Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
P1a Energy & Energy Resources Ks4 Core Science Mr D Powell
2.1 Forms of energy • (U) Both wasted energy and the energy which is usefully transferred/ transformed are eventually transferred to their surroundings which become warmer. • (K) Energy cannot be created or destroyed. It can only be transformed from one form to another form.
Make a table listing the items in the diagram and link any energy changes you think apply; ELECTRIC TORCH PENDULUM Gravitational Potential Energy Chemical Potential Energy Elastic Potential Energy Heat (Thermal) Light Sound Kinetic Electrical CANDLE SPRING HiFi
chemical energy A. B. C. D. E. Energy Changes... • 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. • electrical energy • kinetic energy • gravitational potential energy • sound energy and thermal energy due to friction • thermal energy due to resistance of the wires Chemical Energy Electrical Energy Kinetic Energy Thermal wasted Sound Gravitational PE
chemical energy A. B. C. D. E. More Energy Changes... • A falling weight can be used to light a lamp using a winch and a generator. electrical energy kinetic energy gravitational potential energy light energy sound and thermal energy due to friction thermal energy due to resistance of the wires and lamp GPE Kinetic Electrical Thermal/ Sound wasted Thermal in wires wasted Light
Energy Transforms • Use the pictures on this page to inspire you to talk about the energy changes on rollercoaster's. • Write an article (with diagrams) designed for a magazine aimed at GCSE / Year 9 pupils who need to know about all the energy changes involved in the rollercoaster. Possible Key Words.... Kinetic, GPE, Friction, Thermal, Useful, Wasted, sound, velocity, acceleration...
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.
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....
Energy Transformations... Copy and complete the table below on the energy transformations....
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
Food Chains • growth • heat • locked into cells • growth • heat • kinetic • sound • excretion • growth • heat • kinetic • sound • excretion
Talking point... US Energy uses / wastage 2002 What can you say about energy use in the US in 2002?
Summary Questions • Energy can _________ from one form into other forms. • Energy can be ___________ from one place to another place. • Energy cannot be ________ or __________. • _______ or _______ energy is energy in the place we want it and in the form we need it. • _______ energy is energy that is not useful. • Useful energy and wasted energy both end up being transferred to the ____________ which become warmer. • As energy _______out, it gets more and more difficult to use for further energy transfers. transformed transferred created destroyed useful Stored wasted surroundings spreads
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
Which uses the lowest energy... Can you sort these into a rough order....
Which uses the lowest energy... Can you sort these into an order....
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....
Efficiency Calculations Can you work out the missing numbers for this table... Useful Energy Efficiency = Energy Supplied
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.
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.
Accurate Sankey Diagrams • 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 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.
Sankey Diagrams • This diagram represents energy transfer by the drill motor. The manufacturer claims the drill motor has an efficiency of 0.35. The drill motor is supplied with 3000 J of electrical energy when the hole is drilled. • What form of energy does A represent? • What does B represent and what forms of energy are included in it? • What is the useful energy transferred by the drill motor used for? • What is the useful energy from the drill motor? • What is the energy wasted by the drill? Electrical wasted thermal / sound Kinetic 0.35x 3000J = 1050J (1-0.35) x 3000J = 1950J
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....
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
Floor Insulation • 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
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
Cavity Wall Insulation This is a very modern form of cavity wall. The Glassroc is made from glass fibres matted together and prevents convection currents
Draught Excluders These brush like structures prevent convection currents around doors and are very cheap to fit. They also come in a rubber seal form to go around windows
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.