4 Energy resources and energy transfers

Use the units kilogram (kg), joule (J), metre (m), metre per second (m/s), metre per second squared (m/s²), newton (N), second (s) and watt (W).

Describe energy transfers involving energy stores:

• energy stores: chemical, kinetic, gravitational, elastic, thermal, magnetic, electrostatic, nuclear
• energy transfers: mechanically, electrically, by heating, by radiation (light and sound)

Use the principle of conservation of energy

Know and use efficiency = useful energy output ÷ total energy output × 100%.

Describe a variety of everyday and scientific devices and situations, explaining the transfer of the input energy in terms of the above relationship, including their representation by Sankey diagrams

Describe how thermal energy transfer may take place by conduction, convection and radiation

Explain the role of convection in everyday phenomena

Explain how emission and absorption of radiation are related to surface and temperature

Practical: investigate thermal energy transfer by conduction, convection and radiation

Explain ways of reducing unwanted energy transfer, such as insulation

Know and use work done = force × distance moved in the force direction, W = Fd.

Know that work done is equal to energy transferred

Know and use gravitational potential energy = mass × gravitational field strength × height, GPE = mgh.

Know and use kinetic energy = ½ × mass × speed², KE = ½mv².

Understand how conservation of energy produces a link between gravitational potential energy, kinetic energy and work

Describe power as the rate of transfer of energy or the rate of doing work

Use power = work done (energy transferred) ÷ time taken, P = W/t.

Describe the energy transfers involved in generating electricity using:

• wind
• water
• geothermal resources
• solar heating systems
• solar cells
• fossil fuels
• nuclear power

Describe the advantages and disadvantages of methods of large-scale electricity production from various renewable and non-renewable resources