2. LookThinkDiscussAgreeShareWrite ENERGY TYPES TRANSFERS AND EFFICIENCY Decode the Hieroglyph to find the title of todays lesson

3. Learning Intention ENERGY TYPES, TRANSFERS AND EFFICIENCY ENERGY TYPES, TRANSFERS AND EFFICIENCY Learning objectives All (must) Identify the main Types of Energy Show how energy can be transferred Explain what efficiency is Be able to calculate efficiency Most (Should) Generate you own energy transfer diagrams Explain why it is important to make machines more efficient Explain why efficiency is important Some (could) Manipulate the efficiency formula to calculate energy Relate efficiency to energy consumption Saturday, 24 October 2015

4. TEHA GIHLT SDUNO HICEAMLC TECLRICAEL ELICAST EITKINC AVITARTIONGAL HEAT LIGHT SOUND CHEMICAL ELECTRICAL ELASTIC KINETIC GRAVITATIONAL There are 8 different TYPES of energy, can you remember what they are? UN-Jumble the words to reveal the eight different types

5. CONSERVATION OF ENERGY ENERGY IS NEVER MADE OR DESTROYED IT SIMPLY CHANGES FROM ONE TYPE TO ANOTHER Electrical Energy Electrical Heat Sound ENERGY IN USEFUL ENERGY OUT WASTED ENERGY Useful sound energy Useful kinetic energy Useful heat energy Wasted light energy Wasted heat energy Other examples 1) This kettle is 80% efficient- what does that mean? 2) How can you make the Kettle MORE efficient? 3) Why is important to make the kettle more efficient?

6. Activity Useful energy transfers Wasted energy transfers A B C D E F Useful and wasted energy What are the useful and wasted energy transfers in these activities?

7. Use the cards and energy types provided to work out the energy transfers from these examples

8. Learning Intention ENERGY TYPES, TRANSFERS AND EFFICIENCY ENERGY TYPES, TRANSFERS AND EFFICIENCY Learning objectives All (must) Identify the main Types of Energy Show how energy can be transferred Explain what efficiency is Be able to calculate efficiency Most (Should) Generate you own energy transfer diagrams Explain why it is important to make machines more efficient Explain why efficiency is important Some (could) Manipulate the efficiency formula to calculate energy Relate efficiency to energy consumption Saturday, 24 October 2015

9. Calculating Efficiency Efficency= Energy out (E out ) Energy in (E in ) E out Eff X E in 1.Calculate the Efficiency of a machine that produces 300 J of Energy for every 500J put into it Eff = E out / E in Eff = 300 / 500 Eff = 0.6 1 mark 1 mark Total 3 marks Eff= 500J 300J 200J 0.6 × 100 = 60%

10. 200,000J 180,000J 20,000J TOTAL ENERGY IN USEFUL ENERGY OUT WASTED ENERGY

11. Energy outEnergy inEffficiency 30J120J 50 J500 J 20 J1000J 300 J0.6 900J0.45 500J 0.02 0.1 0.25 Calculating Efficiency -Your turn 405J

12. Level 6 and 7 Efficiency = (useful energy out/total energy in) x 100 Efficiency questions 1) Name two types of useful energy given out by a hairdryer. 2) A hairdryer wastes 376J for every 1500J of electrical energy it uses. How efficient is the hairdryer? 3) If something is 50% efficient, how many joules of wasted energy will there be if 750J of energy is put in? 4) A wind turbine has an efficiency of 52%. How much kinetic energy from the wind is needed to produce 800J of electrical energy? 5) Below is a Sankey diagram; a visual representation of efficiency. a) What’s the efficiency if the object is a room heater? b)What’s the efficiency if the object is a lightbulb? c)draw your own Sankey diagram for a kettle, which converts 400J of electrical energy. 10J is converted to sound. 300J is converted to heat and the rest is lost as kinetic energy as the kettle vibrates and wobbles. D) What is the efficiency of this kettle? ANSWERS Thermal and Kinetic 74.9 % (accept 75%) 375J 1538.46J 90% 10% Sankey diagram should be to scale with three arrows coming off, all labelled correctly 75%

13. Why is efficiency so important? Pick any object that uses energy, and produce a short presentation about it Say what it’s energy transfers are Why it is important to make it MORE efficient What could happen in the future if we don’t make it more efficient? Relate Efficiency to energy consumption Summarise why efficiency is important Use the following Key words in your presentation: Energy In Energy Out Transfer Efficiency Wasted Energy Conservation Consumption (usage)

