What is entropy? – Jeff Phillips

What is entropy? – Jeff Phillips

View full lesson: http://ed.ted.com/lessons/what-is-entropy-jeff-phillips

There’s a concept that’s crucial to chemistry and physics. It helps explain why physical processes go one way and not the other: why ice melts, why cream spreads in coffee, why air leaks out of a punctured tire. It’s entropy, and it’s notoriously difficult to wrap our heads around. Jeff Phillips gives a crash course on entropy.

Lesson by Jeff Phillips, animation by Provincia Studio.


  1. Viktor Klemming on October 6, 2021 at 8:01 am

    Jeff Philips: "The chances that the icewater will make the coffe warmer are 0,0000000000003."
    Me: "So you’re telling me there is a chance!"
    Jeff Philips: "You did not understand one word in this entire video did you?"
    Me: "Not a single word."

  2. EpicRaptorMan on October 6, 2021 at 8:04 am

    I see it as a way of the universe trying to balance itself.

    The air compacted in a tire release to balance the air outside. A sort of homeostasis.

  3. pussy cat on October 6, 2021 at 8:05 am

    This is another way of saying to sleep now

  4. David Johnston on October 6, 2021 at 8:08 am

    The physics definition of entropy is just Shannon entropy H(X) . Us cryptography types use Renye entropy H_alpha(X) (as defined by Alfred Renye) which is an infinite class of entropy formulas, the most conservative of which is where alpha=infinity and is called min-entropy. This is analogous to the probability of being able to guess a number correctly from a uniformly distributed source and so directly relates to being able to guess a key. H_1(X) is the same as Shannon entropy but it’s not much use in cryptography.

  5. Garo Gary Voskorian on October 6, 2021 at 8:08 am

    If we put 2 glasses of water, one cold and other hot in a containment totlally 1000% in a vaccum, what will happen?🤔

  6. God loves me on October 6, 2021 at 8:09 am


  7. Rogan on October 6, 2021 at 8:10 am

    Is this how the big bang happened? time is endless so even a miniscule chance has to happen at some point so even though all the energy in the universe happening to come together at the same time is 0.1^21345367658346534645 it is still possible and has to happen eventually even if it takes 3120948258734986793486745 trillion years, and at some point suddenly the universe got extremely hot instead of cooling down, this is me just making stuff up but thoughts?

  8. HCSR2 on October 6, 2021 at 8:13 am

    Ok, I’m with you, but what is entropy?

  9. Synthetase2 on October 6, 2021 at 8:13 am

    This is such a weird explanation of entropy

  10. Brian Letter on October 6, 2021 at 8:15 am

    I have seen worse!
    A difficulty I had at first with this presentation is his little packets of energy ‘moving about’.
    Few people see energy as ‘ little packets’ that ‘move about’.
    It’s possible to look at Jeff’s model as ‘very small’ – actually ‘one or zero’ binary packets.
    You are all, I take it, familiar with the ‘two valued, 0 & 1 numbering in computer arithmetic.
    Well, that is the way Jeff’s describing his ‘System with ‘Entropy here’.
    It is easiest to consider entropy in arrangements of multiple particles because it is not easy to imagine different ways of arranging just ONE particle(!)

    NB#1 It might help to consider the dimension of entropy is exactly the same as temperature i.e. ‘Energy per Particle’. The difference arises with larger numbers of particles.

    NB#2! To keep it simple we consider the energy (i.e. the temperature of a particle) as ‘its kinetic energy’ = half the mass x the velocity squared (KE = 1/2mV^2) of every ‘individual’ particle. You should already know that heat energy is the energy/of vibrating atoms, molecules or any particle that moves independently.

    The next concept is ‘Thermal Equilibrium’ meaning all the particles in a group (or ‘system’) – System merely means all the parts influence each other some how. Like I said before, a single particle, by itself, has a temperature together with other particles they may collide ans therefore exchange energy – now we have a ‘ system’ (of particles, atoms, molecules etc.) If, by chance, they all have the same ‘kinetic energy’ they have the same ‘temperature’.

