1. Lesson 2 – Teacher plan – your house 2minutes – funky LEDs video play next slide without sound as students enter. Ask what they know about LEDs. Introduce today’s topic and learning objectives 5 minutes – video How are LEDs can save the world 5 minutes – Discussion on light bulbs Gather students round and show filament, energy saving and LED light bulbs and why we prefer newer type. Try and draw out efficiency. 10- minutes – efficiency explanation use powerpoint to explain what is efficiency and how to calculate for high ability, 30 minutes – Read and do questions OR do experiment I’m not sure if the experiment is possible with our equipment but the next person reading this may know. 5 minutes – extension – how many sensors have you got in or around your home?

4. Learning Objectives Describe what is meant by efficiency Describe how an LDR and LED work Calculate efficiency and suggest ways to use an LDR Keywords Efficient Light emitting diode LED Light dependent resistor LDR Sensor Sensing circuit

5. Energy and Efficiency Be able to list the types of energy Be able to describe energy changes in machines Be able to calculate efficiency

6. Types of energy Most Kids Hate Learning GCSE Energy Names MagneticKinetic HeatLight Gravitational potential Chemical Sound Electrical Elastic potential Nuclear

7. Energy transfer Energy transfer diagrams show the locations of energy stores and energy transfers.

9. electrical light heat Efficiency in light bulbs electrical light heat 100J 10J 90J 40J 60J Notice it’s the same energy transfer…but a different amount of useful energy!

10. The Efficiency Equation Efficiency = Useful energy transferred ÷ Total energy supplied This can also be written as: Efficiency = Useful energy transferred Total energy supplied E.g. a plant takes 100J of light energy and from that stores 30J of chemical energy. Efficiency = Useful energy Total energy supplied Efficiency = 30J 100J Efficiency = 0.33ALWAYS A DECIMAL, unless you x 100 to get a percentage.

11. Which light bulb is most efficient? Light bulbElectrical energy in (J) Useful energy out (J) Wasted energy out (J) A301020 B401525 C5025

12. A house of the future could have circuits to detect if you are out, if it is daytime, and if the light is on – and then turn it off! How many things can you think of that use sensors in or around your house? Are any of them LED or LDRs?

13. Learning Objectives Describe what is meant by efficiency Describe how an LDR and LED work Calculate efficiency and suggest ways to use an LDR Keywords Efficient Light emitting diode LED Light dependent resistor LDR Sensor Sensing circuit