Conservation of Energy 13/11/2018 Objective To describe a wide range of energy transfers and explain the Principle of Conservation of Energy.

Different Forms of Energy kinetic energy thermal energy electrical energy magnetic energy elastic potential energy gravitational potential energy chemical potential energy Get pupils to discuss in groups of 2 or 3 what types of energy they think are present in each of the examples. They can write the forms of energy present in some of the examples on the Forms of Energy Worksheet Task 1. Discuss how the mass and the velocity of the object effects the kinetic energy. Discuss how gpe increses with mass and height above the ground.

Energy transfer in a television An energy transfer diagram shows the input energy and the output energies for a device. This includes all the useful and wasted forms of energy. For example, in a television: light sound electrical heat

Energy transfer in a radio What are the main energy transfers in a radio? (Don’t forget the wasted energy.) sound electrical heat

Energy transfer in a car engine What are the main energy transfers in a car engine? (Don’t forget the wasted energy.) kinetic chemical sound heat

Energy Transfers Energy is not created or destroyed, it is transferred from one form to another. What are the types of input and output energy in each of these examples: What is the useful and wasted output energy in each case? Talk through the lightbulb example if pupils are unsure how to start. Extension: Pupils can complete Forms of Energy Worksheet Task 2 & 3.

Energy Transfer Sankey diagrams can be used to show energy transfer. The example shows the energy transfer in an energy-saving lightbulb. It shows that 100J of electrical energy is converted to 75J of light energy and 25J of heat (thermal) energy. Discuss the fact that the width of the arrow represents the amount of energy and draw an example. Pupils should now be able to complete ss_th2_phys_term 4_l3_worksheet.

Homework Energy changes Q 1-3 Homework: ss_th2_phys_term 4_l3_sq_energy changes_q1-3

Plenary Write two sentences, describing the energy transfer in a rollercoaster. Use ideas about kinetic energy and gravitational potential energy in your answer. Draw a diagram if it helps.