Re: Batteries and current flow

[Delmeister]

Different materials have different demands for electrons.  For example copper has a bigger demand for electrons than zinc.  In a copper/zinc battery, copper tries to take electrons away from zinc.  The nature of the battery prevents the direct transfer of electrons.  It forces the electrons from zinc metal to move through the external circuit (and a light bulb for example) to the copper terminal.

Now actually what happens is that a zinc metal atom gives up two electrons and turns into a doubly charged positive ion in an electrolyte.  The two electrons that go around the circuit combine with a doubly charged positive copper ion to form a metal atom.

The net result is that zinc metal gives off electrons and become positive zinc ions.  Copper ions accept the electrons and become copper metal.  In the end the zinc metal is gone as are the copper ions.  Zinc ions are formed as is copper metal.  Electrons have been transferred through the external circuit and the battery is spent.  If you force electrons the other way, you can recharge the battery and bring everything back to initial conditions.  In theory anyway, for this type of battery