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9I Energy and electricity

By Patricia Robertson,2014-12-28 11:06
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9I Energy and electricity

Unit 9I Energy and electricity

    About the unit Where the unit fits in

    In this unit pupils: This unit builds on work on electricity and energy in units 7I ‘Energy resources’, 7J explore a range of useful energy transfers and transformations ‘Electrical circuits’ and 8I ‘Heating and cooling’. It relates to work on the reactivity of metals discuss the use of electricity as a convenient way to transfer energy to do useful things in unit 9F ‘Patterns of reactivity’ and work on fuels in unit 9G ‘Environmental chemistry’. It associate the concept of voltage with the transfer of energy in a circuit relates to unit 9D ‘Using control for electronic monitoring’ in the design and technology investigate the voltage of cells scheme of work, and to unit 18 ‘Twentieth-century conflicts’ and unit 20 ‘Twentieth-century

     study how electricity is generated, with reference to environmental impacts medicine’ in the history scheme of work.

     use the principle of conservation of energy to identify ways in which energy is dissipated

    during transfers Expectations In scientific enquiry pupils: At the end of this unit use models to explain observations relating to electric currents in terms of scientific enquiry use scientific knowledge to frame a question for investigation most pupils will: identify patterns in measurements of voltage and use these to draw measure voltage in circuits conclusions about circuits; identify and control key factors in investigating simple cells identify patterns in the measurements of voltage in series circuits and use these to draw and identify patterns in their results, including observations that do not fit the main trends conclusions some pupils will not have made so much progress and will: measure the voltage of a Note on the teaching of energy range of cells; present data as charts or tables

    This unit presents a range of useful changes and helps pupils to use the language of energy some pupils will have progressed further and will: relate energy transfer devices in the

    transfer and transformation in describing them. The word ‘transfer’ is used to describe laboratory to everyday appliances; synthesise information from secondary sources about

    the development of the electricity supply industry and communicate it clearly; consider energy’s change of place; the word ‘transform’ is used to describe a change in the way

    whether data is sufficient, and account for anomalies energy shows itself, eg from electrical energy to light.

    in terms of physical processes The unit focuses on how transfers and/or transformations of energy by electricity are

    most pupils will: describe some energy transfers and transformations in familiar situations, important in everyday life. It explains these simply and looks at some of the consequences

    including dissipated energy, and devices; recognise that the voltage change across a of the electricity supply industry. The unit covers the ideas of dissipation or ‘wasted’ energy circuit component is a measure of its energy transfer; describe how voltage originates and the conservation of energy. In extending the concept to these contexts, simplifications from a chemical cell; give examples of the hazards of high-voltage circuits; compare the appropriate to year 9 pupils have been made. energy consumption of common electrical appliances; describe how electricity is Pupils need labels they can use when they come across energy, eg electrical energy, light generated by energy from fuels, and recognise possible environmental effects of this and heat. This is a first step in developing understanding. Teachers should help pupils some pupils will not have made so much progress and will: describe some useful recognise that they need to go further in some contexts, eg that ‘spring energy’ is the result energy transfer devices; recognise that any functioning circuit needs a power supply to of the elastic properties of the metal the spring is made of, and so could be called ‘potential provide a voltage and that high voltages are hazardous; recognise that electricity is a energy’ because of its compressed position. It would be inappropriate, at this stage, to convenient way of ‘delivering’ energy, but that it must be paid for and that its generation develop this further and associate the energy with the electric bonding forces between the can cause environmental problems; give examples of how energy goes to waste atoms of the spring. Formal definitions of work, kinetic energy and potential energy are also some pupils will have progressed further and will: apply a model of voltage and energy best left until key stage 4 for most pupils. changes to a circuit; recognise that although the total energy in a system is conserved,

    energy can be dissipated; use ‘power ratings’ in comparing the costs of using different This unit is expected to take approximately 8 hours.

    electrical appliances; link the function of an electric generator to magnetic effects

     ? QCA 2000 Browse, save, edit or print Schemes of Work from the Standards Site at www.standards.dfee.gov.uk Science - Unit 9I Energy and electricity 1

    Prior learning Out-of-school learning It is helpful if pupils: Pupils could:

     know how to connect simple series and parallel circuits survey the power rating of various devices in the home or observe their electricity meter

     recall that fossil fuels and wind, waves and the Sun are all energy resources when different appliances are running

     check their own electricity bill

     keep a diary of energy experiences, eg Today I used my personal stereo with new Health and safety batteries Risk assessments are required for any hazardous activity. In this unit pupils: use mains electrical equipment in their investigations

    Pupils must not experiment with mains electricity.