    Maxwell & Boltzmann worked out what happened if these particles were colliding all the time, their total energy remaining the same. So the time averaged energy of the particles remained the same, meaning the temperature stayed constant too.

    Between them, Maxwell & Boltzmann worked out what would be the energy distribution of the particles would be if they were colliding randomly i.e. free from external influence because clearly if the particles were constantly colliding, they would be constantly changing their energy at a phenomenal rate.

    Entropy, similar to temperature describes a system of particles where the long term average is NOT the same. Simply put, some have a higher (or lower) temperature. The SYSTEM is not in equilibrium – it no longer has a uniform temperature, the various places (particles!) are at different temperatures!.

    A simple example is a glass of water where there is a warm layer gloating on a cold layer. Impossible to give it a (single) ‘temperature”. You may stir the water so that it mixes well, then it will have a single temperature. However, unless you knew exactly how much warm and how much cold water (difficult!), you will have no idea what the resulting temperature from your mixing will be!

    Think about it.
    Funny stuff, heat.

  11. The 14th Master on October 6, 2021 at 8:16 am

    So basically no on can die…ressurect…and elevate into the sky post-death? 🤔 #Bummer

  12. Crystal Bramhill on October 6, 2021 at 8:18 am

    If you had a tool to help you learn and be successful/pass thermo, what would you need in the tool? What issues/challenges did you experience taking thermo? What do you do when you are "stuck" and how do you get unstuck? If you have disabilities, what are accessibility needs to utilize an online tool? Why is thermo a difficult coarse?

  13. Captain Does Youtube on October 6, 2021 at 8:18 am

    When it’s irregular: *BOSS MUSIC INTENSIFIES*

  14. KuroMeta Productions on October 6, 2021 at 8:18 am

    fair enough

  15. sheema fathima on October 6, 2021 at 8:19 am

    Thank you

  16. Barão do cerro azul on October 6, 2021 at 8:20 am

    Time travel?

  17. Sterly on October 6, 2021 at 8:21 am

    The universe cannot be infinitely old or all useable energy would have been lost already (entropy).  This has not occurred.  Therefore, the universe is not infinitely old. Therefore, the universe had a beginning.  Something cannot bring itself into existence.  Therefore, something brought it into existence.

  18. trackthompson on October 6, 2021 at 8:25 am

    Is this why some people spontaneously combust?

  19. Simon Hansen on October 6, 2021 at 8:26 am

  20. Silent Whisper on October 6, 2021 at 8:28 am

    Only me who followed everything in the video while on 5hrs of sleep and just sees all the comfused ppl in the comments? xD

  21. Sayed Elghairb on October 6, 2021 at 8:28 am

    Glory be to Allah 🙏🤲🏻❤️❤️❤️❤️❤️❤️❤️ Creator of everything

  22. Fahad Zubaid on October 6, 2021 at 8:30 am

    I have to say this. This was very poorly done to try and get the concept of entropy across.

    Heck, Tenet did a better job of explaining entropy than this.

  23. Wookie z on October 6, 2021 at 8:31 am

    There’s a universe out there where someone threw an ice cube into a forest and ended Earth.

  24. BryTek Labs on October 6, 2021 at 8:33 am

    xue hua piao piao vibes from that one guy

  25. Mathieu France on October 6, 2021 at 8:33 am

    That was a nice trailer for TENET… I cannot wait to watch this movie in the past!

  26. Ángela Iglesias on October 6, 2021 at 8:34 am

    You can explain It easier with socks. When you keep all your socks in one drawer, this drawer is concentrated in socks and there are less possibilities for the socks to be (less entropy and higher family order). If you have your socks all over the place, there are many possibilites for the socks to be (higher entropy and higher disorder)….they are disperse and the energy to find them is so high… that you even prefer to say that you have lost some socks. 😂😂

  27. cdorman11 on October 6, 2021 at 8:35 am

    1:08 Energy isn’t stored in bonds. Common misconception. If that were true, why would you need to add energy in order to break the bonds?

