu7597
    @jiayu7597 6 років тому +9

    You are so much better than my thermo professor....

  • @TET2005
    @TET2005 13 років тому +3

    Thank you sir. Your video is worth a million dollar instead of reading the boring physical textbook. As long the concepts are grasp properly, it will stay with you forever.

  • @rubaiyattasnim1297
    @rubaiyattasnim1297 4 роки тому +5

    For some reason I kept getting confused about how Q1 was coming into the system and Q2 was going out. This video helped so much!

  • @raiedahmednishat8883
    @raiedahmednishat8883 6 років тому +5

    I can't thank you enough!!! SAL!!! MA MAN!!!!
    seriously, I was really troubled by this... I'm so grateful that youtube exists and there's a channel called khan academy

  • @amassad127
    @amassad127 14 років тому +3

    All of these videos are really just incredible. I'm a sophomore engineer and I still find these videos really helpful! I wish there was some way to help you put out these videos.
    Really, really admirable--thank you

    • @annym.8170
      @annym.8170 5 років тому

      amassad127 donate khanacademy.org

  • @73Datsun180B
    @73Datsun180B 6 років тому +37

    I want to know what drugs carnot was doing, they seem pretty good!

  • @liaoyuqian4172
    @liaoyuqian4172 3 роки тому +1

    It’s kinda crazy when I fully understood the mechanism behind it. It gave me that”aha!” moment. Again, I am thoroughly impressed by Khan academy

  • @MalikRizwanElahi
    @MalikRizwanElahi 15 років тому +3

    all lectures deliverd by this HONOURABLE professor are soooooooooo nice.
    i like all the lectures and enjoyed. i realy appreciate wow. keep it up sir. May God give u long life to educate us

  • @yutongyang-b2e
    @yutongyang-b2e 5 років тому +1

    I love captions so much...especially when I find that I can open a Chinese captions.感觉世界充满关怀

  • @lilcote93
    @lilcote93 13 років тому +1

    im taking this right now with a prof that graduated from MIT as well ;)
    thanks for all the help sal

  • @SabbirAhmed-nw2cv
    @SabbirAhmed-nw2cv 3 роки тому +5

    I was struggling to understand this. Thank you for this!

  • @ahobimo732
    @ahobimo732 2 роки тому +3

    Such a great explanation. I'd forgotten just how incredible Khan Academy was.

  • @jamiegollings
    @jamiegollings 13 років тому +2

    Fell much more comfortable about my Therm exam on Monday now, thanks!

  • @omarkhanlilcurry
    @omarkhanlilcurry 8 років тому +214

    why do i pay tuition

    • @cbear9355
      @cbear9355 6 років тому +1

      You summed up college for me.

    • @amazingworld9463
      @amazingworld9463 5 років тому

      Paagal

    • @SaeedAcronia
      @SaeedAcronia 4 роки тому

      @@audacioustux Jesus. Poor guy just asked a question man.

    • @shubhaprada9423
      @shubhaprada9423 4 роки тому +1

      but I feel why do I pay even to college?

    • @chrisscott3725
      @chrisscott3725 4 роки тому +5

      For that piece of paper called a degree

  • @arjuncalidas2736
    @arjuncalidas2736 9 років тому +2

    10:13 I think as pressure is decreased, the volume is increased. You said volume goes down. But awesome work here.

  • @OpsOfCod
    @OpsOfCod 13 років тому +1

    wow i have to say this is awesome. I didnt think i would find a video that would explain carnot cycle to a point that i would understand. Thanks man !

  • @zpiazza
    @zpiazza 14 років тому +1

    these lectures should be put into number order

  • @williamjpiano
    @williamjpiano 12 років тому +1

    Very comprehensive video on Thermal cycles, nice work!

  • @abhisekupadhyaya11
    @abhisekupadhyaya11 10 років тому +29

    Great Video.... I would have failed my physic xm if I wasn't there....

    • @alijaved3356
      @alijaved3356 9 років тому +5

      +Abhisek Upadhyaya no shit sherlock

    • @janmay6349
      @janmay6349 8 років тому

      +Ali Javed
      Give him some ice for that burn

    • @alijaved3356
      @alijaved3356 8 років тому

      Janmay Patel lol :P i had forgotten about this

  • @iknownothing35
    @iknownothing35 5 років тому +2

    Shouldn't delta-U have a specific value considering for an adiabatic process Q = 0 always? In that example, W(AB) = 0; no work has been done. But the gas did do work considering the change in Volume... idk maybe I'm not seeing it.

  • @RKYT0
    @RKYT0 4 роки тому

    not finished repeating it but already IMMENSLY helpful

  • @anandapatmanabhansu
    @anandapatmanabhansu 3 роки тому +3

    Teach forever sir

  • @amritmcamc
    @amritmcamc 10 років тому +35

    I tripped on your shit. I understood it all. thanks.

