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7J Electrical Circuits Electrical energy, circuits and solving problems. More… Tuesday, 27 March 2012 1 INDEX Lesson 1: How much do you know? Homework task 1 Lesson 2: Connecting basic circuits Lesson 3: Electric current Homework task 2 Lesson 4: What do your results show? What if we used a different type of circuit? Lesson 5: Series & Parallel. Dealing with the results. Where to put the ammeter. Lesson 6: Resistance Homework task 3 Lesson 6b: Analysis Lesson 7: Applying your knowledge Lesson 8: Lesson 9: Assessment Tuesday, 27 March 2012 INDEX 2 Lesson 1 How much do you know? Tuesday, 27 March 2012 3 Equipment BBC Revisewise DVD (orange disc) BBC DVD – Class Clips 1 BBC DVD Wan2TlkScience Old 4.5v battery (to show insides) Mini whiteboards Study guides (red, yellow & green) Year 7 electricity MATs Level MATs 4 & 5 Handouts Generator demonstration Tuesday, 27 March 2012 INDEX 4 Lesson objectives Refresh your learning from year 6. Discover ways in which ELECTRICITY is more advanced in KS3. Refresh your skills in explaining how and why things happen. Tuesday, 27 March 2012 INDEX 5 A bit of input and a KEY QUESTION Revisewise DVD CIRCUIT DIAGRAMS – A reminder of what you learnt last year. Key Stage 3 Bitesize. Draw and label the circuit diagram symbols for the following components: Light bulb (lamp) 4.5 volt battery (make sure you get it right) switch Tuesday, 27 March 2012 INDEX 6 … and a bit more Draw a circuit diagram with a switch, a battery and two bulbs. Set the diagram out so that the switch will turn both bulbs on together. Add labels and a caption. Tuesday, 27 March 2012 INDEX 7 More input 2. Some materials carry electricity well. What name do we give to materials that carry electricity well? ‘Materials that carry electricity well are called … ‘ 1. BBC Class Clips ELECTRICITY part 1 3. Some materials are called Wan2TlkScience. electrical insulators. Explain We will look at some of your work what an ‘electrical insulator’ to judge how well you explained. is. Tuesday, 27 March 2012 INDEX 8 Power source Power Station: A huge machine What is a power station for? To change the energy in mucky coal into something more useful… Electrical energy Tuesday, 27 March 2012 INDEX 9 The power station converts the chemical fuel energy into… electrical energy. It’s and energy conversion… Chemical energy into electrical energy. Tuesday, 27 March 2012 INDEX 10 Key Questions (use your study guide) 1. Some materials carry electricity well. 5.Draw and label the circuit diagram What name do we give to materials that symbols for the following components: carry electricity well? ‘Materials that · Light bulb (lamp) carry electricity well are called … ‘ · 4.5 volt battery 2. Some materials are called electrical · switch insulators. Explain what an ‘electrical · motor insulator’ is. · buzzer 3. Draw a circuit that you could use in 6.Fossil fuels are the main energy sources class to decide whether or not different used to generate electricity. Name two materials will carry electricity. Label the fossil fuels, state why they are called ‘fossil’ diagram. Add a short paragraph to and describe how the energy came to be in explain how it works. these fuels. (Full sentences please! Could 4. Batteries are made from individual even be a paragraph!) cells. Dry cells produce 1½ volts each. 7.Draw a circuit diagram with a switch, a How many cells make a 4½ volt battery. battery and two bulbs. Set the diagram out Explain how you know. so that the switch will turn both bulbs on together. Tuesday, 27 March 2012 INDEX 11 Evaluation I am able to explain clearly. My teacher will be able to see that I understand. marks out My drawings are of 5 accurate. Tuesday, 27 March 2012 INDEX 12 Homework task 1 Complete all the key questions. use your study guide Tuesday, 27 March 2012 INDEX 13 Lesson 2 Connecting basic circuits Tuesday, 27 March 2012 14 Equipment Study guides Old 4½v battery to show 3 cells inside Tuesday, 27 March 2012 