1. Light and electricity

2. What is Energy?
 It is the ability to do work. It moves vehicles, lights and
heats our home and even makes our bodies grow.

3. Forms of Energy:
 Light
 Sound
 Heat
 Electricity

4. Renewable energy sources
 Solar energy (sun)
 Wind energy
 Geothermal energy
 Biomass (plants)
 Hydropower (water)

5. Non-renewable sources
 Petrol
 Coal
 Oil
 Natural gas
 Nuclear

6. Some types of energy:
 Solar Power  Chemical energy

7. Light
 This is an energy called electromagnetic radiation.
 When light passes through a prism, it separates into a
spectrum of colours called a rainbow.

8. Light Properties
 Reflection  Refraction

9. Tools to control and detect light
 Telescope
 Microscope
 Binoculars
 Cameras

10. Energy and electricity
 Oil, gas and coal are PRIMARY sources of energy.
Electricity is a SECONDARY source of energy.
 We transform other sources of energy to make
electricity. Electricity is transformed in power plants.

11. Matter
 Matter is made of atoms. Atoms are made of
electrons, protons and neutrons.
 When electrons move along wires, electricity is
produced.

12. Conductors
 Materials that allow electricity to flow, like metals, are
called CONDUCTORS.

13. Insulators
 Materials that don’t allow electricity to pass, like
rubber and plastic, are called INSULATORS.

14. Using energy
 Energy cannot be created or destroyed, but it can be
transformed into other types of energy:
- Batteries into light energy.
- Electrical energy on phone into sound energy.

15. Uses of Energy
 Industry: heat for steam or hot water, factories for
cooking, drying etc.
 Transportation: gasoline, diesel, electricity, gas, etc. for
vehicles.
 Public and residential use: electricity and gas for
heating and lighting in offices, hospitals, schools and
homes.

16. Clean energy
 Non-renewable sources of energy like coal, oil and
natural gas cause air pollution.
 Renewable energy like sunlight, wind or water is good.
 It replaces itself and doesn’t cause pollution.