Science at key stage 3    (Year 9)

In this unit pupils:

• explore a range of useful energy transfers and transformations
• discuss the use of electricity as a convenient way to transfer energy to do useful things
• associate the concept of voltage with the transfer of energy in a circuit
• investigate the voltage of cells
• study how electricity is generated, with reference to environmental impacts
• use the principle of conservation of energy to identify ways in which energy is dissipated during transfers

In scientific enquiry pupils:

• use models to explain observations relating to electric currents
• use scientific knowledge to frame a question for investigation
• measure voltage in circuits
• identify patterns in the measurements of voltage in series circuits and use these to draw conclusions

This unit presents a range of useful changes and helps pupils to use the language of energy transfer and transformation in describing them. The word 'transfer' is used to describe energy's change of place; the word 'transform' is used to describe a change in the way energy shows itself, eg from electrical energy to light.

The unit focuses on how transfers and/or transformations of energy by electricity are important in everyday life. It explains these simply and looks at some of the consequences of the electricity supply industry. The unit covers the ideas of dissipation or 'wasted' energy and the conservation of energy. In extending the concept to these contexts, simplifications appropriate to year 9 pupils have been made.

Pupils need labels they can use when they come across energy, eg electrical energy, light and heat. This is a first step in developing understanding. Teachers should help pupils recognise that they need to go further in some contexts, eg that 'spring energy' is the result of the elastic properties of the metal the spring is made of, and so could be called 'potential energy' because of its compressed position. It would be inappropriate, at this stage, to develop this further and associate the energy with the electric bonding forces between the atoms of the spring. Formal definitions of work, kinetic energy and potential energy are also best left until key stage 4 for most pupils.

This unit is expected to take approximately 8 hours.