Cells and Batteries 

Simple Cells

• A simple cell is a source of electrical energy
• The simplest design consists of two electrodes made from metals of different reactivity immersed in an electrolyte and connected to an external voltmeter by wire, creating a complete circuit
• A common example is zinc and copper
• Zinc is the more reactive metal and forms ions more easily, readily releasing electrons
• The electrons give the more reactive electrode a negative charge and sets up a charge difference between the electrodes
• The electrons then flow around the circuit to the copper electrode which is now the more positive electrode
• The difference in the ability of the electrodes to release electrons causes a voltage to be produced
• The greater the difference in the metals reactivity then the greater the voltage produced
• The electrolyte used also affects the voltage as different ions react with the electrodes in different ways