I am a high school student trying to wrap my head around the second law of thermodynamics for the past few days to no avail. Having only a cursory knowledge of calculus, and chemistry and physics in general doesn't help either.
The second law of thermodynamics says that entropy of the universe always increases. For constant pressure and temperature conditions, Gibbs free energy equation is used to calculate whether the reaction is spontaneous or not, meaning whether it will occur or not.
The more I try to read about it, the more proof I find against above paragraph. After having read about the Poincaré recurrence theorem, Maxwell's demon, and this excellent Quora answer, I would say that the whole law of thermodynamics is a farce. A plot by Gibbs and Helmholtz and Boltzmann and Maxwell to dupe the students while they laugh from the heavens. Please excuse my rambling. It's the product of tearing out half my hair trying to understand this.
From what I have read, it seems that the second law is not really a law, but a statement about the most probable arrangement of a given system. Of course, I don't claim to understand anything from the sources I have mentioned, nor do I think I will understand before at least an undergraduate course in partial differential equations, calculus and all the other prerequisites required to even start.
So my goal in asking this question is asking if anyone is capable and willing to write a concise and simple explanation for a high school student which would also sort out all the fallacies I have mentioned above, or can direct me to someone who can. I understand that this might be a Feynman-esque feat not suitable for this site and I apologise for that.
EDIT: I have gained a somewhat good understanding of the second law (for a high school student). So my question is not as open ended as it was. What I really want to ask now is: What does it mean for entropy to decrease, if there was a small enough isolated system so that the chances of non-spontaneous events happening was not 1 in TREE?
Would all laws of thermodynamics go out of the window? It seems to me that this weakness (I don’t know how to phrase this) of the second law is largely ignored because the chances of this happening are approximately 0.
Of course, all this rests on the assumption that entropy can decrease, which is what I have gathered, although not all people agree, but many do. If it can decrease, doesn’t that mean that as the system gets smaller the laws of thermodynamics get weaker?
Where do you draw the line after which the laws of thermodynamics are not reliable?
Also, when I use the Gibbs equation to find the boiling point of water at NTP, would that boiling point change as I reduced the number of particles?
Is my boiling point wrong? Boiling point is a bulk property, but you could easily substitute a chemical reaction in that.