INDEX 15 Objectives To learn that batteries are made of individual cells that are connected together. To learn to identify faults in basic circuits. To check your ability to draw clear diagrams. To revise drawing proper circuit diagrams. Tuesday, 27 March 2012 INDEX 16 What I am looking for Drawings that show each circuit before and after the fault was mended. Clear drawings that show where the wires are connected. Captions that describe what the drawings are about. Working quickly to finish the task. Tuesday, 27 March 2012 INDEX 17 Safety Old battery cells can release nasty chemicals. Wash skin and clothing if there is any contact. Tuesday, 27 March 2012 INDEX 18 Instructions 1. Find the page called ‘Basic Circuits’ in the study guide. 2. Title & date. 3. Draw each circuit with its faults and again, with its faults mended. Add a caption to each one. (Use about ½ page for each pair). See example 4. Finally, draw each mended circuit as a circuit diagram. Tuesday, 27 March 2012 INDEX 19 Example Your teacher will show you how to do this one. back to instructions faulty circuit mended circuit circuit diagram caption Tuesday, 27 March 2012 INDEX 20 Faulty circuits INDEX Evaluation I am able to draw very clearly. I could easily see what the faults were. smiley I finished my work by the faces end of the lesson. Tuesday, 27 March 2012 INDEX 22 Lesson 3 Electric current click here to see some Tuesday, 27 March 2012 23 Objectives… To learn how electricity flows in a circuit. To learn how to use an ammeter. To learn about resistance. To work together as a group. Tuesday, 27 March 2012 INDEX 24 Teams Sorting out your work team. Tuesday, 27 March 2012 INDEX 25 By the end of the lesson… You will have worked well in a team to: Make a table of results. Make a graph of the results. Written a description or an explanation of how the number of bulbs affects the current. Tuesday, 27 March 2012 INDEX 26 Equipment Transformers Crocodile wires Ammeters 2.2v bulbs Study guides Tuesday, 27 March 2012 INDEX 27 Safety Electric wires can get very hot if there is a fault. Never connect anything directly to the mains. (Shocking!) Tuesday, 27 March 2012 INDEX 28 Input… BBC Wan2Tlk Science Circuits, conduction & components Questions coming up… Tuesday, 27 March 2012 INDEX 29 Millionaire 1. The current flows around the circuit… [A. Both ways, meeting in the middle] [B. One way] [C. Nothing actually flows] 2. The particles that move are called… [A. Atoms] [B. Electricals] [C. Electrons] 3. The more bulbs you add to a circuit… [A. There is more resistance] [B. There is less resistance] [C. The current will not be affected] Tuesday, 27 March 2012 INDEX 30 Measuring the current You can use an ammeter to measure the current in a circuit. If you add more bulbs to the circuit, will there be more or less current? Tuesday, 27 March 2012 INDEX 31 STUDY GUIDE: Practical Current flow in electrical circuits. +2v X Predict. Which of these three circuits will allow the most electricity to flow? A +2v Explain why you think that. B Test. +2v Try all three circuits and get some results. Try 4 bulbs too. Tuesday, 27 March 2012 INDEX 32 End of lesson checklist and homework task. Table of results fixed into book. Graph. Description or explanation about how the number of bulbs in the series circuit affects the current. This must be completed as HOMEWORK. Tuesday, 27 March 2012 INDEX 33 Evaluation Our team worked well together. We helped each other with writing the cheesy explanation. grins We all know how to use the ammeter and get decent results. Tuesday, 27 March 2012 INDEX 34 Lesson 4 What do your results show? What if you used a different type of circuit? Tuesday, 27 March 2012 35 Equipment Transformers Crocodile wires Ammeters 2.2v bulbs Study guides Graph paper Tuesday, 27 March 2012 INDEX 36 Objectives To learn that current is measured in amps. To learn to look carefully at your results. To learn to design a graph that will show what your results mean. To learn that there are other ways to