@Ragman,
Yes, I know, I was well aware of the date of the post; I mentioned that in my own comment.
I'd argue that knowledge knows no time limit and ask; you'd prefer I create a new post addressing this one?
Why not merely expand on what's here which notifies the parties, including the guy who hasn't really understood yet?
Further, nobody really gave a good explanation (I think everybody was busy being a little too high and mighty).
Here you have a guy who is expecting a negative terminal to discharge into a positive one (a la magnets with a South pole locking into place with another's North) and you guys are simply saying 'no, that's not how it works.'
Imagine electrostatics, where you have 2 Wimshurst machines. Each have 1 positive and 1 negative. Now if you hook the negative of one machine to the positive of its own a spark will occur. Additionally, as far as I know, if you hook the negative of one to the positive of the other, electricity will flow.
However, in the case of batteries, this does not work. This is non-intuitive so it's reasonable that there be confusion.
Now, after rereading one explanation (can't remember who's) the writer started off as though he knew where the disconnect was, that we didn't understand how batteries work.
He seemed to suggest there is a unique pathway the electrons take. I'm going to explain it in a way that's probably wrong technically but might be what he was trying to illustrate.
He made it seem as though there we're a barrier that only permitted electron flow in one direction, say, to the right (if you had a battery with negative on the left and positive on the right, the electrons would somehow go right (through positive) and wrap back around to negative.
If you short that with a wire, the electrons can go right and wrap around to the negative. However, if you bring the positive terminal of a different battery up to the original, the electrons wont flow because they can't go left due to the chemical makeup.
If this is right, it wasn't explained this simply by anyone and it still doesn't necessarily address why (or it did and that's the part we missed and/or can't wrap our heads around) and I also still can not make sense of it (it's probably wrong).
I think us laymen imagine a negative terminal having an excess of electrons and dumping into a positive terminal and 'that's all there is to it, right?' So I put the end of one battery up to another, why arent those electrons going?
Why can I have one battery and one wire, short it and electrons go but if I take ONE end of the wire off of positive and connect it to a different positive why wont the electrons flow? What is different here from 2 VanDegraph generators?
Its rather confusing ostensibly.