How I am interested in understanding what is the actual mechanism behind increasing potential in simple galvanic cell connected in series. Almost all explanations I found on internet are more like recursive "explanation from definition". First we define that each cell adds potential difference and then it becomes the actual explanation. I am feeling that this lacks an actual chemical insight of why electrons experience more EMF in such circle. So I am trying my luck here. This duplicate left with no answer.
To make question more concrete consider the following:- suppose you can examine only one cell in galvanic (classical Zn/Cu) battery you do not know where its anode and cathode are connected. However you do know that the circuit is closed. Will it be possible by observation of chemical/electrical/atomical process in it to know that it connected in series or not? In other words will it be possible to determine that this is the only source of EMF? If yes what chemically/electrically changes will it experience vs the condition where it works alone.
And yes I do not have any real background in chemistry or electronics so use simple English :)