I think I might of asked the question wrong.
I'm still not sure how to word it, but thinking about it more, I think my question
might not be so much an electronics question but more a question of how electricity
really works.
The understanding I left school with of electricity was that any "matter" that holds a negative charge will release any excess electrons to any matter that has less electrons then the atoms balanced state.
welcome
not quite right
ALL matter is made up of positive and negative charges, and barring any external influences the positive and negative charges are balanced. lets take a block of plastic and a block of copper. The they both are made up of atoms a nucleus made up of protons and neutrons surrounded by a "cloud" of orbiting electrons. The number of electrons for each atom = the number of protons in each atom nucleus (core). That goes for both the insulator , the plastic and for the copper a good electrical conductor.
So why you ask does the copper conduct and the plastic not conduct.
Well very simply without getting into deep physics.
Its because in some materials, like metals and a few other things, have a lot of loosely bound electrons in their outer shells ( electrons form "shells" (layers) around the nucleus. These electrons are able to reasonably freely move between the atoms. In an insulator it is the opposite and those outer shell electrons are not free to move. so when a current ie. a supply of electrons is applied to the copper block, say from a battery negative terminal, electrons are "pushed" The push comes from the voltage ( the potential difference between the terminals of the battery or other supply) in from one end of the block electrons start moving along from atom to atom the electrons are attracted to the positive end of the battery terminal connected to the other end of the copper block, where there is a deficiency of electrons.
With that image of how dc power flows I can't see in my mind why the negative wouldn't
pass to any positive terminal. Maybe I'm way off in interpreting the pictures I see of how electrons flow, or maybe it is to do with the chemical balance of a battery. To be honest, I'm not too good with terminology so it's hard to describe.
Electrons will flow through the wire and a current of electricity is produced. Inside the battery, a reaction between chemicals take place. But the reaction takes place only if there is a flow of electrons. Batteries can be stored for a long time and still work because the chemical process doesn't start until the electrons flow from the negative to the positive terminals through a circuit.
hopefully that helps a bit
cheers
Dave