OCR P4 Science (Higher)

Charge-An Imbalance of electrons

Static electricity is the movement of electrons from one material to another, for example; When an acetate is rubbed with a duster, electrons are tranferred from the rod to the duster leaving the rod positively charged and the duster negativly charged.

Postive charge- Lack of electrons

Negative charge- Excess of Electrons

Static Electricity

Static electricty is not usually dangerous but more of an annoyance:

-Dust and dirt are attracted to insulators (such as the telly, this also explains why dusters work, because the dust is attracted to the cloth) and clothes made from man-made materials ofter cling to the body or each other.

Static electricity can, however, be dangerous in some situations;

• Static electricity in the pit (formula 1 racing)- Charge built up by the car during the race could set any fuel leaks on fire, or hurt someone changing the tyres.
• Oil Rigs- Static electricity from clothes could set light to the crude oil

Electric shocks can be avoided by;

• Having a earth wire, any object that could build up charge is connected to earth so that any possible build up is immediately discharged away safely.

• In factories, the operator of any machinery that could build up charge stands on rubber mats so that the machine does not discharge through them.

Anti-Static sprays, cloth and liquids are made from a conductding material to carry away charge.

Static electricity is used in a variety of different ways in everyday life;

Defibrillators

These are used to restore heart rhythm by delivering an electric shock through the Chest-Wall to the heart.