Is water a conductor?

We are told to be extra careful about electricity when there is water around. Is water really that good a conductor?

It depends very much on what is in the water. Pure water is a pretty good insulator, but many chemicals can turn it into a conductor. This happens because the chemicals themselves can separate into opposite charges, and then the two charged species can move. For example, dissolving table salt (sodium chloride) in water makes positive sodium ions and negative chloride ions. In one of the activities in this section it is shown that you can get enough current through salty water or vinegary water to make the buzzer buzz or the light emitting diode glow. The current is not not very big, but then according to the page about electrical safety, even a small current can be dangerous. Indeed, an electrical shock is due to electrical current that is flowing through our blood and bodily fluids.

Static electricity

Static electricity gets to be a nuisance in the winter, when walking across a rug will give you a large enough charge that you get an alarming shock when you touch any large conducting object. The origin of the static charge is discussed elsewhere. The reason it only happens in the winter is that the humidity is low inside. During the summer there is more water in the air, and this gives rise to a thin layer of water on all surfaces. It's just enough to conduct away the static electricity as fast as it is created. Adding a humidifier to your heating system will decrease the static problem, as well as make the air seem warmer.

The section on conductors and resistors