Date 4:Energy Diagrams Lesson Outcomes How I did Targets Task 1:Describe some energy transfer in appliances. Level 5 Task 2:Explain why transfer may not be 100%. Level 6 Task 3: Calculate running costs of an appliance over time. Level 7 Connector: (Level 4) Name the different forms of energy.

BIG picture What skills will you be developing this lesson? Numeracy Literacy Team work Self management Creative thinking Independent enquiry Participation Reflection How is this lesson relevant to every day life? (WRL/CIT)

What’s the energy transfer? Discuss the energy transfer involved in each appliance with the person next to you.

Energy transfer in electrical circuits 5 J transferred to bulb as light energy chemical energy from battery (e.g. 100J) heat energy of bulb 95 J transferred to 4

Energy transfer in electrical circuits Most of the energy from the battery does not produce light – most of it is wasted as heat! 5 J transferred to bulb as light energy chemical energy from battery (e.g. 100J) heat energy of bulb 95 J transferred to

Is all the energy useful to us? List the output energy as useful and wasted energy.

Discuss the energy transfer

Sankey diagram (Task 1) 15J 5J 35J 45J 100J

Draw the Sankey diagram (Task 1)

Task 1 (Level 5) Explain why energy transfer may not be 100%.

How can I improve on task 1? Task 1: Review Go back to your lesson outcome grid and fill out the ‘How I did’ and the ‘Targets’ column. Lesson Outcomes How I did Targets Task 1: Level 5 Met? Partly met? Not met? How can I improve on task 1?

Calculating energy efficiency total energy input useful energy output %Efficiency = x 100 This bulb converts 200 J of chemical energy from battery into 10 J of useful light energy: Efficiency of bulb = 10 200 = 5% x 100 ( )

New Information for Task 2 This radio converts 200 J of chemical energy from battery into 20 J of sound energy: Calculate the efficiency of the Radio. total energy input useful energy output %Efficiency = x 100

Task 2 This kettle converts 100 J of chemical energy from battery into 75 J of wasted sound and light energy. Calculate the efficiency of the kettle. total energy input useful energy output %Efficiency = x 100

New Information for Task 2 Calculate the efficiency of the fuel total energy input useful energy output %Efficiency = x 100

Calculate it’s efficiency (Task 2)

Questions

How can I improve on task 2? Task 2: Review Go back to your lesson outcome grid and fill out the ‘How I did’ and the ‘Targets’ column. Lesson Outcomes How I did Targets Task 2: Level 6 Met? Partly met? Not met? How can I improve on task 2?

Measuring electricity Electricity is measured in KWh, this is sometimes called a unit

Questions 1.5 kW 0.08 kW A Unit. Energy transferred = power x time = 2 kW x 3 h = 6 kWh

Cost of energy transfer How can we calculate the cost of energy transfer ?

Electrical cost

Questions 50 kWh 300 p or £3 The same: in both cases the number of kilowatt-hours is 12. 36 p 8.64 p @ 9 p

How can I improve on task 3? Task 3: Review Go back to your lesson outcome grid and fill out the ‘How I did’ and the ‘Targets’ column. Lesson Outcomes How I did Targets Task 3: Level 7 Met? Partly met? Not met? How can I improve on task 3?

Homework Homework task: Due date: Criteria for level 5:

Review of lesson