Natural science

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Natural sciencecompiled by Mondlane.J

Source of Energy

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Sun

Sun ,s energy long ago is also stored in wood, oil and coal. Materials, which store energy, are called fuels.

Sun energy gives us heat energy and light energy. The heat from the sun has travelled across space and through the atmosphere to warm us. We call this kind of energy sun's radiant energy is called solar energy.

We have learnt that energy from the sun warms and lights up earth.

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In what other ways do we use energy from the sun?

We can use the sun’s energy to dry washing.

We can use the energy to warm our homes.

We can use solar energy to make electricity.

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Other sources of energyWrite down where you think energy come from.

Example:Radio – energy comes from electricity supplied

by batteries.Fire- energy comes from burning coal or woodEnergy comes from different sources. Example:

coal, wood, oil, gas, steam, food, paraffin, electricity and so on.

What is fuel – its is substance that release energy when it is burned.

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Where do fuels come from?All energy comes originally from the sun. Green plants

absorb the energy from the sun.The plant use the sun's energy when produce food

energy. people and animals get food energy when they eat plants.

Most of the fluels come from the plants.Wood comes from trees that have been cut down. coal,

oil, petrol, and paraffin come from plants and animals that died and were compressed million of years ago. We call these fossil fuels.

Food is also fuel. When it is broken down in the body, the food release energy, which the body can use.

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Figure 6 source of energy

sun

Sun is renewable source of energy

because cannot used up.

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Activity 7

1. Name all sources of energy.2. Where do all of this energy come

from?

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Fossil fuels and synthetic fuelsFossil fuelsSome natural fuels are called fossil fuels.

Synthetics fuels are processed fuels. They can be made from:

fossil fuelsSome rocksSome types of soilSome chemicalsbiomass

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Different forms of fuel Solid fuels Coal is a hard, shiny, black rock. It is a solid fuel, which is used to

make electricity.

Liquid fuels Petroleum is a liquid fuel. Liquid fuels are the largest source of

energy for cars, trucks and aeroplanes.

Gas fuels Gas fuels travel easily through pipes.gas fuels are used to produce

energy for many homes and businesses all over the world.

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Activity 8

1. Name the three forms of fuel.

2. Give an example of each form of fuel and explain where each fuel can be used.

Activity 9

3. Write down what synthetic fuel are made from.

4. Which fossil fuels do you or your family use?

5. Give an example of each form of fuel explain where each fuel can be used.

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Energy from the sunThe sun’s energy is called solar

energy or solar power.The sun energy can be used to

heat up water. This kind of heating is not expensive. It can be used by the people in rural areas.

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Discuss solar energy1. Are these statements true or false? Copy the table in your exercise book

and tick the correct columns.

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Different forms of energy Chemical energy is energy stored in fuels like coal and oil and

batteries and food. chemical energy can also called food energy or stored energy.

Kinetic energy is the energy that something has when it moving. it is also called movement energy.

Heat energy is energy that something gives off when it get hot. Light energy is energy that something gives off it glows or burn. Sound energy is energy that something gives off it makes a noise. Electrical energy is energy that is made by an electric current.

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Different forms of energy

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Match the words in column A to the column B:

Column A Column B

1. Chemical energy

A. Energy given off when something is hot

2. Heat energy B. Movement energy

3. Kinetic energy

C. Energy given off when something glows or burn

4. Light energy D. Energy that is made by an electric current.

5. Electrical energy

E. Energy of noise

6. Sound energy

F. Energy stored in fuels and food