  • @taltheking100
    @taltheking100 6 років тому +1

    Thank you for the video! You made it all so simple to understand

  • @cyrilsmith6396
    @cyrilsmith6396 10 років тому +6

    Thank u so much! U r doing a GREAT work there...

  • @ok_computer12
    @ok_computer12 6 років тому +1

    During the isothermal expansion process, does the system simultaneously absorb heat while doing work?

  • @jdfab_ulous
    @jdfab_ulous 11 років тому +5

    From B to C (adiabatic) process, why does Volume keep increasing since there's no change in heat transfer and there's no source / reservoir?

    • @arnatri1503
      @arnatri1503 7 років тому +5

      Fabrice Vieillesse when adiabatic expansion is taking place, the piston is just allowed move out. Therefore the gas expands increasing the volume.

  • @isadora13correa
    @isadora13correa 9 років тому +5

    THANK YOU!

  • @Quran722.
    @Quran722. 4 роки тому

    Simply made too simple by khan

  • @kaif2562
    @kaif2562 2 роки тому

    Thanks for helping me in learning it.

  • @huzaifa129
    @huzaifa129 13 років тому

    i would like to see such a talented professer!!!!!!!

  • @sergiolozavillarroel3784
    @sergiolozavillarroel3784 6 років тому +2

    8:43 "I should be talking about thermodinamics not drawing" lol

  • @s0m0c
    @s0m0c 13 років тому

    at 10:11 Salman Could have meaned "my pressure would have kept going down and my volume would have kept going up"

  • @glimpseofanpilgrimage5323
    @glimpseofanpilgrimage5323 5 років тому +1

    hey why the slop in the graph is more steaper at BC

  • @ptcala99
    @ptcala99 13 років тому

    shitty microsoft paint-esque program + 20 minutes = lucid explanation of the Carnot cycle....amazing!!!
    Thank you so much!!! I feel more comfortable with thermo than ever!

  • @orangeinfotainment620
    @orangeinfotainment620 Рік тому

    TYSM 🥰

  • @mikeb5174
    @mikeb5174 12 років тому

    also, at 7:00 : im taking pchem I right now, and we do define deltaU=q+w. so qab=-wab.

  • @theblackknight4295
    @theblackknight4295 6 років тому

    I just love your videos vai,love from Bangladesh.

  • @khellilg
    @khellilg 11 років тому +11

    Haaa if i had access to internet when i was a student....

  • @KVI3I
    @KVI3I 6 років тому +2

    One Question: By removing the Rocks, you have to use Work from the outside - would'nt that make the process irreversible?

    • @Vasu-qn6kj
      @Vasu-qn6kj 2 роки тому

      Wouldn't that also make it redundant?
      I mean Carnot cycle is utilised in an engine right.. you made an engine because you wanted to do work on something.. but if you have to do some outside work to make that happen.. then you're basically doing work to get work.
      Doesn't make sense to me.
      But ofcourse I'm obviously missing something.
      I just don't know what that is.

    • @phantomj8449
      @phantomj8449 2 роки тому

      They were actually adapted from the rotation of a train wheel, when as the rocks decrease, it indicates the axes start to have less push on the wheel (or backward resistance), closing in on 90 degrees to the forward motion of the train. Keep on going, and the wheel’s spin pushes the piston in the opposite direction, compressing the gas and then there’s the next 2 stages, completing the cycle.

  • @therandomguyrocks8206
    @therandomguyrocks8206 9 років тому

    When you started out with the pebbles (a load) doesnt it violate the assumptions of carnot cycle which says that the piston is weightless and frictionsless ...??? Adding load would lead to diff conclusions please correct if I am wrong..!

    • @therandomguyrocks8206
      @therandomguyrocks8206 9 років тому

      Also the walls are isolated within the assumptions how come the system get to any temp (T1 ,T2 or whatever)

    • @alijaved3356
      @alijaved3356 9 років тому

      +therandomguy rocks he didnt start the video with those assumption. I mean that assumption is about the piston being weightless and friction-less, there is nothing that says you cant do work on the system. This is just what i understand. u can confirm it from someone else

    • @alijaved3356
      @alijaved3356 9 років тому

      +therandomguy rocks only assumption is that it is a closed system, the pressure supposed to change for the cycle to complete. We need to do work on the system for it to go through these phases, this work is being done by pebbles, the only assumption while going from B to C and D to A is that these processes are isentropic and adiabatic.

    • @runecrafter1231
      @runecrafter1231 8 років тому

      +therandomguy rocks I think he added the rocks to make the system reversible.

