This analogy makes a lot more sense given your argument. How exactly do you arrive at how many potentially freed electrons there can be in a given length and gauge of wire? Using Cu again, would you just find the aggregate amount of atoms per square millimeter and from that count just the two...
Let me get this straight, SophieCentaur. Reading what you are saying, is what I've been taught about current, namely that it is the freeing of electrons in the outer valence shells of atoms (like Cu) to other outer valence shells caused by a polarity difference between a negative and positive...