Originally Posted by MrAntigone
I didn't draw or show a sketch in my first post. I just described one - and your initial report actually responded to that description which is the source of my confusion. I described a sketch in which two negative terminals of two separate batteries are connected to two different spots on the motor
. You said they could be the same spot so long as connections were clear of corrosion
. If two negative cables
are connected to the precise same spot motor-side, and battery
Selector switch is only selected to battery one or two but not all - it seems that in either case one positive of one battery is conductively connected to two negative terminals of two batteries. Without going further - am I mistaken so far? And if so, if both negative cables
can be connected to same spot, how so?
Think of it this way - if an electron leaves the negative terminal, another electron needs to enter the positive terminal of the same battery.
So if you have two batteries, but one is "disconnected" (by the switch) no electrons can flow onto the positive terminal of the disconnected battery (the switch is in the positive "side"), so all electrons will leave the negative terminal of the connected battery, and all electrons will flow back onto the positive terminal of that same battery.
If you do have two batteries, both connected, then electrons will leave the negative terminals of both batteries, and so however many electrons leave battery A will need to flow back into battery A, and likewise battery B.
BTW it is definitely NOT the "same electron" moving all the way from the negative terminal to the positive terminal. Just "an electron".
Metals such as copper have "loosely bound" electrons, i.e. electrons can flow easily from atom to atom of copper and so electrons "jump" between atoms. That is what makes copper a "conductor", it easily allows electrons to "jump" from atom to atom.
So one electron "jumps" (or is pushed) onto an atom at one end of the copper wire, essentially "pushing" an electron off of that atom onto the next atom, which pushes an electron off of that atom on to the next... and on and on in a chain reaction until one electron "jumps" off the wire attached to the positive terminal of the battery. Notice that the electron that left the negative terminal is at the wire end attached to the negative terminal and a completely different electron jumped off the positive end of the wire onto the positive terminal of the battery.
By the way, insulators are materials which strongly resist the free flow of electrons from atom (or molecule) to atom. Rubber as an example. It is possible for electrons to flow through insulators but it requires high voltages to make it happen. Think lightning
I am NOT a chemist or physicist so this description is a high level overview of what is actually going on.