describe the main energy sources available for use on Earth, compare the ways in which they are used and distinguish between renewable and non-renewable sources
fossil fuels, nuclear fuel, biofuel, wind, hydroelectricity, tides and the Sun
describe the main energy sources available for use on Earth, compare the ways in which they are used and distinguish between renewable and non-renewable sources
fossil fuels, nuclear fuel, biofuel, wind, hydroelectricity, tides and the Sun
explain patterns and trends in the use of energy resources
the changing use of different resources over time
recall that, in the national grid, electrical power is transferred at high voltages from power stations, and then transferred at lower voltages in each locality for domestic use
recall that step-up and step-down transformers are used to change the potential difference as power is transferred from power stations
explain how the national grid is an efficient way to transfer energy
link the potential differences and numbers of turns of a transformer to the power transfer involved; relate this to the advantages of power transmission at high voltages
recall that the domestic supply in the UK is a.c. at 50 Hz and about 230 volts
explain the difference between direct and alternating voltage
recall the differences in function between the live, neutral and earth mains wires, and the potential differences between these wires
explain that a live wire may be dangerous even when a switch in a mains circuit is open, and explain the dangers of providing any connection between the live wire and earth
the protection offered by insulation of devices