The energy transferred in this picture is

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The energy transferred in this picture is.
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Learning objectives

• Describe the energy transfers in a range of
  devices.
• Identify where energy is wasted.
• Explain why wasted energy is difficult to use.

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Forms of energy
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Forms of energy

• Energy is needed to keep us working, and to
  operate all the machines around us.
• Different forms of energy include..
• Light, sound, electrical, potential and kinetic
  energy.
• Energy can also be stored. Nuclear energy is
  stored inside atoms. Food, fuels and electric
  batteries are stores of Chemical energy.
• Anything that is squashed, stretched or twisted
  stores Elastic potential energy.
• An object in a high position stores energy as
  Gravitational potential energy.

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Energy transfers

• Machines transfer energy between different forms.
  
• An mp3 player transfers stored chemical energy
  into electrical energy and sound energy.
• Sometimes more than one transfer is involved. The
  engine of a car transfers chemical energy in the
  petrol into kinetic energy (useful) and heat and
  sound (not useful and called wasted energy).

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• Click
• (select no option)

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Q) Label the useful and the wasted energy
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Conservation of energy

• Energy cannot be created or destroyed, it can
  only be transferred usefully, stored or wasted
  (called dissipated).
• THE TOTAL AMOUNT OF ENERGY DOES NOT CHANGE.
• This is called the principle of conservation of
  energy.

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Spreading out

• If you look at an energy transfer it can often
  seem as if some of the energy has disappeared.
• For example, a car uses chemical
• energy stored in its fuel.
• The fuel stores a lot of energy in a small space.
  This chemical energy is eventually transferred by
  heating into the surroundings, which become
  warmer. This dissipated energy is very difficult
  to use for further energy transfers.

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Questions

• What are the energy transfers of a torch?
• You are running in sports day. What forms of
  energy are you transferring that are A) useful
  and B) wasted?
• A car uses a litre of petrol when it is driven
  to the shops and back. What happens to the
  chemical energy that was stored in the petrol?

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• What are the forms of energy produced in a Bunsen
  burner?
• If energy cannot be destroyed, how can we waste
  energy?
• Draw a flow chart to show all the energy
  transfers in a wind-up torch, starting with food.
  Show how energy is wasted at each stage.