Energy Transfer

Key Issues

Titles

Chapters

• Both wasted energy and the energy which is usefully transferred/transformed are eventually transferred to their surroundings which become warmer
• calculate costs and interpret data to do with energy saving in the home or workplace (including pay-back time)
• calculate the number of kWh units given the power in kW and the time in hours
• carry out simple calculations using the formula (given): power = energy / time to calculate power in watts (W)
• Conservation of energy
• construct and interpret energy changes shown as Sankey diagrams
• describe energy transfers involving the following forms of energy; chemical, heat, electrical, sound, light, magnetic, nuclear, kinetic and potential (gravitational and strain)
• describe how domestic electricity is generated at a power station
• describe how energy is transferred by conduction, convection, radiation
• describe how the National Grid of powerlines connects power stations to consumers
• describe methods of insulation used in the home or work place
• Double Glazing and Insulation
• Efficiency is the proportion of energy transferred to useful work
• Energy becomes increasingly spread out and becomes increasingly more difficult to use for further energy transformations
• Energy cannot be created or destroyed. It can only be transformed from one form to another form
• Energy Efficiency
• Energy transfer chains in generating electricity
• Energy transferred = work done
• Energy transfers involving different forms of energy
• Energy which is not transferred/transformed in a useful way is 'wasted'
• evaluate data on different types of lighting systems to compare their efficiencies
• evaluate the suitability of different energy resources for a particular job in the home or workplace (natural gas, bottled gas, mains electricity, batteries, solid fuel, petrol/diesel, fuel oil)
• explain energy saving strategies in the context of the home or workplace
• explain that a car radiator and a refrigerator are examples of heat exchangers
• explain that in any process of energy transfer energy is conserved
• explain the advantages and disadvantages of electricity compared with other methods of supplying energy to the home
• explain the term insulation
• explain why electricity is an important way of supplying energy to the home
• Flow of Heat
• GENERATION OF ELECTRICITY
• Gravitational potential energy = mass x g x height
• Insulation materials which use trapped air
• Insulation to reduce energy transfer
• interpret energy changes shown as simple Sankey diagrams
• recall and use the formula: power = voltage x current
• recall and use the quantitative relationships for kinetic energy 1/2 mv2), gravitational potential energy (mgh) and power, in the context of the conservation of energy
• recall methods of insulation used: loft, cavity wall, double glazing; lagging
• recall that efficiency is a measure of how much energy is transferred in an intended way and calculate as the ratio of useful output energy to input energy
• recall that efficient energy sources transfer most of the energy from one form to another with little loss to the surroundings
• recall that inefficient energy sources transfer little of the energy from one form to another with much lost to the surroundings
• recognise and use given information on electrical appliances
• recognise examples of energy saving methods in the home or workplace
• recognise that some electrical appliances are more expensive to use than others
• recognise that there is a significant energy waste in the production of electricity at a conventional power station
• recognise that when energy is wasted it becomes spread out and is hard to reuse
• recognise the term insulation
• state and use the relationship for energy or power: % efficiency = useful energy output/total energy input x 100%
• state that a car radiator and a refrigerator are examples of heat exchangers
• state that a heat exchanger enables waste energy to be captured and recycled
• state that owners of homes and workplaces seek to reduce wastage of energy to reduce cost
• state the relative expense of different appliances given power ratings
• take readings from a domestic electricity meter
• The benefits of low energy appliances
• The Efficiency of a Device
• The fate of input energy
• The greater the percentage of the energy that is usefully transformed in a device, the more efficient the device is
• Transforming Energy
• understand that energy is conserved and describe energy changes in terms of the principle of conservation of energy
• understand that energy may be dissipated and become less useful and appreciate the role that friction plays in this
• use a comparison of low energy lamps and filament lamps to illustrate the advantages to the user and society of devices with high efficiency
• use a particle model to explain how energy spreads out
• use simple data to show that a low energy lamp is more efficient than a filament lamp
• use the term energy efficiency
• use the term heat exchanger as a device that captures and recycles energy
• Useful Transfer of Energy
• Uses of insulation
• Wasted Energy
• When energy is transferred and/or transformed only part of it may be usefully transferred/transformed
• Work = force x distance
• Work done = useful energy transferred