build a circuit. Tuesday, 27 March 2012 INDEX 37 Expectations You will decide if the number of bulbs affects the current in the circuit. You will draw a graph that clearly illustrates what you found out. You will build parallel circuits and measure the current. Tuesday, 27 March 2012 INDEX 38 Part 1 WORK IN PAIRS Look at your results. Does the number of bulbs affect the current in the circuit? [YES/NO] Design a statement that clearly states how the number of bulbs affects the current. [Write a sentence to read to the class] Tuesday, 27 March 2012 INDEX 39 Graph your results What type of graph will you draw? Now draw graphs to make your results very clear to your reader. Tuesday, 27 March 2012 INDEX 40 Graph check list • The y axis is clearly calibrated. • Both axes are labelled. • The graph has a caption to describe what it shows. Tuesday, 27 March 2012 INDEX 41 Part 2: Building a different type of circuit. This is a parallel circuit. Try it, and measure the current. Try 3 bulbs, even 4 if you can. Plot a graph like the one you did for the series circuit. Compare the two graphs. Write a short statement to say what you noticed. Tuesday, 27 March 2012 INDEX 42 Evaluation Current is measured in ______. Hold up your graph so that we can see how clear it is. The two types of circuit are _____ and _____. Next lesson… We will be sorting out why our two graphs were different. Tuesday, 27 March 2012 INDEX 43 Lesson 5 Series & parallel circuits Dealing with the results Deciding where the ammeter goes. Tuesday, 27 March 2012 44 Equipment Ammeters Crocodile wires Transformers 2v bulbs Results tables Graph paper Mini-whiteboards, pens & erasers. DVD Wan2Tlk Science Tuesday, 27 March 2012 INDEX 45 Objectives Learn the differences between series and parallel circuits. Learn how to use graphs to compare the results effectively. Learn about where the ammeter fits in a circuit. Tuesday, 27 March 2012 INDEX 46 Expectations By the end of this lesson… You should know what series and parallel circuits look like. You should know how to make a useful graph of your results. You should know where to put the ammeter in a circuit. Tuesday, 27 March 2012 INDEX 47 Part 1: Series & parallel Work in pairs: Draw Now draw a parallel a series circuit with 3 circuit with 3 bulbs on bulbs on one side of the other side. your mini- whiteboard. Wan2Tlk Science: Series & Parallel Circuits [BBC DVD] Tuesday, 27 March 2012 INDEX 48 Part 2: Useful graphs: Results Current in Current in series parallel Number of lamps circuit circuit 1 0.29 0.29 2 0.21 0.53 3 0.13 0.81 4 0.05 0.95 Tuesday, 27 March 2012 INDEX 49 Part 2: Useful graphs: Series Current in series circuit 0.35 0.3 0.25 Current in series current (amps) circuit 0.2 0.15 0.1 0.05 0 1 2 3 4 num ber of lam ps Tuesday, 27 March 2012 INDEX 50 Part 2: Useful graphs: Parallel Current in parallel circuit 1 0.9 0.8 Current (amps) 0.7 Current in 0.6 parallel circuit 0.5 0.4 0.3 0.2 0.1 0 1 2 3 4 Number of lamps Tuesday, 27 March 2012 INDEX 51 Part 2: Useful graphs: Comparison Current in series and parallel circuits 1 0.9 0.8 Current in amps 0.7 Current in 0.6 series circuit 0.5 Current in 0.4 parallel circuit 0.3 0.2 0.1 0 1 2 3 4 Number of lamps Tuesday, 27 March 2012 INDEX 52 Homework task 2 Complete the two graphs. Trim and fix them into your book. Tuesday, 27 March 2012 INDEX 53 Part 3: Investigating current What difference will it make if the ammeter is placed in different places on a series circuit? Group prediction. Is the current different in different places around the circuit? Tuesday, 27 March 2012 INDEX 54 Investigate Work quickly as a team. Get your results. Write what you noticed into your book. objectives Tuesday, 27 March 2012 INDEX 55 Plenary Reporting back Up to five groups will be asked to read their observations. The objectives were… Learn the differences between series and parallel circuits. Learn how to use graphs to compare the results effectively. Learn about where the ammeter fits in a circuit. Tuesday, 27 March 2012 INDEX 56 Lesson 6 Resistance Tuesday, 27 March 2012 57 Equipment Long & thin resistance wires mounted on wood. Ammeters. Crocodile leads. Transformers or batteries. 