Electrical circuits Unit guide - Physicslocker 1/FILES/Unit J.pdfElectrical energy circuits. electricity

J Unit guideElectrical circuits

© Harcourt Education Ltd 2003 Catalyst 1 This worksheet may have been altered from the original on the CD-ROM. Sheet 1 of 1

Where this unit fits in Prior learningThis unit builds on:ideas introduced in unit 6G Changing circuits and unit 4F Circuits and conductors in the key stage 2scheme of work.

The concepts in this unit are: • Energy transfer in electric circuits.• The abstract concept of current.

This unit leads onto: unit 8J Magnets and electromagnets and unit 9I Energy and electricity.

Framework yearly teaching objectives – EnergyUse a simple model of energy transfer to explain: • the purpose of cells in an electrical circuit• that electric current carries energy to components in an electrical circuit• that energy is transferred to components in both series and parallel circuits.

Expectations from the QCA Scheme of WorkAt the end of this unit …

… most pupils will … … some pupils will not have made somuch progress and will …

… some pupils will haveprogressed further and will …

in terms of scientific enquiry NC Programme of Study Sc1 1a, b, c; 2c, g, i, j, k, l, m

• select and use appropriate equipment to investigate circuits• measure current• identify patterns in their results and draw conclusions

about series and parallel circuits• know about the early ideas to do with the development

of the light bulb• describe hazards associated with electricity and how to

deal with them.

• explore circuits using appropriate equipment• identify patterns in their results and use these to

describe the behaviour of a simple circuit• begin to understand how early ideas

contributed to the development of the lightbulb

• identify and report on hazards associatedwith electricity.

• plan and carry out a systematicinvestigation of series and parallelcircuits to obtain sufficientevidence to draw conclusion

• give examples of the developmentof scientific ideas about electricity

• explain how electricity can behazardous to humans.

in terms of physical processes NC Programme of Study Sc4 1a, b, c

• construct a range of working electrical circuits andrepresent these in circuit diagrams

• state that electric current is the same at all points in aseries circuit and divides along the branches of aparallel circuit

• use a flow model to describe resistance and todistinguish between electric current and energy transferin a circuit

• compare and contrast the advantages of series andparallel circuits in use.

• construct simple electrical circuits andrepresent these diagrammatically

• give examples of useful circuits• state safety rules for use of electricity.

• relate voltage of cells andbatteries qualitatively to energytransfer in circuits

• use a flow model to explain thedifference between electriccurrent and energy transfer

• apply the idea that nerves areelectrical conductors to explainelectrical hazards.

Suggested lesson allocation (see individual lesson planning guides)Direct route

J1Electricalenergy

J2Current affairs

J3Differentcircuits

J4Models of electricity: Thinkabout models of electricity

J5Electricalhazards

Extra lessons (not in pupil book)

Review and assess progress(distributed appropriately)

Additional informationThis unit applies the concept of energy to electrical circuits.

MisconceptionsPupils may think that electric current is some sort of power that makes things go and that current gets used up or burnt up by a bulb. Pupils may thinkthat current flows out of both terminals of a battery and it meets with a clash in the bulb causing light. Some may think that current travels round acircuit from the battery getting used up as it goes round and so there is less current at the end of the circuit.It is important that pupils distinguish between two abstract concepts: electricity as ‘flowing stuff’ and electrical energy as something that isidentified by input and output effects. Its effects are associated with the brightness of bulbs and its origins in the voltage rating of batteries. Thereare necessary simplifications in the treatment, as appropriate to this early unit. Some pupils will confuse current and voltage.

Links with other areas of science and across the curriculumNumeracy: Solving problems, using data. Citizenship: Electrical hazards. Technology: Control systems.

Health and safety (see activity notes to inform risk assessment)Pupils must work with low voltages and under no circumstances experiment with mains electricity.

To make good progress, pupils starting this unitneed to: • know that a complete circuit is required for

electrical devices to work• be able to connect a circuit, draw and

interpret standard electrical symbols forconnection, cell/battery, lamp and switch.

