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# S3 ENERGY

S3 ENERGY. Measuring Motion - Learning Intentions Lesson 1,2 - Heat losses in our homes. Revise the three processes of the transfer of heat energy. Raise awareness of the impact of these processes on their everyday lives. Be aware of different ways of insulating a house.

## S3 ENERGY

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1. S3 ENERGY

2. Measuring Motion - Learning IntentionsLesson 1,2 - Heat losses in our homes • Revise the three processes of the transfer of heat energy. • Raise awareness of the impact of these processes on their everyday lives. • Be aware of different ways of insulating a house. • Know that some methods of insulating are more effective than others. • Realise that wasting energy also means wasting money. • Realise that wasting energy contributes to global warming.

3. Revision Quiz – Qwizdom - Heat How much can you remember of the HEAT unit from S2?? Let’s find out as you take part in the HEAT Qwizdom quiz!!

4. Revision – Heat and Temperature • Heat is a type of energy and is therefore measured in Joules (J). • Temperature is a measure of how much heat energy an object has. It is measured in degree Celsius (°C). • Heat energy will always travel from a higher temperature material to a lower temperature material.

5. Revision - Heat Transfer • Conduction Conduction is when heat energy travels along a solid. Metals are the best conductors of heat. • Convection Convection is when a gas or liquid is heated and rises, drawing colder air in underneath it. This causes the air to circulate and transfer heat energy. • Radiation Objects give out energy as infrared radiation. Very hot objects glow red or even white hot. IR radiation does not need a material to travel through.

6. Where is heat lost from our homes? Can we now use the knowledge gained in S2 to answer this important question? BBC Class Clip: Grants to improve home insulation Use the internet with the ENERGY HOUSE WORKSHEET to RUN the Two Houses simulation. Complete the worksheet to study important facts about how heat is lost from our homes and how we can save energy - and money!

7. Measuring Motion - Learning IntentionsLesson 3,4 - Cutting down Heat Loss • Investigate how to cut down heat loss using a range of methods and materials • Be able to choose the most efficient insulating methods.

8. Challenge!! • There has been some controversy in the media recently with stories claiming that “Builders have been conning people out of money by wrongly advising them that installing home insulation cuts down energy loss” • You have been asked by your local council to come up with conclusive evidence to find if cavity wall insulation actually does save energy.

9. You will be allocated to a group. Each group has a specific practical to carry out that is shown in detail on the worksheet. Plot a graph of your results and present your findings to the class. Draw your own conclusions. Which was the best at retaining heat? Here are the options Were the media correct or does home insulation reduce heat loss?

10. Originally houses were built with a single wall. However, this was not a very good method of retaining heat so instead a second wall was introduced creating a cavity. This cavity is now filled with some insulating foam that contains air pockets which reduces heat loss by conduction and convection. The new method saves both heat energy and money. cavity conduction water energy pockets money convection single foam Cavity wall insulation single cavity foam pockets conduction convection energy money

11. Measuring Motion - Learning IntentionsLesson 5,6 – Home energy efficiency • Make predictions about which appliances in the home will use the most energy. • Understand that when we talk about ‘power’ we mean energy used each second. • Investigate and/or find out about power ratings (and therefore energy use) of a range of household appliances, using careful measurement and/or identifying appropriate sources of information. • Discuss and evaluate the results of the investigation.

12. Which appliances use most energy? • Look at the home appliances positioned around the room. • Make an ordered list of the appliances – with the high energy users at the top. • To check if your order is correct you will do will do a simple experiment using a mains energy monitor

13. Energy and Power • The energy a device uses is measured in Joules (J). • The amount of energy a device uses every second is called its “power”, measured in watts (W) or kilowatts (kW) • 1kW = 1000W

14. Which appliancesuse most energy? • Attach each appliance available in class to an energy monitor and press “Function” to set it to “Watt”. This shows the power (energy in 1 s). • Record the power for each appliance in a table: • Discuss how the order compares with your first list.