2v light bulbs. Graph paper. Results tables. Mini-whiteboards, pens & erasers. Tuesday, 27 March 2012 INDEX 58 Objectives Learn what electrical resistance is. Learn to work together to make predictions. Learn to set up equipment quickly. Learn what is expected to explain at level 5. Tuesday, 27 March 2012 INDEX 59 Expectations By the end of the lesson… Work quickly and systematically to get accurate results. Revise what you know about where to put an ammeter. Write an explanation to explain what happened. Tuesday, 27 March 2012 INDEX 60 Making a prediction Work in pairs How does the length of the wire affect the current? Write a prediction on your whiteboard. Reporting back Tuesday, 27 March 2012 INDEX 61 Safety Thin wires can get hot! Connect your circuit correctly. Never connect directly to the mains supply. Tuesday, 27 March 2012 INDEX 62 Setting up Work in groups of 4 1. Set up the equipment as shown in the diagram. (The ‘roving wire’ is a flexible crocodile lead). 2. Observe what happens to the brightness of the bulb if the crocodile clip is connected at regular intervals along the resistance wire. Tuesday, 27 March 2012 INDEX 63 Measuring the current 3. Place an ammeter in the circuit. Measure the current (amps) when the crocodile clip is connected at regular intervals along the resistance wire. A Where would you put the ammeter in the circuit? Tuesday, 27 March 2012 INDEX 64 Input Video clip explaining resistance. Tuesday, 27 March 2012 INDEX 65 Results Length of wire (mm) Current (amps) 0 and so on… Tuesday, 27 March 2012 INDEX 66 Plenary: Connections Use whiteboards (one each if possible) Describe how the length of the thin wire affects the current in the circuit. Tuesday, 27 March 2012 INDEX 67 Homework task Use graph paper to make a clear graph of your results. Due: Next lesson Take home your results & a sheet of graph paper. You may use a computer if you have one. Tuesday, 27 March 2012 INDEX 68 Lesson 6b Explanations Tuesday, 27 March 2012 69 Objectives To use your results and graph to write a clear explanation. To try to write at level 5. Tuesday, 27 March 2012 INDEX 70 Check list In your book, you should have: Some writing that describes how the length of the wire affects the current. A graph that clearly shows the relationship between the length of the wire and the current. Tuesday, 27 March 2012 INDEX 71 Level 4 Writing at level 4 Level 4 You can use scientific knowledge and words to describe what happens Tuesday, 27 March 2012 INDEX 72 Level 5 Writing at level 5 Level 5 You can use a higher level of scientific knowledge and words to explain and describe what happens You can begin to explain How or Why things happen in terms of either Energy, Forces, Particles or Cells Tuesday, 27 March 2012 INDEX 73 Analysis Length of Current 3. Use your whiteboard to wire (mm) (amps) draft an explanation. 0 4. Listen to other people’s explanations. 5. Copy (redraft) your explanation into your and so book. on… Tuesday, 27 March 2012 INDEX 74 Plenary PAIRS The main new thing I learnt was… What I didn’t really understand was… I am a bit clearer about… My conclusion was level… The most interesting part of the lesson was… Tuesday, 27 March 2012 INDEX 75 Electricity Lesson 7 Solving electrical problems Tuesday, 27 March 2012 76 Equipment Battery modules 6v bulbs, crocodile wires & switches. Dimmers Motors & buzzers Diodes & reed switches Tuesday, 27 March 2012 INDEX 77 Starter Work in a group of 4. Get two bulbs, a battery and a switch. Make a parallel circuit for the two bulbs. Tuesday, 27 March 2012 INDEX 78 Objectives Apply your new knowledge to solve electrical challenges. Revise your knowledge of parallel and series. RECORDING YOUR LEARNING • The study guide suggests ways you could record in your exercise book. • You could also use ICT by downloading your photographs. Tuesday, 27 March 2012 INDEX 79 Challenge 1 Use your study guide An easy one to start with. There are three lights in a kitchen. Design and make a circuit where they all come on with one switch. 