Thermodynamics concerns how systems that contain matter interact with thermal energy. Traditional thermodynamics has become a science based upon the statistical entropy change, which is actually a complication of the simple. Specifically, it is a mathematical construct to which we continully try and determine a logic that fits, rather than take the scientific approach of construct a logic and then determine a math that suits that logic. Interestingly,
Planck points out, that we had two choices when conceiving thermodynamics, and in so far as this author is concerned the choice would have been different if our 19th century greats understood the ramification of lost work into our atmosphere, as defined by W=PdV.
Our new perspective focuses upon energy change, with the understanding that work generally involves an irreversible process, and that this has no real basis in entropy change! In other words, thermodynamics can be simplified by omitting entropy in all of it guises. This includes the entropy based second law but not the original premise of the second law that being there is no such thing asw perpetual motion at least here surrounded by Earth's atmosphere.
In simplest terms the problem actually started with the misunderstandings concerning lost work (PdV) by expanding systems. If lost work originally had the clarity of it being due to the displacement of our atmosphereís [P(atm)dV] mass, which ultimately lends itself to the heating of the atmosphere. Then we may have never wrongly perceived that the energy was lost inside the expanding system that led to that bizarre association of energy with randomness.(reference my 2015 paper "Second law and Lost Work" in Peer reviewed Journal Physics Essays)
Note: Heating of atmosphere is often due to intermolecular collisions being inelastic: (Reference my 2017 and 2018 papers in peer reviewed on-line journal Progress in physics: Papers concerning rewriting kinetic theory: see my papers)
It is interesting that today some now understand that work is done onto the surround atmosphere (W=PdV) but seemingly few are willing to make the next necessary mental leap that being the work is irreversible AKA lost work. So today some stand transfixed in macabre thought, i.e. that there is still an energy associated with an expanding systemís randomness, and yet the work done is onto the surroundings. In part this is do the hideous refusal to state the obvious that the surrounding tends to be our atmosphere! And the refusal to let go of entropy based thermodynamics and its associated second law. Sorry for repitition but sometime it is necessary.
Traditional thermodynamics really put the cart ahead of the horse. The reality remains that an isobaric gaseous system tends to become more random when thermal energy is added, and by more random it is meant that the isobaric systemís volume has increased, hence work [P(atm)dV] is done. Of course that same gaseous system maybe both closed and constrained i.e. isometric thus the additional thermal energy results in an isochloric/isometric pressure increase, hence no work is actually done but the potential to do work increases.
Arnold Sommerfield was right (see quote to RHS). However, this author has come to realize that traditional thermodynamics is truly a complication of the simple. The science of how matter and energy interact should be a relatively simple science unfortunately it is an example of: "What a tangled web we weave, when at first we fail to perceive". I often compare thermodynamics to a computer that being something that starts with simple bits and bytes but has seemingly manifested itself into an unnecessarily excessively complex machine.