WARM UP

Have you ever had an electric shock when getting out of a car?

Lightning is a form of electricity

LEARNING OBJECTIVES

Students will be able

1.to recall that electric charges are seperated when certain materials are rubbed against one another ,that polythene becomes negatively charged and perspex becomes positively charged when rubbed with cloth

2.Explain charging of objects in terms of properties of objects which are free to move

Static Electricity

Static electricity occurs when charges build up on the surface of material.it is called static because the charges do not move

Why does a balloon , charged by rubbing, stick to the ceiling?.

The balloon on rubbing becomes negatively charged. The negative charge on the balloon repels some of the electrons in the wall away from the surface. This leaves the wall surface positively charged. Since opposite charges attract, the balloon gets attracted to the wall

CHARGING BY INDUCTION

FINAL ASSESSMENT1.What do you mean by static electricity?

2. Explain how polythene becomes negatively charged and perspex becomes positively charged when rubbed with cloth.

3.Explain charging by friction.

4.Write the three different ways of charging.

5.Why does a balloon , charged by rubbing, stick to the ceiling?

6.Explain charging by induction with the help of a diagram.