describe how energy in chemical stores in batteries, or in fuels at the power station, is transferred by an electric current, doing work on domestic devices, such as motors or heaters
describe how energy in chemical stores in batteries, or in fuels at the power station, is transferred by an electric current, doing work on domestic devices, such as motors or heaters
explain, with reference to examples, the relationship between the power ratings for domestic electrical appliances, the time for which they are in use and the changes in stored energy when they are in use
recall and apply the following equation in the context of energy transfers by electrical appliances:
energy transferred (J, kWh) = power (W, kW) × time (s, h)
describe, with examples, where there are energy transfers in a system, that there is no net change to the total energy of a closed system qualitative only
describe, with examples, system changes, where energy is dissipated, so that it is stored in less useful ways
explain ways of reducing unwanted energy transfer e.g. through lubrication, thermal insulation
describe the effects, on the rate of cooling of a building, of thickness and thermal conductivity of its walls qualitative only
recall and apply the equation: efficiency = useful energy transferred ÷ total energy transferred to calculate energy efficiency for any energy transfer, and **describe ways to increase efficiency **
interpret and construct Sankey diagrams to show understanding that energy is conserved