Physics - Static Electricity

Build up of static is cuased friction. 

1. Two insultaing materials are rubbed together - electrons get scraped off one of them and put onto the other. Electrons are negatively charged.
2. This leaves a positive static charge on the material that had the electrons scraped off and a negative static charge on the other
3. The way the electrons get transferred depends on the two materials (polythene rod and cloth = electrons move from the cloth to the rod. Acetate rod and cloth = electrons move from the rod to the cloth). 

Static charge is only ever caused by the movement of electrons. PROTONS NEVER EVER MOVE. Remeber: charged atoms are called ions. 

LIKE charges REPEL, OPPOSITE charges ATTRACT. So, two things with opposite charges are attracted to each other whereas two things with the same charge, repel each other. 

Static electricity gets its name as it is the build up of charge between two negatively charged insulators that are trying to repel each other but can't move apart because the positions are fixed. 

Real life situtaions?
- Attracting dust. Dust particles are ridiculously lightweight and so they are easily attracted to charged objects. A lot of household objects are made from insulators - glass, wood - which means they attract a lot of dust. 
- Clinging clothes and crackles. Synthetic clothes are easily charged by being put into the tumble dryer or pulled over head…