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The classic Flanders and Swann explanation: https://www.youtube.com/watch?v=VnbiVw_1FNs Excerpts: No one can consider themsleves educated who doesn't understand the basic language of science - Boyle's law: the greater the external pressure the greater the volume of hot air. I was someone shocked to learn my partner not only doesn't understand the 2nd law of thermodynamics, he doesn't even understand the first! : Heat…
> The big deal is that all types of energy spread out like the energy in that hot pan does (unless somehow they're hindered from doing so) They don't tend to stay concentrated in a small space.
I am trying to loosely connect big ideas here so I might be wrong. If there is fundamental feature of a universal law, then that feature must manifest itself at all scales, as the above statements tries to put forward visually. Maybe this idea of flow spreading out is very general and some kind of summarization of that finer grain flow to coarser flow in the form of Green's theorem or Stoke's Theorem is very general.
Kinematic Flow and the Emergence of Time
A neat little corollary to this is to look a little more closely at what temperature actually is . "Temperature" doesn't appear too often in the main explanation here, but it's all over the "student's explanation". So... what is it? The most useful definition of temperature at the microscopic scale is probably this one: 1/T = dS / dU, which I've simplified because math notation is hard, and because we're not going to…
A neat little corollary to this is to look a little more closely at what temperature actually is . "Temperature" doesn't appear too often in the main explanation here, but it's all over the "student's explanation". So... what is it? The most useful definition of temperature at the microscopic scale is probably this one: 1/T = dS / dU, which I've simplified because math notation is hard, and because we're not going to…
I like the following related explanation ( https://www.reddit.com/r/thermodynamics/comments/owhkiv/comm... ) : > Many people focus on the statistical definition of entropy and the fact that entropy increases for any spontaneous process. Fewer people are familiar with thinking about entropy as the conjugate thermodynamic variable to temperature. Just as volumes shift to equalize pressure, areas shift to equalize surfa…
I remember watching videos of Leonard Susskind in which he talked about a similar phenomenon where circuit complexity itself increases till it maximizes. It behaves similar to entropy.
Complexity and Gravity - Leonard Susskind
https://youtu.be/6OXdhV5BOcY?t=3046
https://www.quantamagazine.org/in-new-paradox-black-holes-ap...
I could never wrap my head around the abstract concepts used in these explanations because they don't connect to what is actually happening at the atomic level. As far as I could tell the actual particles are undergoing a constant process of reducing the potential energy induced by force fields between them, which means everything is just jiggling all the time and spreading further and further apart. Heat is just som…
A neat little corollary to this is to look a little more closely at what temperature actually is . "Temperature" doesn't appear too often in the main explanation here, but it's all over the "student's explanation". So... what is it? The most useful definition of temperature at the microscopic scale is probably this one: 1/T = dS / dU, which I've simplified because math notation is hard, and because we're not going to…
I could never wrap my head around the abstract concepts used in these explanations because they don't connect to what is actually happening at the atomic level. As far as I could tell the actual particles are undergoing a constant process of reducing the potential energy induced by force fields between them, which means everything is just jiggling all the time and spreading further and further apart. Heat is just som…
Not really. They are in the process of spreading that energy as equally possible through as many fields as they can.
What is the Second Law of Thermodynamics.
The second law of thermodynamics says that the universe has an entropy gradient in the time dimension, while the cosmological principle says that the universe has no matter gradient in the spatial dimensions.
So together they describe how the universe (space-time) is structured, i.e. on the temporal dimension and the spatial dimensions.
It's also noteworthy that one enjoys the honorific "law" while the other is merely called a "principle". I wonder whether this is just an historical artifact or whether there is some theoretical justification for this distinction. (My intuition is that both are more "principles" [approximate tendencies?] than fundamental laws, since they don't say what's possible/impossible but rather what's statistically likely/unlikely.)
> Don't put me down. I could have snowed you with differential equations and diagrams instead of what you see everyday. We're being practical and visual rather than going the math route, essential as that is in chemistry. > The big deal is that all types of energy spread out like the energy in that hot pan does (unless somehow they're hindered from doing so) They don't tend to stay concentrated in a small space. I am…
It's probability. Increasing Entropy is a result of probability. That's all it is.
When you have a bunch of particles and you jostle the particles it is MORE probable for the particles to become spread out then it is to become concentrated in one corner. That probability is what is behind this mysterious force called entropy.
Why is it more probable? You just count the amount of possible states. There are MORE possible "spread out" states then there are "concentrated states". In Most systems there are more disorganized states then there are organized states.
Think of it in terms of dice. If you roll 10 dice, how likely are you to get some random spread of numbers vs. all the numbers concentrated on 6? Or all numbers concentrated on 1?
It's more probable to get a random spread of numbers because there are astronomically more possibilities here. For all numbers concentrated on 1,2,3,4,5, or 6 you only have a total of 6 possible states, all ones, all twos, all threes... all sixes... that's total six states.
Random spread occupies 46650 possible states (6^6 - 6). Hence by probability things are more likely to become disordered and spread out simply because there are more possible disordered states.
Entropy is a phenomenon of probability. People mistake it for some other fundamental law that mysteriously occurs. No it's not, it makes sense once you understand probability.
The real question is, what is probability? Why does it happen to work? Why does probability seem to follow an arrow of time, it doesn't seem symmetrical like the rest of physics.