    Model risk assessments used by most employers for normal science activities can be found in the publications listed in the Teacher’s guide. Teachers need to follow these as indicated

    in the guidance notes for the activities, and consider what modifications are needed for classroom situations.

    Language for learning

    Through the activities in this unit pupils will be able to understand, use and spell correctly: words and phrases relating to scientific enquiry, eg independent and dependent variable,

    control

     words and phrases describing energy transfers and transformations,

    eg movement as kinetic energy, position as potential energy, chemical energy, electrical energy, sound, heat and light

     words and phrases relating to energy supply and waste, eg conservation, dissipation,

    electric generator, dynamo, power station

    Through the activities pupils could:

     use secondary sources to assess conflicting evidence and arrive at a considered viewpoint

     write coherent text to communicate information effectively

    Resources

    Resources include:

     a selection of electrical toys and devices to show energy transfers and transformations samples of fruit and vegetables or dilute acid solutions

     a selection of samples of metals to make electrodes, eg copper, zinc, iron, aluminium,

    magnesium

     secondary source material on generating electricity and associated environmental issues, electric cars and other ‘energy-saving’ appliances

     small motors or materials to build generators

     a bicycle dynamo

     a joulemeter (and datalogger)

     ammeters and voltmeters or digital multimeters

     a household electricity meter or picture of one

     domestic appliances, including low-energy bulbs, or pictures of and energy information about these

     ? QCA 2000 Browse, save, edit or print Schemes of Work from the Standards Site at www.standards.dfee.gov.uk Science - Unit 9I Energy and electricity 2

LEARNING OBJECTIVES POSSIBLE TEACHING ACTIVITIES LEARNING OUTCOMES POINTS TO NOTE

    PUPILS SHOULD LEARN PUPILS

How is energy involved in doing useful things?

     that useful changes usually Remind pupils of their experience of energy transfers and transformations recognise that energy is The energy ‘transfers’ met in involve energy transfers and in years 7 and 8 with demonstrations of ‘useful changes’, eg working a routinely converted from one conduction in unit 8I ‘Heating and transformations model steam engine, a spring-driven clock, eating food. Help pupils form to another in order to cooling’ can be contrasted with that the terms ‘kinetic’, associate the presence of energy with the different situations in the be useful energy ‘transformations’ in these ‘potential’, ‘radiation’ and demonstrations, eg steam-engine fuel, flame, hot water, movement, and to categorise devices on the devices. Energy should, however, be ‘chemical’ are useful when use the terms ‘kinetic’, ‘potential’, ‘chemical energy’, ‘heat’, ‘light’ and basis of type of energy input associated with the situations rather describing energy ‘sound’ as ways of describing energy in such situations. or output than being described as different

     Ask pupils to explore a circus of toys and devices that work by transferring explain why electricity is ‘types of stuff’. See the note on

    and/or transforming energy. Ask pupils to identify the source of energy and used widely as a source of teaching energy in the Teacher’s the use to which it is put. Include a range of electrical toys and devices, eg energy guide. battery-operated and clockwork/spring-operated vehicles describe energy transfers in Potential energy is used to refer to yo-yo (if possible one that lights up at maximum speed) everyday changes energy associated with an object’s battery-operated and manually operated fans position, eg a stretched spring or a electromagnet for lifting raised mass. electric bell or buzzer

     solar-powered calculator or motor

     low-voltage heater that is set to get warm, not hot, to the touch

     toys that feature light-emitting diodes (LEDs)

     simple control circuit, eg one that sounds a buzzer when a light sensor

    is covered

     that electrical circuits are Elicit from pupils’ observations the conclusion that electrical energy is a describe the energy transfers used to perform a variety of convenient way to do many useful things. Recall pupils’ year 7 work on and/or transformations in

    useful tasks fuels as energy stores and elicit other ways that energy can be stored, eg several toys or devices

     that electrical energy is compressed spring potential; flywheel kinetic; battery chemical. recognise that electricity is a transferred around circuits Contrast this with electricity, which cannot be stored. useful means of

    and can be transformed in transforming energy

    components, eg to produce give examples of ways in

    light, sound, movement and which energy can be stored

    heat

     to identify devices and