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7J Electrical Circuits

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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

				
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