2. • Energy:
Energy is the ability of an object to change things around it.
Energy can be mechanical, light, sound, thermal, electrical, chemical or nuclear.
Sources of energy
3. • Electricity
Electricity is a form of energy.
Electricity is transported through power lines Electricity is transformed into other types of
energy
Electrical charges
An object is neutral when it has the same number of positive and negative charges.
An object is positively charged when it has more positive than negative charges.
An object is negatively charged when it has more negative than positive charges.
Conducting and insulating materials materials.
Electrical charges move easily through conducting
Electrical charges cannot move through insulating materials.
4. • Electrical current:
Electrical current is the movement of electrical charges through a conducting material.
The elements in an electric circuit are:
1) The battery is the generator.
2) The wire is the conductor.
3) The light bulb is the receiver.
4) The switch open or close the
electric circuit.
5. • Producing electricity:
Electricity is produced in power stations:
Hydroelectric power stations Nuclear power stations
Thermal power stations Wind farms and solar power stations
6. Energy and the environment:
Changes in the landscape.
Depletion of non-renewable energy.
Pollution.
Using energy efficiently:
• Turn off the lights. • Use public transport.
• Turn off heaters and • Practise the 3 R s.
air conditioning.
7. • Magnetism
Magnetism is the ability of materials to attract metals such as iron and steel.
There are two types of magnets: natural and artificial.
Characteristics of magnets
Same poles repel each When we break a
Different poles attract magnet in half , we
each other. get two magnets
The magnetic poles of the Earth
8. • Uses of magnetism
Magnets are used in door locks, bags, electric motors and clocks.
Magnetism is used to store information on credit cards, mobile phones and
computer drives.
Electromagnetism
Electricity produces magnetism.
Magnetism produces electricity.
magnet
When the wheel turns, the magnet
inside the dynamo turns and it creates copper
an electrical current.