  28. Rick Postier on October 6, 2021 at 8:35 am

    I believe that entropy is not only mathematics, but also energy that humans haven’t figured out how to harness. Like the energy in a single lightening bolt for example. Entropy is the unknown … more than it is really known.

  29. logan nasty on October 6, 2021 at 8:36 am

    The intro music and the voice have an unpleasant tone

  30. Andres Arias Calderon on October 6, 2021 at 8:36 am

    primero se debe ver TENET, despues ver este video, despues ver TENET nuevamente, para poder entender este video :v

  31. Fuzuli on October 6, 2021 at 8:37 am

    It’s harder than quantum physics damn.

  32. Abdulkarim Shaban Mhandeni on October 6, 2021 at 8:38 am

    Some scholars in Translation studies use this concept metaphorically to conceptualize translation (entropy vs negentropy). I can’t get it.

  33. Hind Swaraj on October 6, 2021 at 8:38 am

    If enthalpy increase the entropy will increase or decrease???

  34. Yours Truely on October 6, 2021 at 8:39 am

    So microstates is not the right concept if you mix it with statistics.

  35. The Science Man on October 6, 2021 at 8:41 am

    This is by far the best explanation of entropy I’ve ever seen. I’ve been trying to understand the complex concept for a while now and now I finally get it! Science seems to have an endless list of awesome concepts doesn’t it?

  36. Bradley Cossins on October 6, 2021 at 8:42 am

    Entropy is the natural order. I simply… Categorize the process.
    -Alexander Nox

  37. A z A on October 6, 2021 at 8:43 am

    This info went through one ear and out of the exact same ear. It did a U turn because my brain said "no".

  38. M. Fatih DİNÇ on October 6, 2021 at 8:45 am

    One question: Let’s say two identical substance with same energy (and Temp. ) interacts,

    according to your explanation, it’s more likely to have different quantas for them after interaction,

    implying that they will have different energy and temperatures, which is not the case in real life since they will have the same temperature…

  39. KING Merlin on October 6, 2021 at 8:45 am

    OK…I think I understand why Christopher Nolan movies are confusing…. I’m not sure…I think

  40. حسين باهر جابر on October 6, 2021 at 8:46 am

    Energy tends to be a free
    So —> to spread
    So—> to be a messy
    So—> it doesn’t tidy

    Ok, but why there are many things -normally- in the life so tidy, systemic and organized (like the solar system and any organism)?

  41. Andrew Meliokrates on October 6, 2021 at 8:46 am

    The new physics knocks at the door.
    Two new physics lessons.
    How to solve the two EXPERIMENTALLY PROVED physical paradoxes, which are described in the two links below:

  42. misotrash on October 6, 2021 at 8:49 am

    I was literally Googling what entropy is yesterday and today I got this in my recommendation

    Nice spying on me Google

  43. Carolina Silva on October 6, 2021 at 8:50 am

    mesures the difusion of *energy*

  44. The Common Fellow on October 6, 2021 at 8:51 am

    Sir, does entropy have anything to do with Schrodinger’s Equation?
    If so, how are the concepts interrelated?

  45. Techy504 on October 6, 2021 at 8:52 am

    LOL , Chinese Eggman

  46. Poonam Sharma on October 6, 2021 at 8:55 am

    I’m watching this video and I’m in class 10 still….
    —nikhil VASHISTHA
    From india…..

  47. Jocelyn Joseph on October 6, 2021 at 8:56 am

    Consider a reaction which is endothermic. Yet it continues until the substance temperature drops to minus twenty degrees Celsius. How???
    ENTROPY at its best👍💯.

  48. Hamza Javed on October 6, 2021 at 8:57 am

    I am going to unsub this channel after this video😏

  49. Yours Truely on October 6, 2021 at 8:58 am

    So you proved statistics do not work on molecular level.

  50. Suraj Choudhary on October 6, 2021 at 8:59 am

    Entropy is not so complicated.. but video Is..