Stump the Scientist: Static Electricity
This week, GE’s Facebook fan, Lino Sanft asked our Chief Scientist, “Why is it so difficult to harness and predict Static Electricity? It is inherent wherever opposing charges exist which would seem to make it a perpetual clean form of renewable energy. From that sense, we should be able to charge capacitors anywhere in a variety of environments.”
Response from Chief Scientist Jim Bray:
Lino, You are correct that positive and negative electrical charges exist within matter everywhere. However, they are normally attached to each other by positive-negative electrical attraction at the lowest energy state, such as in atoms. Since they are in the lowest energy state (often called the ground state), you can’t get any energy out by forcing them to a lower energy state, which does not exist. Static electricity is caused by moving these electrical charges to some other location and therefore higher energy state, often by a mechanical motion. This is like charging a capacitor, as you mention. Then the charges can be returned to the original ground state by a release of static electricity (which is the motion of the charges), which is just the release of energy we added by moving the charges in the first place. This is not a way to make new energy but can be used to store a little usefully , as in capacitors. This is hard to harness and predict, other than in capacitors, because it usually occurs randomly, such as in the friction of walking across a carpet in dry room. The biggest example in nature is probably lightning, which is the release of the static electrical charge built up between the ground and the clouds by the vertically moving air and water in a thunderstorm.