It is common knowledge that you shouldn't use electrical appliances around water because it is very dangerous. Hair dryers, for instance, always have a tag warning the user to not put the hair dryer into water due to risk of shock or death. This is because water can conduct electricity.
Electricity is the movement of electrons from one atom to the next through any conductive material. Some materials are more conductive than other; metals, for instance, are known for their high conductivity. Electricity always takes the shortest path to the ground, and always takes the path of least resistance.
Water dissolves many materials well. Ionic materials, such as common table salt, dissolve into ions, which have an electric charge. Water can also dissolve metal ions. Water that contains dissolved ions conducts electricity very well. Water that is extremely pure and contains no ions does not conduct electricity well and is used for cooling some electrical equipment, but requires processing for great purity. Most water contains ions of some kind.
Electricity and Water
When electricity hits water, whether from a natural occurrence such as a lightning strike or an accident with an appliance, the electricity moves throughout the water. The water molecules themselves do not conduct the electricity; the dissolved ions within the water carry the moving electrons throughout the water. The electric charge becomes weaker as it moves away from the source, and the electric charge eventually dissipates.
Dangers of Electricity and Water
It is dangerous to be around water during a thunderstorm, or to touch water that has an electric charge. The human body is largely made up of water with dissolved salts, such as sodium, calcium and potassium. This means that the human body is an excellent electrical conductor, and electricity moves throughout the human body easily, causing damage, particularly to the heart.