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Natural science


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Natural science

  1. 1. Natural sciencecompiled by Mondlane.JSource of Energy 3/13/2013 1
  2. 2. 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 suns radiant energy is called solar energy. We have learnt that energy from the sun warms and lights up earth. 3/13/2013 2
  3. 3. 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. 3/13/2013 3
  4. 4. Other sources of energy Write down where you think energy come from. Example: Radio – energy comes from electricity supplied by batteries. Fire- energy comes from burning coal or wood Energy comes from different sources. Example: coal, wood, oil, gas, steam, food, paraffin, electr icity and so on. What is fuel – its is substance that release energy when it is burned. 3/13/2013 4
  5. 5. Where do fuels come from? All energy comes originally from the sun. Green plants absorb the energy from the sun. The plant use the suns 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. 3/13/2013 5
  6. 6. Figure 6 source of energy Fossil Source of sun trees fuels energy Sun is renewable Bread source of energy Trees can be because cannot renewable if we are Honey petrol careful. used up. Sugar wood If we cut down a coal whole forest , it will not grow again. All are called non- But if we cut only a renewable source of few trees , then the energy because the forest can renew y can used up itself. 3/13/2013 6
  7. 7. Activity 71. Name all sources of energy.2. Where do all of this energy come from? 3/13/2013 7
  8. 8. Fossil fuels and syntheticfuels Fossil fuels Some natural fuels are called fossil fuels.Synthetics fuels are processed fuels. They can be made from: fossil fuels Some rocks Some types of soil Some chemicals biomass 3/13/2013 8
  9. 9. 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. 3/13/2013 9
  10. 10. Activity 81. Name the three forms of fuel.2. Give an example of each form of fuel and explain where each fuel can be used. Activity 91. Write down what synthetic fuel are made from.2. Which fossil fuels do you or your family use?3. Give an example of each form of fuel explain where each fuel can be used. 3/13/2013 10
  11. 11. Energy from the sun The 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. 3/13/2013 11
  12. 12. Discuss solar energy1. Are these statements true or false? Copy the table in your exercise book and tick the correct columns. 3/13/2013 12
  13. 13. 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. 3/13/2013 13
  14. 14. Different forms of energy 3/13/2013 14
  15. 15. Match the words in column A tothe column B:Column A Column B1. Chemical A. Energy given off when something is hotenergy2. Heat energy B. Movement energy3. Kinetic energy C. Energy given off when something glows or burn4. Light energy D. Energy that is made by an electric current.5. Electrical E. Energy of noiseenergy6. Sound energy F. Energy stored in fuels and food 3/13/2013 15