4bEnergy transfers

Syllabus objectives

• 4.2describe 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)
• 4.3use the principle of conservation of energy
• 4.4know and use the relationship between efficiency, useful energy output and total energy output: useful energy outputefficiency ×100%total energy output=
• 4.5describe 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
• 4.6describe how thermal energy transfer may take place by conduction, convection and radiation
• 4.7explain the role of convection in everyday phenomena
• 4.8explain how emission and absorption of radiation are related to surface and temperature
• 4.9practical: investigate thermal energy transfer by conduction, convection and radiationPractical
• 4.10explain ways of reducing unwanted energy transfer, such as insulation