1. Remove one bulb from its holder. Do the other two stay on? (They should do!) 2. Draw the circuit as a standard circuit diagram. Add a caption to explain the function of the circuit. 3. Measure the current with an ammeter. Does the current change if one bulb is removed? Add a caption to explain this part. PHOTOGRAPHS Tuesday, 27 March 2012 INDEX 80 Challenge 2 There are three lamps in a shed. Design and build a circuit that allows each lamp to be switched on and off separately. 1. Draw the circuit as a standard circuit diagram. Add a caption to explain the function of the circuit. 2. Measure and record the current with one, two and three bulbs switched on. Record your results and explain any changes. PHOTOGRAPHS Tuesday, 27 March 2012 INDEX 81 Challenge 3 Charles Slime, the well known ‘smoothy’ likes to have ‘mood’ lighting in his sumptuous living room. Design and build the circuit so that he can dim his table lamp. 1. Draw the circuit as a standard circuit diagram. Add a caption to explain the function of the circuit. 2. Measure the voltage across the bulb as the potentiometer is turned. Record your observations. 3. Measure the voltage across the potentiometer as it is turned. Record your observations. 4. Finally, measure the voltage across the bulb and potentiometer together as the potentiometer is turned. Record your observation. 5. Conclude your findings for parts 2, 3 and 4 above. PHOTOGRAPHS Tuesday, 27 March 2012 INDEX 82 Challenge 4 When Sophie goes camping she discovers that the battery in her home-made lamp doesn’t last long. To try to solve the problem she adds a second battery cell. Now the bulb keeps blowing. 1. Draw Sophie’s home-made circuit as a standard circuit diagram, first with one battery cell, then with two. 2. Use your diagram and your knowledge to explain what she is doing wrong. 3. Draw a standard circuit diagram to show how she could have connected the second cell to make the bulb stay alight for longer without blowing it. PHOTOGRAPHS Tuesday, 27 March 2012 INDEX 83 Round ups Scores out of 5… We were able to apply your new knowledge to solve electrical challenges. We think we’ve got the idea of parallel and series. This is the end of this study unit. Tuesday, 27 March 2012 INDEX 84 Lesson 8 Finishing off Tuesday, 27 March 2012 85 Equipment Whiteboards, pens & erasers. KS3 Levels 4 to 5 booklets. ‘How am I doing?’ sheets. Tuesday, 27 March 2012 INDEX 86 Objectives To help complete your learning. To establish what level you are working at. To establish what things you are doing well. To decide on some targets. Tuesday, 27 March 2012 INDEX 87 Bookwork check list 1. Lesson 1: How much do you know? 2. Homework task 1: Complete all the key questions. ‘HOW MUCH DO YOU KNOW?’ 3. Lesson 2: Connecting basic circuits 4. Lesson 3: Electric current 5. Homework task 2: Complete the two graphs. Trim and fix them into your book. 6. Lesson 4: What do your results show? What if we used a different type of circuit? 7. Lesson 5: Series & Parallel. Dealing with the results. Where to put the ammeter. 8. Lesson 6: Resistance 9. Homework task 3: Draw a graph of length of wire against current. 10. Lesson 7: Applying your knowledge to electrical challenges Tuesday, 27 March 2012 INDEX 88 What are you doing well? You can help each other to do this. Make a list of two or three things that your teacher says you are doing well. Tuesday, 27 March 2012 INDEX 89 Now, what about some targets? Look at your partner’s book. What things does the Work in pairs teacher want improved? Choose two things and write them on the Now redraft the targets whiteboard. onto your target Discuss your ideas. sheet. Tuesday, 27 March 2012 INDEX 90 Lesson 9: Assessment Prepare for exams. Get experience of the types of questions. Learn how to work at pace. Tuesday, 27 March 2012 91