Static Electricity Chapter 50 What is electricity Electricity

Static Electricity Chapter 50

What is electricity? • Electricity is a form of energy and it may be converted to other forms. • It can cause a motor to turn and a kettle to heat up

Static Electricity. • Static electricity involves charges that remain at rest on an object. • When two objects are rubbed together, electrons get transferred from one object to the other. • Some substances like polythene and perspex (good insulators) do not allow these electrons to flow out so they build up an electrical charge called static electricity.

Polythene Rod • The polythene rod becomes negatively charged. • This is because electrons move from the cloth on to the polythene rod.

Perspex Rod. • If a perspex rod is rubbed with a woolen cloth The perspex rod becomes positively charged. • This is because electrons move from the rod on to the cloth. Perspex

Negative and positive charge • A body is negatively charged if it gains electrons. • A body is positively charged if it loses electrons. Note: Only the electrons can move

To investigate the force between charged objects. • Set up apparatus as shown in diagram. • Bring a charged polythene rod(-) close to but not touching a charged perspex(+) rod. • Result • The rods are attracted to each other. Like charges repel; Unlike charges attract.

What happens if the balloon on the left is let go? Explain your answer.

Effects of Static electricity • Van Der Graff generator • Hair raising moment

Useful effects of static electricity. Static electricity can be used in: • • Photocopier Spray painting Pesticides Removes soot from chimneys

Nuisance effects of static • Attract Dust • Electric shock from car Dangerous effects • Inflammable liquids can ignite causing fire • Thunder and lightning

Damage to a church caused by lightning

Earthing • Earthing occurs when a charged object loses it’s charge to the earth. • A lightning conductor protects buildings because it provides an easy route for the lightning to get to earth.