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My new video on Thermodynamics and the end of the Universe.

  1. Sep 12, 2013 #1
    I have just completed another physics video. This one is on Thermodynamics, and it is at


    It uses a physics simulation engine, along with high definition 3D graphics, to illustrate the increase of entropy, the conservation of energy, the principles of refrigeration and heat engines, etc.

    There is an emphasis in the video on the philosophical implications with regards to the end of all life in the Universe, hence the name of the video.

    I put a lot of effort into making the graphics for this video, so if you have the time, please watch the whole thing, and let me know what you think.

    It is 36 minutes long.


  2. jcsd
  3. Sep 12, 2013 #2


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    Staff: Mentor

    I watched the first few minutes. Nice job from what I saw.
  4. Sep 13, 2013 #3


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    Science Advisor

    wow, must have taken a lot of work to put together

    nitpick: "Even for chemical and nuclear reactions, the laws of physics work the same way backwards in time."
    This might not be exactly true for weak interactions. There's some observed CP symmetry violation, which implies some T asymmetry.

    Wow, I finished watching, and the physics are very good and accurate, and the graphics really involve the physics in an accurate way. This is much better than most popular videos, which show pretty graphics which don't make any physical sense.

    I'm proud of you for not calling entropy disorder, like 99% of other videos out there.

    Plural of nucleus is nuclei, not nucleuses.

    I don't think we need to worry about the stars running out. Humans won't last anywhere near that long.
    Last edited: Sep 13, 2013
  5. Sep 20, 2013 #4

    Thanks for the compliments. By the way, both "nuclei" and "nucleuses" are correct plural representations.

    In reply to your other comment, even if humans don't live long enough to see all the stars in the Universe run out of nuclear fuel, this is nevertheless still a fundamental problem for sentient life in the Universe in general.

    As for the few nuclear interactions that don't seem to be time reversible, my understanding is that if you swap all the electrical charges in the universe, take the mirror image of everything, and then also reverse the flow of time, then even these nuclear reactions end up looking like they are obeying all the laws of physics, along with everything else.
  6. Sep 21, 2013 #5


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    I agree. This means the laws of physics don't work the same going backwards in time. Physicists are trying to use this asymmetry to explain how the universe started with equal matter and antimatter, but eventually became mostly matter. If the laws of physics were the same going backwards in time, then they would have to find a different explanation.
  7. Sep 22, 2013 #6
    Nice job! I like the animations and the tutorial I am very much a layman in physics and appreciate this kind of thing very much. Here are some comments. Some of it might be just my lack of understanding, but it is hopefully useful input for you.

    When you say “objects at higher elevation have more energy” you are referring to potential energy. That is fine, but I think there could be a little more explanation about combined kinetic and potential energy. You do say that higher objects create more motion when they fall, but still I think it needs a bit more.

    I like the parts showing the car collisions and the spring giving energy, but I felt that something was missing in not showing the physics of the reactions.

    @4:40 when you say “here they absorb energy” it is unclear what is being demonstrated.

    At 11:30 when explaining the second law of thermodynamics, you say that it is the only law that does not work backwards in time. Then you open the barrier so that the balls spread out through the entire box, and you say “no matter how long you wait, the balls will never again gather together in one small area”

    The fact of the matter is that if you run time backwards, the balls will gather back in the small area, just the same as the billiard balls did. There is a difference between “wait a long time”, and “going backwards in time”, and I think you made a switch there.

    As far as the universe increasing in entropy until all energy is dispersed, that is our current situation in the universe as far as our current understanding, but I believe that we must ask how we came to be in our current state of relatively low entropy such that useful work is possible. You can talk about the big bang or some other explanation, but whatever the cause, if it happened once, then it is entirely possible that it could have happened a googleplex to the power of a googleplex many times before, and will again.
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