> the idea that any system tries to minimize its energy is just nonsense.
Very interesting, I feel somewhat misled if this is true.
Very interesting, I feel somewhat misled if this is true.
While it is true that a system doesn't minimize the energy of the entire system, as energy IS conserved, except apparently for a miniscule amount due to the universe expanding, it is also true that locally it often looks like minimizing energy in some sense.
If you have a vibrating spring on a table, after a while it will have stopped because it has created motions in the air and in the table, spreading out at the speed of sound in whatever material it encounters, and some of it also at the speed of light in the form of thermal radiation.
So, looking only at the spring, it is minimizing it's energy by returning to a stable quiscent state. In the same way, if we look at a sphere with radius as "the speed of light times the time from the start of the experiment", all energy can still be accounted for within that volume.
One system, several perspectives.
I think the minimization model is often used because the statistical model of entropy can be hard to explain, as it simultaneously allows complex relatively ordered systems like us humans to exist, while at the same time explains the almost complete disorder of thermal energy and how it disperses.
Thus, since the energy minimization of the local state can be used as a relatively truthful proxy, we learn that model first. With the possible bonus that it also allows one to temporarily avoiding some rather (afaict) gnarly math until you actually have the tools you need to understand it.
And if you want to calculate if a thermodynamically spontaneous reaction will appreciably take place, you also need to understand the actual intermediates between A + B -> C, and find reaction barrier heights for all of them, and weight them appropriately. This is still very hard to do so information of this sort is mostly determined by experiment rather than calculation.