14. One thing I learned: One thing I found difficult: A question: Exit ticket

15. 9Ia(7) Efficient cars? 1 Write down two advantages of using electrically powered cars. 2A How efficient is a normal car engine? (Hint: What percentage of energy is converted into useful energy?) bImagine that you start with 100J of energy stored as chemical energy in the fuel in a car. How much of this energy will be usefully transferred by the engine? 3A How efficient is a power station? bIf you started with 100J of energy in the fuel for a power station, how much useful electrical energy would it produce? 4How efficient is an electric car, if you include generating electricity at a power station? (Hint: An electric motor is 75% efficient. Multiply your answer to question by 0.75 to give you the overall efficiency.) 5A Which is truly the most efficient: an electric car or a normal car? b Draw Sankey diagrams to represent the energy transfers in both types of car. 6 Why does a car that runs on only fuel cells have a similar overall efficiency to a car that runs on petrol? 7 Your uncle is thinking of buying a new car that is more efficient, so he will save energy. Write a letter to him, explaining why it might be more efficient to keep the car he has. Electric cars do not have to use batteries. A fuel cell can use hydrogen and oxygen to produce electricity and is very efficient. The only substance that fuel cells give out is water (formed from the hydrogen and oxygen) so they do not cause pollution. Oxygen and hydrogen can be made from water by electrolysis, so electricity must be generated to get the hydrogen and oxygen for the fuel cell. Using fuel cells will only help the environment and save energy resources if renewable resources can be used to generate this electricity. A lot of energy is used when cars are made. It takes about 10 times as much energy to make a new car as the car will use up in fuel. Most cars use engines that run on petrol or diesel. These cars waste 75% of the energy in the fuel and produce waste gases that cause global warming and pollution. Car manufacturers are working to develop more efficient engines but they will only be able to change the efficiency by a few percent. Many people think that we should use electric cars. Electric motors are quieter and only waste about 25% of the energy they transfer, so they should help us to save energy resources. At present, special batteries for cars take a long time to charge and cannot store enough energy for cars to travel long distances but it should not be long before better batteries are developed. But where does the energy come from that charges up the battery? The electricity has to be generated in a power station. Most power stations burn fossil fuels and waste about 65% of the energy they transfer. However, it may be possible in the future to generate more electricity using renewable resources.

16. 9Ia(2) Energy circus 1? C Hand fan 1What is the energy store used by the fan? 2What is the final energy store? 3Describe the energy transfers in as much detail as you can. A Moving toy 1What is the energy store used by the toy? 2Think about the time when the toy is speeding up. How is the energy transferred? Explain your answer. 3Which form of energy in your answer to question 2 is the useful form of energy? 4Once the toy is moving at a steady speed, what are the energy transfers? B Electric fan 1What is the energy store used by the fan? 2What is the final useful energy store? 3What is the final wasted energy store? 4Describe the energy transfers in as much detail as you can. 5Draw a Sankey diagram to represent the energy changes in the fan. D Electric bell or buzzer 1What is the energy store used by the bell or buzzer? 2How is energy transferred from the bell or buzzer to the surrounding air? 3What happens to this energy transfer as you get further away from the bell or buzzer? Why does this happen? 4What is the final form of the energy transferred by the bell or buzzer? (Hint: think about what your answer to question 2 means in terms of particles and their movement.) E Heater 1What is the original energy store used by the heater? 2What is the final energy store? 3Which energy store is wasted energy?

17. TV

18. Car

19. BICYCLE

20. WALKING (ON THE FLAT)

21. CLIMBING STAIRS

22. WIND TURBINE

23. Electrical Heat Sound Light Electrical HeatSound Chemical Kinetic Sound Kinetic Heat Chemical Heat Sound Kinetic Chemical Heat Kinetic Gravitational Kinetic Sound Electrical SoundHeat

24. HEAT CHEMICAL GRAVITATIONAL KINETIC ELECTRICAL SOUND LIGHT HEAT CHEMICAL KINETIC ELECTRICAL SOUND CHEMICAL SOUND HEAT KINETIC

25. YESI have enjoyed the lesson and learnt a lot and completed my class activity. SOMEI have understood some of the work and haven’t finished it all NOI have found it difficult to learn today and I have done very little work

26. Science Department Marking your work S trength Say what you have done well T arget This is something that you could do to improve your work and/or take the next step forward. E ffort a comment about your overall effort here. Sometimes this will be a number. 1- Excellent 2 – Good effort 3 – Satisfactory 4 - More effort needed P upil comment write your own pupil comment. It should show how well you think that you have understood the work.