# Definition of Static Electricity

The result of an imbalance of electrons between objects is called static electricity. It is called "static" because the displaced electrons tend to remain stationary after being moved from one insulating material to another.

Please can any one explain to me what does it mean by the word stationary in the definition? Does it mean that the displaced electrons do not spin around the nucleus in another material's atom?

• No it means the charge isn't moving as part of a current. There is an excess of charge in one location and it's trapped, unable to move to an area of excess opposite charge. – Brandon Enright May 3 '13 at 18:29

## 2 Answers

What we mean here by the word stationary is that the (macroscopic) charge density is constant , even if charges are moving actually.(An explanation for the word macroscopic comes in the next paragraph). A famous example is a rotating sphere with charge density $\rho$ , which is (electrically) equivalent to a non-rotating sphere.(But has a magnetic field due to it's current)

The point is that these models of matter are macroscopic models , which means that when we speak of charge we consider a big enough chunk of matter, much bigger than real charge carriers like electrons ( and yet small enough to consider variations of charge density in the matter). So it is correct that electrons spin around the nucleus , but the atom (or maybe some bigger group of atoms) as a whole is considered as a charge in our model.

charge inside the conductor moves with random speed which is known as thermal speed. But average velocity made by the randomly moving charges is zero as they are not alined in the absence of external force i.e. voltage supply. static electricity also termed as electrostatics creates electric field, static charges resides on outer surface of the conductor