7J Electrical Circuits

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7J Electrical Circuits

• Electrical energy, circuits and solving problems.

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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
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Lesson 1

• How much do you know?

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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
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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.

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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

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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.
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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 3. Some
materials are called electrical insulators.
Explain what an electrical insulator is.
1. BBC Class Clips ELECTRICITY part 1
Wan2TlkScience.
We will look at some of your work to judge how
well you explained.
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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
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The power station converts the chemical fuel
energy into
electrical energy.
Its and energy conversion Chemical energy into
electrical energy.
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Key Questions (use your study guide)
 1. Some materials carry electricity well. What
name do we give to materials that carry
electricity well? Materials that carry
electricity well are called 2. Some
materials are called electrical insulators.
Explain what an electrical insulator
is. 3. Draw a circuit that you could use in class
to decide whether or not different materials will
carry electricity. Label the diagram. Add a short
paragraph to explain how it works. 4. Batteries
are made from individual cells. Dry cells produce
1½ volts each. How many cells make a 4½ volt
battery. Explain how you know.
5.Draw and label the circuit diagram symbols for
the following components  Light bulb
(lamp)  4.5 volt battery  switch  motor  buzze
r 6.Fossil fuels are the main energy sources used
to generate electricity. Name two fossil fuels,
state why they are called fossil and describe
how the energy came to be in these fuels. (Full
sentences please! Could even be a
paragraph!) 7.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.
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Evaluation

• I am able to explain clearly.
• My teacher will be able to see that I understand.
• My drawings are accurate.

marks out of 5
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Homework task 1
Complete all the key questions.
use your study guide
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Lesson 2

• Connecting basic circuits

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Equipment
Study guides Old 4½v battery to show 3 cells
inside
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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.

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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.

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Safety
Old battery cells can release nasty
chemicals. Wash skin and clothing if there is any
contact.
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Instructions

• Find the page called Basic Circuits in the
  study guide.
• Title date.
• 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
• Finally, draw each mended circuit as a circuit
  diagram.

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Example
Your teacher will show you how to do this one.
back to instructions
faulty circuit
mended circuit
caption
circuit diagram
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Faulty circuits
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Evaluation

• I am able to draw very clearly.
• I could easily see what the faults were.
• I finished my work by the end of the lesson.

smiley faces
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Lesson 3

• Electric current

click here to see some
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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.

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Teams
Sorting out your work team.
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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.

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Equipment
Transformers Crocodile wires Ammeters 2.2v bulbs
Study guides
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Safety
Electric wires can get very hot if there is a
fault.
Never connect anything directly to the mains.
(Shocking!)
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Input
BBC Wan2Tlk Science Circuits, conduction
components
Questions coming up
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Millionaire

• The current flows around the circuit A. Both
  ways, meeting in the middle B. One way C.
  Nothing actually flows
• The particles that move are called A. Atoms
  B. Electricals C. Electrons
• 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

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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?
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Practical
STUDY GUIDE Current flow in electrical circuits.
Predict. Which of these three circuits will allow
the most electricity to flow? Explain why you
think that. Test. Try all three circuits and
get some results. Try 4 bulbs too.
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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.

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Evaluation

• Our team worked well together.
• We helped each other with writing the
  explanation.
• We all know how to use the ammeter and get decent
  results.

cheesy grins
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Lesson 4

• What do your results show?
• What if you used a different type of circuit?

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Equipment

• Transformers
• Crocodile wires
• Ammeters
• 2.2v bulbs
• Study guides
• Graph paper

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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.

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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.

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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

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Graph your results
What type of graph will you draw?
Now draw graphs to make your results very clear
to your reader.
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Graph check list

• The y axis is clearly calibrated.
• Both axes are labelled.
• The graph has a caption to describe what it
  shows.

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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.

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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.
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Lesson 5

• Series parallel circuits
• Dealing with the results
• Deciding where the ammeter goes.

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Equipment

• Ammeters
• Crocodile wires
• Transformers
• 2v bulbs
• Results tables
• Graph paper
• Mini-whiteboards, pens erasers.
• DVD Wan2Tlk Science

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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.

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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.

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Part 1 Series parallel
Work in pairs Draw a series circuit with 3 bulbs
on one side of your mini-whiteboard.
Now draw a parallel circuit with 3 bulbs on the
other side.
Wan2Tlk Science Series Parallel Circuits BBC
DVD
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Part 2 Useful graphs Results
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Part 2 Useful graphs Series
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Part 2 Useful graphs Parallel
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Part 2 Useful graphs Comparison
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Homework task 2
Complete the two graphs. Trim and fix them into
your book.
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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?
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Investigate
Work quickly as a team. Get your results. Write
what you noticed into your book.
objectives
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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.

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Lesson 6

• Resistance

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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.
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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.

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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.

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Making a prediction
Work in pairs
How does the length of the wire affect the
current?
Write a prediction on your whiteboard.
Reporting back
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Safety
Thin wires can get hot! Connect your circuit
correctly. Never connect directly to the mains
supply.
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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.
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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?
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Input
Video clip explaining resistance.
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Results
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Plenary Connections

• Use whiteboards (one each if possible)
• Describe how the length of the thin wire affects
  the current in the circuit.

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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.

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Lesson 6b

• Explanations

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Objectives

• To use your results and graph to write a clear
  explanation.
• To try to write at level 5.

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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.

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Level 4
Writing at level 4
Level 4 You can use scientific knowledge and
words to describe what happens
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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
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Analysis
3. Use your whiteboard to draft an explanation.
4. Listen to other peoples explanations.
5. Copy (redraft) your explanation into your book.
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Plenary
PAIRS

• The main new thing I learnt was
• What I didnt really understand was
• I am a bit clearer about
• My conclusion was level
• The most interesting part of the lesson was

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Electricity Lesson 7

• Solving electrical problems

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Equipment

• Battery modules
• 6v bulbs, crocodile wires switches.
• Dimmers
• Motors buzzers
• Diodes reed switches

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Starter
Work in a group of 4. Get two bulbs, a battery
and a switch. Make a parallel circuit for the two
bulbs.
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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.

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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
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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.
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• 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
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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.
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• 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
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Challenge 4

• When Sophie goes camping she discovers that the
  battery in her home-made lamp doesnt last long.
  To try to solve the problem she adds a second
  battery cell. Now the bulb keeps blowing.
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• 1. Draw Sophies 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
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Round ups

• Scores out of 5
• We were able to apply your new knowledge to solve
  electrical challenges.
• We think weve got the idea of parallel and
  series.

This is the end of this study unit.
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Lesson 8

• Finishing off

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Equipment

• Whiteboards, pens erasers.
• KS3 Levels 4 to 5 booklets.
• How am I doing? sheets.

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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.

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Bookwork check list

• Lesson 1 How much do you know?
• Homework task 1 Complete all the key questions.
  HOW MUCH DO YOU KNOW?
• Lesson 2 Connecting basic circuits
• Lesson 3 Electric current
• Homework task 2 Complete the two graphs. Trim
  and fix them into your book.
• 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 Draw a graph of length of wire
  against current.
• Lesson 7 Applying your knowledge to electrical
  challenges

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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.
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Now, what about some targets?
Look at your partners book. What things does the
teacher want improved? Choose two things and
write them on the whiteboard. Discuss your ideas.
Work in pairs

• Now redraft the targets onto your target sheet.

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Lesson 9 Assessment

• Prepare for exams.
• Get experience of the types of questions.
• Learn how to work at pace.