Summary AQA GCSE Physics Combined Science - Energy Notes

ENERGY

ENERGY RESOURCES
 ENERGY SOURCES
o Non-renewable:
 Fossil fuels (coal, oil, gas)
 Nuclear
o Renewable: energy that can be replenished as it is used
 Biofuel
 Wind
 Hydroelectricity
 Geothermal
 Tidal
 Solar
 RENEWABLE AND NON-RENEWABLE ENERGY
o Renewable energy is not always reliable
 Solar energy doesn’t work in bad weather or at night
 Wind is not always there
o Fossil fuels release harmful emissions and will eventually run out
o Wind turbines can be considered an eyesore




ENERGY TRANSFERS
 Energy can be transferred usefully, stored or dissipated but cannot be created or destroyed
 REDUCING ENERGY WASTE
o Lubrication (oil in a motor): reduces friction so less energy is lost as heat
o Thermal insulation (double glazing): less useful thermal energy lost
 EFFICIENCY
o The efficiency of a system can be increased by reducing waste output or recycling
waste output
o Efficiency = useful energy output/total energy input




POWER
 Power is the rate at which energy is transferred or the rate at which work is done
 Power = energy transferred/time or work done/time