    • @sahilsaha2879
      @sahilsaha2879 7 років тому

      It's all hypothetical geniuses

  • @vijgenboom2843
    @vijgenboom2843 2 роки тому

    Thank you ❤️

  • @amritas2400
    @amritas2400 4 роки тому

    Thanks a million 🙏❤❤❤❤❤

  • @Gahstupidcomments
    @Gahstupidcomments 12 років тому +2

    chemistry textbooks u = q + w
    physics textbooks u = q - w
    chemistry defines w as work done on the system
    physics defines w as work done by the system
    same equation
    MIND YOUR SIGNS

  • @milyas8817
    @milyas8817 6 років тому

    Thanks khan academy👌👌All ur lactrs r v Funnt and amazing

  • @jeanbernard3469
    @jeanbernard3469 Рік тому

    Thank you dear!

  • @anandapatmanabhansu
    @anandapatmanabhansu 3 роки тому +1

    Thankyou sir

  • @s0m0c
    @s0m0c 13 років тому

    in both process the volume is changing going up during expansions and going down in a compresion

  • @jasonpunza
    @jasonpunza 13 років тому

    all your videos are very helpful. thank you!

  • @Anujsingh-mo1vd
    @Anujsingh-mo1vd 5 років тому

    I understood, work done by the system is transferred the heat from hot reservoir to cold reservoir.

  • @therealjordiano
    @therealjordiano 11 років тому +1

    useful engine ... .. childhood comes to mind D,:

  • @internationalgolfconstruction
    @internationalgolfconstruction 8 років тому

    Can we say that the work done to the system from A to C is equal to mgh of the stones where h is the distance traveled by the piston?

  • @matthewheide6816
    @matthewheide6816 12 років тому

    you deserve a Nobel prize..nuf sayed

  • @welcomewehavecookies
    @welcomewehavecookies 11 років тому +1

    Thank you so much for your helpful tutorial! :D

  • @子阳-h7x
    @子阳-h7x 6 років тому

    great video! it help me a lot

  • @Oh4Chrissake
    @Oh4Chrissake 14 років тому

    How do we know that Q2 < Q1? That is, how do we know that a smaller amount of heat is transferred from the system, between C and D, than to it, between A and B?

  • @biswajitmarndi9146
    @biswajitmarndi9146 7 років тому

    wow!!! Thanks Sal.

  • @pyg1116
    @pyg1116 11 років тому +1

    I thought you couldn't draw the line from A to B because we can't measure the system while it's in flux...or do we always assume it's a quasistatic system...or can we draw the path because the system is kept at a constant temperature?

  • @s0m0c
    @s0m0c 13 років тому

    adiabatic process means isolated, so no heat transfer can ocurr,the system travels trough an isoterm and if the temperature doesn`t change for our system, neither do the Internal energy is going to change, so is constant.
    But in and adiabatic process the temperature of the system is not constant is not travelling along the isoterm anymore.

  • @bscutajar
    @bscutajar 2 роки тому

    What I don't get is that you can easily devise a system where the piston does work when kt moves both ways. So in that case both increasing and decreasing volumes would mean the piston is doing work. So you can just add and remove the same qty of heat and have the system do work, whicb would violate the first law.

  • @mitch.4615
    @mitch.4615 5 років тому

    Brilliant video, you have helped me so much! Thank you :)

  • @draegernaut
    @draegernaut 13 років тому

    THANK YOU, i understand now

  • @ahmedelbanna5156
    @ahmedelbanna5156 8 років тому +2

    How is adiabatic process digrammed with isothermic process in 2D and in isothermic process T is const while in adiabatic process T is variable so there must be 3D diagram For 3 variables P&V&T

    • @adityakhanna113
      @adityakhanna113 8 років тому

      It's a projection. The third variable is just mentioned.
      it's a bit messy to do 3d and 2d is understandable

    • @tejasgajra2731
      @tejasgajra2731 6 років тому +1

      A graph is always drawn between independent variables
      P,V&T altogether are not independent i.e. if two are known ,we can find the value of the third.

  • @kinzaarif8053
    @kinzaarif8053 8 років тому

    Great explanation!!keep it up

  • @sgsg5903
    @sgsg5903 7 років тому

    Very good thanks Very much!!

  • @kashiii2011
    @kashiii2011 13 років тому

    what do you do if it isn't a mono atomic ideal gas and if we are dealing with steam...?

