Why does water conduct electricity?
Ordinary water contains dissolved ions: electrically charged particles that can move through the liquid. Their movement carries electric current. Highly purified water conducts electricity very poorly.
- The scientific idea
- Electrical conductivity
- Fields of science
- Physics, Chemistry
How it works
A clear glass of tap water can contain dissolved salts that you cannot see. When table salt dissolves, its sodium and chloride ions separate and can move through the water. In an electric field, positive and negative ions drift in opposite directions. The liquid can therefore carry current while remaining electrically neutral overall.
Look closer
Removing dissolved ions greatly reduces water's conductivity. Even pure water has a tiny population of ions formed by reactions between water molecules, so its conductivity is very low rather than exactly zero. The familiar idea that water conducts well largely reflects the substances dissolved in everyday water. Transparency tells you little about how many charge carriers are present.