Resistance is opposition to the flow of current and is measured in ohms (Ω). One ohm is defined as the amount of resistance that will allow one ampere of current to flow if one volt of voltage is applied. As resistance increases, current decreases as resistance and current are inversely proportional.

Current is the rate of flow of electrons per unit time and is measured in amperes (A). A coulomb (C) is the quantity of electricity conveyed in one second by a current of one ampere.

All electricity is the movement of electrons which are subatomic particles that orbit the nucleus of an atom. Electrons occupy various energy levels called shells and how well an element enables the flow of electrons depends on how many electrons occupy its outer (valence) electron shell.

Connecting the 8 batteries in series multiplies their voltage while keeping their current the same yielding a 120V 25A configuration. Connecting the 8 batteries in parallel multiplies their current while keeping their voltage the same yielding a 15V 200A configuration. Using a series-parallel connection, 4 batteries can be connected in series and 4 can be connected in parallel resulting in a 60V 100A configuration.

All conductors have resistance and the amount of resistance varies with the element. In general, metals make the best conductors of electricity and non-metals make the worst conductors of electricity.