  • @bindelapranay7921
    @bindelapranay7921 11 років тому

    its awesome i can learn phy very easily

  • @themeharsingh
    @themeharsingh 4 роки тому

    Why temperature should goes down in 1 st and 2nd step if pressure is decreased and volume incresed ( if reservoir wasn't there)

  • @Anujsingh-mo1vd
    @Anujsingh-mo1vd 5 років тому

    I understand. Work done went

  • @shreyanair3260
    @shreyanair3260 3 роки тому +1

    I used to think my life was full of problems.
    Then I found this comment section

  • @johnpartridge7052
    @johnpartridge7052 3 роки тому +2

    He sounds like Tom Hanks at 1.25x speed lol

  • @BigChungusthe3rd
    @BigChungusthe3rd 7 років тому +1

    so what's supplying the infinite energy of removing rocks then placing them back on? Doesn't seem like a very perfect system to me with zero energy loss. Very confused :'(

    • @darknebulae8037
      @darknebulae8037 7 років тому +1

      Yes it is hypothetical , the whole second law of thermodynamics is about how it is impossible to create a heat engine where the heat absorbed is totally converted to work done .

    • @phantomj8449
      @phantomj8449 2 роки тому

      They were actually adapted from the rotation of a train wheel, when as the rocks decrease, it indicates the axes start to have less push on the wheel (or backward resistance), closing in on 90 degrees to the forward motion of the train. Keep on going, and the wheel’s spin pushes the piston in the opposite direction, compressing the gas and then there’s the next 2 stages, completing the cycle.

  • @DonGuzmann
    @DonGuzmann 12 років тому

    first 2 mins ----> instant subscribe

  • @chaumpion
    @chaumpion 5 років тому +1

    congrats if you've just finished all 51 videos of this playlist x)

  • @vankadariprasannalakshmi5220
    @vankadariprasannalakshmi5220 2 роки тому

    Wow😍

  • @Growriginator
    @Growriginator 14 років тому

    Thank's from Germany!

  • @clementkoshy5438
    @clementkoshy5438 6 років тому

    If the internal energy of the ideal gas from 1-2 was zero ( the work done (1-2) was to increase the volume and decrease the pressure ) , then what is the internal energy of the ideal gas during adiabatic expansion ( process 2-3 )

  • @Mijal15
    @Mijal15 12 років тому

    From B to C where is the heat flow? The temperature is changing from T1 to T2 therefore its not isothermal. Once the reservoir is gone the system is completely isolated so the heat exchange would stop.

  • @mikeandino81
    @mikeandino81 14 років тому

    So A to B is adiabatic and so is B to C? I'm sorry but isn't T2 going into the system? Or is this a system definition issue? Thanks for the video, though. Very good!

  • @avestak
    @avestak 14 років тому

    Hi,
    Love your videos, is there a way to watch just thermodynamics ones? Thank you

  • @beyzayigit1912
    @beyzayigit1912 4 роки тому +1

    ı wish ı could like it for billion times hahhah

  • @shootshoot
    @shootshoot 15 років тому

    man you're really cranking these out, it's hard to keep up

  • @YoLninYo
    @YoLninYo 15 років тому

    Do you use the mouse or a tablet? love your work! so awesome!

  • @s0m0c
    @s0m0c 13 років тому

    Gracias.

  • @Dan.U.
    @Dan.U. 13 років тому

    Appreciate ur work!

  • @haysianblh5666
    @haysianblh5666 8 років тому

    can the whole carnot cycle be considered a quasi-static process?

  • @Anujsingh-mo1vd
    @Anujsingh-mo1vd 5 років тому

    Where does the net amount of work done by the system went in carnot cycle, from the law of conservation of energy.

  • @sinankuniyilathoot5188
    @sinankuniyilathoot5188 3 роки тому

    thAnks

  • @naghamghanayem298
    @naghamghanayem298 12 років тому

    when it goes from D to A is there still a resevoar ?

  • @amritbasavaraj9146
    @amritbasavaraj9146 11 місяців тому

    But how does this cycle interact with Kevin-Planck's statement that any system cannot absorb heat from a reservoir at a fixed temperature and convert it wholly into work?

  • @gazhill89
    @gazhill89 13 років тому

    Thanks

  • @alfredjackson1620
    @alfredjackson1620 Рік тому

    i need to ask how does this not violate the law of conservation of energy. Basically a piston can produce more energy than it needs to reset. So since the compression only requires a bit of work and the expansion produces more work we have a perpetual motion piston.

    • @pandaman9690
      @pandaman9690 Рік тому

      Well, I don’t think this violates the conservation of energy because the pebbles being removed and added is work coming from the environment. Also, the reservoirs are in practice not infinite, so eventually, it will equilibrate.

  • @M_0892
    @M_0892 12 років тому

    Thanx so much!

  • @diptilulla2895
    @diptilulla2895 7 років тому +1

    why is the system already at temp T1?

  • @ronaldbadic9828
    @ronaldbadic9828 11 років тому

    Good work.

  • @doganguler1
    @doganguler1 12 років тому

    there is no reservoir from D to A as no heat is exchanged in a adiabatic process.