Creating the battery - Insert a penny into a cut on one side of the lemon. Push a galvanized nail into the other side of the lemon. The nail and penny must not touch. This is a single cell of a battery. The zinc nail and the copper penny are called electrodes. The lemon juice is called electrolyte. All batteries have a ' +' and '-' terminal. Electric current is a flow of atomic particles called electrons. Certain materials, called conductors, allow electrons to flow through them. Most metals (copper, iron) are good conductors of electricity. Electrons will flow from the '-' electrode of a battery, through a conductor, towards the '+' electrode of a battery. Volts (voltage) is a measure of the force moving the electrons. (High voltage is dangerous!)