Exhibit: Electrochemical Ladder
When you hold a pair of rods your body fluids become the electrolyte between the metals and make an electrical cell or battery. All batteries consist of two different types of material (usually metals) separated by a liquid that conducts electricity.
Some metals give up electrons easily at their surface to drive an electric current, others less so. The metals on the exhibit are arranged in order of chemical reactivity, so the further apart they are on the ladder, the higher the voltage.
The biggest effect in the exhibit occurs when you hold the Magnesium and Gold rods. If you swap sides, but keep to the same metals, the current reverses direction.
While a battery drives an electric current, chemical reactions occur where the two metals meet the conducting liquid. Don’t panic when you use the exhibit. The amount of current which flows through you is so tiny that you won’t be chemically altered!