15. How to calculate the energy used by appliances • Measuring energy used in the home in joules (J) gives very large numbers. • Instead the energy used by electric appliances is measured in a unit of ‘kilo-Watt-hours’ (kWh) • You can work out the energy used in KWh you must know 2 things: • the appliance’s power in Watts or kilowatts from its wattage plate, • the number of hours the appliance is used • Now multiply these to find energy in kWh • Kilowatt-hours = kilowatts x hours

16. Example problems on the kWh • An electric fire has a power rating of 2000W. If it is on for 4 hours how many kWh of energy does it use? • kWh = kW x h, kWh = 2000 x 4 1000 kWh = 2 x 4 = 8 kWh • A microwave oven is rated at 800W. How many kWh of energy does it use to heat a meal if it on for 6 min? • kWh = kW x h, kWh = 800 x 6 1000 60 kWh = 0.8 x 0.6 = 0.48 kWh

17. Practice problems on the kWh • Remember : kWh = kW x h • How many kWh of energy is used by a heater with a power rating of 3kW. If it is used for 5h. • A 2kW toaster cooks toast in 3 minutes. How many kWh does it use? • A 500W TV is on for 6h. How many kWh? • A 60W electric fan is used for 20 min. How many kWh does it use? • A 600W microwave takes 2 minutes to heat chips. How many kWh does it use.

18. Answer to problems on the kWh • kWh = kW x h, kWh = 3 x 5 = 15 kWh • kWh = kW x h, kWh = 2 x 3_ 60 = 0.1 kWh • kWh = kW x h, kWh = 500 x 6 1000 = 3 kWh • kWh = kW x h, kWh = 60 x 20 1000 60 = 0.02 kWh • kWh = kW x h, • kWh = 600 x 2_ • 1000 60 = 0.02 kWh

19. Paying for electricity • The electricity companies charge their users for each kWh of energy they use. This is called the TARIFF Cost = kWh x tariff • E.g the tariff may be 10p/kWh (each kWh costs 10p) Q. How much would it cost to run a 2kW heater for 3h? A. Cost = kWh x tariff = 2 x 3 x 10 = 60p • Find how much it cost for the kWh you used in 1 day. • Calculate the cost of the appliances in the kWh questions Home energy calculator

20. Home Energy Audit • Follow the instructions given on the “Home Energy Audit” workcard. • Present your findings on an A4 sheet of paper.

21. Measuring Motion - Learning IntentionsLesson 7,8 - Energy in the future • Know about the need for clean, affordable, plentiful and reliable energy now and in the future. • Review the uses of energy and the need for reliable energy supplies. • Understand different energy changes. • Review energy generation from renewable and non-renewable sources, including biomass. • Discuss the impacts of humans on the environment.

22. What are the sources for these? What is energy used for ? • Heating • Cooking • Electricity for homes and factories • Transport • Gas , Oil, Electricity • Gas, Electricity • Electricity – coal, oil gas, nuclear, renewables • Petrol, diesel, kerosene

23. UK Energy Sources - 2011 • How will we get our energy • in the future? • What happens as fossil • fuel prices go up? • How can we reduce the amount of carbon dioxide we put into the atmosphere?

24. What are the best energy sources for the future? • Use the Energy Information Cards (sheets C2). • Each group of (3 – 4) will produce a poster of ONE sources of energy. This will be used in a short presentation (2 mins max) to the class. • Include: • information on the energy changes that are taking place, • the advantages and disadvantages of each source and • the ability to provide clean, affordable, plentiful and reliable energy.

25. Energy for the future – the vote • Groups should now VOTE on which source of energy they thought was the best for meeting future demands giving reasons for their answers. • Answer to the questions from the workcard, Future Energy will be used to decide on the best plan for our future energy needs. • Remember that issues of global warming and energy supply will affect you in your lifetime so you really should have an opinion.

26. Future energy 1 • The pie chart shows the various sources of energy we use, nuclear, wind, solar, hydro, gas, coal, micro-generation, wave and biomass.

27. Future energy 2 • Just one energy source will not supply all our future needs. There will need to be a mix of more than one source. • The sources we use must be sustainable. • That means they will provide clean, reliable, plentiful and affordable energy. • We must avoid using energy sources that lead to an increase in the levels of carbon dioxide in the atmosphere as this leads to global warming. • E.g. we must avoid burning fossil fuels (coal, oil, gas) as this would release more CO2 into the atmosphere.

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