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KEY WORDS

KEY WORDS. RENEWABLE ENERGY CONSERVED DISSIPATED. USEFUL WASTED EFFICIENCY SANKEY. Tuesday, 12 June 2012. Forms of Energy. Learning Objectives: Recognise the different forms of energy How can we describe energy transfer Realise that energy cannot be created or destroyed.

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KEY WORDS

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  1. KEY WORDS • RENEWABLE • ENERGY • CONSERVED • DISSIPATED • USEFUL • WASTED • EFFICIENCY • SANKEY

  2. Tuesday, 12 June 2012 Forms of Energy • Learning Objectives: • Recognise the different forms of energy • How can we describe energy transfer • Realise that energy cannot be created or destroyed

  3. Energy Transfers Write down the energy transfers that happen in each appliance and label the useful and wasted energies. Toaster Crane Kettle Rocket Car engine Firework Speaker TV

  4. Energy cannot be created or destroyed

  5. Useful Energy and Efficiency You will be able to: • Recognise the different forms of useful energy. • Realise where the wasted energy goes to. • Draw an accurate Sankey diagram. • Calculate the efficiency of a device.

  6. Let the games begin You have to draw each shape below as accurately as possible.....

  7. Now swap books and harshly mark your partner’s work

  8. Sankey Diagrams These show the energy transfers in a device Useful energy out Energy in Cut out a shape, stick it in and copy the info from this slide down. Then go into the computer room and log onto my wiki. Wasted energy out

  9. Sankey Diagrams – A filament light bulb Light Electrical Energy Heat

  10. Sankey Diagrams – An LED Electrical Energy Light Heat LEDs are more efficient than traditional filament bulbs, because a greater percentage of the energy is transferred to light – rather than wasted as heat.

  11. Efficiency 80 J of useful light energy from 100 J of electrical energy. This would be 80% efficient Electrical Energy Light 80 J 100 J Heat 20 J

  12. Efficiency How much useful energy from 100 J of electrical energy? How efficient is this? ? J 4 J 4 % 100 J 17 J 79 J

  13. Efficiency How much useful energy from 894 J of energy input? How efficient is this? 60 J ? J 6.7% 894 J 103 J 731 J

  14. efficiency =useful energy out (x 100%) total energy in efficiency = useful power out (x 100%) total power in Wasted energy is eventually transferred to the surroundings, which become warmer. The wasted energy becomes increasingly spread out and so becomes less useful.

  15. Page 50: Take appropriate notes, then answer questions 1,2 and 3

  16. Page 50: Take appropriate notes, then answer questions 1,2 and 3

  17. How can we improve efficiency?

  18. Practicals • Filament/LED bulb set-up • Lego bricks • Candle/torch taped to board

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