Static Electricity

Static electricity is the result of charges not being free to move. Consequently the charge accumulates in one place, often causing a spark or a shock when they do finally move. 

1) Build-up of static is caused by friction

• When two insulating materials are rubbed together, electrons are transferred from one to the other.
• The material with the extra electrons attains a negative charge, whilst the other material gains a positive charge.
• Electrically charged objects attract small neutral objects placed near them. Therefore, the materials involved affects which materials gain each charge.  EXAMPLE:  Polythene rod and duster. Electrons move from the duster to the rod.  Acetate rod and duster. Electrons move from the rod to the duster. 

2) Only electrons move

Positive and negative electrostatic charge are only produced by the movement of electrons. THE CHARGES DO NOT MOVE. 

To discharge a charged conductor safely it needs to be connected to the earth via a metal strap. 

3) Like charges repel, opposite charges attract

Note: these forces get weaker the further apart the two things are. 

Nuisances of Static Electricity 

• Causes dust to be attracted. Dust particles carry a positive charge…