Objectives

  • To understand that when certain insulating materials are rubbed against each other they become electrically charged.
  • To appreciate that negatively charged electrons are rubbed off one material and onto the other.
  • To identify that the material that gains electrons becomes negatively charged and the material that loses electrons is left with an equal positive charge. 

Static electricity was first discovered (or at least was first recorded) by the Greeks back in 600BC, they found that when a piece of fur was rubbed again a piece of amber (fossilised tree resin) the two showed signs of attraction – this was static electricity.

Static electricity comes from the transfer of charged particles which are then held (or stored) by a material. Two neutral insulating materials that rub against one another allow a transfer of electrons from one material to the other. The material that loses electrons has lost negative charge and therefore becomes positively charged. The material that gains electrons has gained negative charge and therefore becomes negatively charged.The materials are usually insulators that restrict the flow of electrons. However, if two materials are rubbed against one another, the friction causes a transfer of some of the electrons. The electrons are then trapped because it is an insulating material and the charges cannot flow.

Watch this short video clip for another explanation

One practical you will hopefully observe and maybe even get involved with in class is with the Van De Graaff generator. The following video is quite good at explaining how it works and the importance of potential difference:

A couple of questions for you to consider before moving on to the next topic (the uses and dangers of static electricity) are:

  1. How does lightning work?
  2. Where is static electricity used in everyday life?
  3. Is static electricity dangerous, if so where?

Further reading: