Mr Powell 2008 Index Using Energy

Mr Powell 2008 Index 2.1 Forms of energy  Both wasted energy and the energy which is usefully transferred/ transformed are eventually transferred to their surroundings which become warmer.  Energy cannot be created or destroyed. It can only be transferred from one store to another.  Both wasted energy and the energy which is usefully transferred/ transformed are eventually transferred to their surroundings which become warmer.  Energy cannot be created or destroyed. It can only be transferred from one store to another.

Mr Powell 2008 Index Make a table listing the items in the diagram and link any energy changes you think apply; PENDULUM ELECTRIC TORCH SPRING HiFi CANDLE PendulumKinetic -> GPE-> Kinetic TorchElectrical -> Heat -> Light.... Gravitational Potential Energy Chemical Potential Energy Elastic Potential Energy Heat (Thermal) Light Sound Kinetic Electrical Gravitational Potential Energy Chemical Potential Energy Elastic Potential Energy Heat (Thermal) Light Sound Kinetic Electrical

Mr Powell 2008 Index Energy Changes... chemical energy C. E. D. B. A. 1.electrical energy 2.kinetic energy 3.gravitational potential energy 4.sound energy and thermal energy due to friction 5.thermal energy due to resistance of the wires 1.electrical energy 2.kinetic energy 3.gravitational potential energy 4.sound energy and thermal energy due to friction 5.thermal energy due to resistance of the wires  A weight is raised using a winch driven by an electric motor. Use the forms of energy listed below to complete the energy flow diagram (wasted energy) (wasted energy) &4. 5&6.

Mr Powell 2008 Index More Energy Changes... chemical energy C. E. D. B. A. 1.electrical energy 2.kinetic energy 3.gravitational potential energy 4.light energy 5.sound and thermal energy due to friction 6.thermal energy due to resistance of the wires and lamp 1.electrical energy 2.kinetic energy 3.gravitational potential energy 4.light energy 5.sound and thermal energy due to friction 6.thermal energy due to resistance of the wires and lamp  A falling weight can be used to light a lamp using a winch and a generator &4 5&6.

Mr Powell 2008 Index 2.2 Conservation of energy  (K) Energy cannot be created or destroyed. It can only be transformed from one form to another form.  (K) When energy is transferred / transformed only part of it may be usefully transferred/ transformed.  (K) Energy which is not transferred/transformed in a useful way is wasted.  (U) Energy becomes increasingly spread out and becomes increasingly more difficult to use for further energy transformations.  (K) Energy cannot be created or destroyed. It can only be transformed from one form to another form.  (K) When energy is transferred / transformed only part of it may be usefully transferred/ transformed.  (K) Energy which is not transferred/transformed in a useful way is wasted.  (U) Energy becomes increasingly spread out and becomes increasingly more difficult to use for further energy transformations.

Mr Powell 2008 Index Get thinking? “tonight an in-depth look at what each of us can do to help conserve electricity” Where has the energy gone? What happens here....

Mr Powell 2008 Index DeviceInitial energyUseful energyWaste energy Portable radiochemicalsoundthermal Food mixerelectricalkineticthermal Hairdryerelectricalkinetic/ heatsound Gas firechemicalthermalLight Fridgeelectricalthermal Table lampelectricallightheat Energy Transformations... DeviceInitial energyUseful energyWaste energy Portable radiochemical energysound energy Food mixerelectrical energy Hairdryer Gas fire Fridge Table lamp Copy and complete the table below on the energy transformations....

Mr Powell 2008 Index Food Chains  A good example of energy which is lost to the surroundings is a food chain.  Use this graphic and your own ideas to present this with examples of real food chains. Explain clearly where the energy goes

Mr Powell 2008 Index Food Chains  growth  heat  locked into cells  growth  heat  kinetic  sound  excretion  growth  heat  kinetic  sound  excretion

Mr Powell 2008 Index US Energy uses / wastage 2002 Talking point... What can you say about energy use in the US in 2002?

Mr Powell 2008 Index Summary Questions 1.Energy can _________ from one form into other forms. 2.Energy can be ___________ from one place to another place. 3.Energy cannot be ________ or __________. 4._______ or _______ energy is energy in the place we want it and in the form we need it. 5. _______ energy is energy that is not useful. 6.Useful energy and wasted energy both end up being transferred to the ____________ which become warmer. 7.As energy _______ out, it gets more and more difficult to use for further energy transfers. transformed transferred created destroyed Stored wasted surroundings spreads useful

Mr Powell 2008 Index 2.3 Useful energy / 2.4 Energy and efficiency and efficiency issues  (S) To describe the energy transfers/transformations and the main energy wastages that occur with a range of devices to calculate the efficiency of a device.  (U) The greater the percentage of the energy that is usefully transformed in a device, the more efficient the device is.  (S) To evaluate the effectiveness and cost effectiveness of methods used to reduce energy consumption. i.e. Insulation  (S) To describe the energy transfers/transformations and the main energy wastages that occur with a range of devices to calculate the efficiency of a device.  (U) The greater the percentage of the energy that is usefully transformed in a device, the more efficient the device is.  (S) To evaluate the effectiveness and cost effectiveness of methods used to reduce energy consumption. i.e. Insulation

Mr Powell 2008 Index Which uses the lowest energy... Can you sort these into a rough order....

Mr Powell 2008 Index Which uses the lowest energy... Can you sort these into an order....

Mr Powell 2008 Index How much energy do appliances use.... Make a note of some of these appliances and their energy uses. Write a short sentence to explain why they might be Power hungry....

Mr Powell 2008 Index Device Energy supplied (in joules) Useful energy (in joules) Waste energy (in joules) Efficiency Electric motor Desk lamp PC monitor Microwave oven Torch lamp Device Energy supplied (in joules) Useful energy (in joules) Waste energy (in joules) Efficiency Electric motor Desk lamp PC monitor Microwave oven ,00010, Torch lamp Efficiency Calculations Can you work out the missing numbers for this table... Efficiency = Useful Energy Energy Supplied

Mr Powell 2008 Index Sankey Diagrams Sankey diagrams summarise all the energy transfers taking place in a process. The thicker the line or arrow, the greater the amount of energy involved. The Sankey diagram for an electric lamp below shows that most of the electrical energy is transferred as heat rather than light.

Mr Powell 2008 Index Efficiency?  How do the sankey diagrams show which light bulb is more efficient? Describe two devices and diagrams which explain this point. Ordinary electric lamps contain a thin metal filament that glows when electricity passes through it. However, most of the electrical energy is transferred as heat energy instead of light energy. Modern energy-saving lamps work in a different way. They transfer a greater proportion of electrical energy as light energy.

Mr Powell 2008 Index Accurate Sankey Diagrams Notice how this diagram is completed to scale. The vertical part of the scale is 2 squares = 10J of energy. Try and draw these 4 in a similar way on one sheet of graph paper. Torch with Chemical -> Light 5J & Heat 95J Car with Chemical - > Kinetic 25J & Heat 75J Bunsen Burner with Chemical -> Heat 85J, Light 10J, Sound 5J Hairdryer -> Electrical -> Sound 5J, Heat 20J, Kinetic 75J

Mr Powell 2008 Index Sankey Diagrams  This diagram represents energy transfer by the drill motor. The manufacturer claims the drill motor has an efficiency of The drill motor is supplied with 3000 J of electrical energy when the hole is drilled. 1.What form of energy does A represent? 2.What does B represent and what forms of energy are included in it? 3.What is the useful energy transferred by the drill motor used for? 4.What is the useful energy from the drill motor? 5.What is the energy wasted by the drill? 1.Electrical 2.wasted thermal / sound 3.Kinetic x 3000J = 1050J 5.(1-0.35) x 3000J = 1950J 1.Electrical 2.wasted thermal / sound 3.Kinetic x 3000J = 1050J 5.(1-0.35) x 3000J = 1950J

Mr Powell 2008 Index Preventing Energy Transfers...  For each of the following transfers on the following slides i.e. Loft insulation...  Write a sentence for each one to describe the transfers and how they are slowed down....

Mr Powell 2008 Index Insulation  We can insulate our homes to keep the energy in.  Different forms of insulation save us different amounts of money as they save different amounts of energy

Mr Powell 2008 Index This is usually used when installing an under floor heating system. This consists of;  carpet, ceramic tile, etc)  screed  water pipe  floor insulation  concrete sub-floor Floor Insulation

Mr Powell 2008 Index Cavity Wall Insulation II This insulation is in the form of polystyrene beads. This allows the house to breathe more freely than with the Glassroc

Mr Powell 2008 Index This is a very modern form of cavity wall. The Glassroc is made from glass fibres matted together and prevents convection currents Cavity Wall Insulation

Mr Powell 2008 Index These brush like structures prevent convection currents around doors and are very cheap to fit. Draught Excluders They also come in a rubber seal form to go around windows

Mr Powell 2008 Index Double Glazing Two glass sheets of glass create a sandwich of trapped air. This prevents conduction and convection currents. Often one surface has a special coating to absorb the suns infra red rays.

 A weight is raised using a winch driven by an electric motor. Use the forms of energy listed below to complete the energy flow diagram. 1.electrical energy 2.kinetic energy 3.gravitational potential energy 4.light energy 5.sound and thermal energy due to friction 6.thermal energy due to resistance of the wires /lamp 1.electrical energy 2.kinetic energy 3.gravitational potential energy 4.light energy 5.sound and thermal energy due to friction 6.thermal energy due to resistance of the wires /lamp  A falling weight can be used to light a lamp using a winch and a generator.