➞ Transition quiz for unit J

J1Lesson planning

guideElectrical energy


Learning outcomes

Most pupils will … Some pupils, making less progress will … Some pupils, making more progress will …

• understand that cells and batteriesprovide electrical energy

• know that electricity is what carriesenergy to make things work, e.g. for alamp to light

• be able to represent circuits usingsymbols and make and test predictionsabout circuits.

• identify what can go wrong in a simple circuitand that a complete circuit is needed for alamp to light up

• know that electricity is what carries energy tomake things work, e.g. for a lamp to light.

• be able to solve puzzles of circuit diagrams withmultiple switches.

Learning objectivesi Electricity carries energy to components in an electrical circuit.ii A cell stores energy and a cell with a higher voltage stores more energy than one with lower voltage.iii More than one cell connected together in a circuit is called a battery.

Scientific enquiryiv Test and make predictions about circuits. (Framework YTO Sc1 7b)

Suggested alternative starter activities (5–10 minutes)

Introduce the unit Share learning objectives Problem solving Capture interest (1) Capture interest (2)

Demo that electricitycan flow through thebody and discussionof electrical safetyissues.

• Find out how energy is transferred toan electrical circuit.

• Find out that cells have differentvoltages.

• Be able to test and make predictionsabout circuits. (Sc1)

Groups of pupilscomplete the circuitin one of fourcircuits.

Connect cells togetherpositive to negative.

Show a video clip ofsafety precautions whenusing electricity.Catalyst InteractivePresentations 1

Suggested alternative main activitiesActivity Learning

objectivessee above

Description Approx.timing

Target group

C H E S

Textbook J1 i, ii and iii Teacher-led explanation and questioning OR pupils work individually,in pairs or in small groups through the in-text questions and thenonto the end-of-spread questions if time allows.

25 min R/G G R S

Activity J1aPractical

i, ii and iv Energy changes Pupils connect cells and switches to motors, lamps,steel wool; and note energy transfers.

10 min ✓ ✓

Activity J1bPaper

iv Switch on! Pupils work in pairs to predict from circuit diagrams whathappens when switches are open and closed. This is a review fromKS2 activity.

15 min ✓ ✓

Activity J1cCatalyst InteractivePresentations 1

iv Support activity for pupils to work out from circuit animations whathappens when switches are open and closed.

20 min ✓

Suggested alternative plenary activities (5–10 minutes)Review learning Sharing responses Group feedback Brainstorming Looking aheadPupils describe how acircuit works.

Whole-class discussion of responseson energy transfers in Activity J1a.

Groups of pupils compare anddiscuss their answers fromActivity J1b.

Will it, won’t it? Pupils suggest what life wouldbe like with no electricity.

Key wordscells, chemical energy, volts, energy, complete circuit, battery, red only: electrical energy,voltage

Out-of-lesson learningHomework J1Textbook J1 end-of-spread questions

J2Lesson planning

guideCurrent affairs


Learning outcomes

Most pupils will … Some pupils, making less progress will … Some pupils, making more progress will …• describe how electrical energy is

transferred to components in a circuitwhen a current flows

• be able to construct circuits andmeasure current using an ammeter

• be able to show how current is not usedup in a circuit.

• begin to understand the idea of current aselectricity flowing in wires

• see that current is not used up in a circuit bymaking measurements with an ammeter.

• explain the relationship between the number ofcells/batteries in a circuit or the number oflamps and the size of the current.

Learning objectivesi The difference between energy and electric current in a circuit.ii Current is not used up in a circuit.iii Changing the number of cells in a circuit affects current.

Scientific enquiryiv Use an ammeter to measure current. (Framework YTO Sc1 7d)v Make predictions about current. (Framework YTO Sc1 7b)vi Present and interpret experimental results through routine use of tables. (Framework YTO Sc1 7f)vii Model current in a variety of ways. (Framework YTO Sc1 7a, h)


Recap last lesson Share learning objectives Word game Brain storming Capture interest

Demo that electricitycan flow through thebody from J1.Or Unit map forElectrical circuits.

• Find out what current is and measure it.• Investigate how changing the components

in a circuit affects the current.• Be able to make predictions about current.

(Sc1)

Play a quick gameof hangman withthe whole classusing words fromthe unit.

Recap ways ofchanging thebrightness of alamp.

Show a simulation to exploreideas about current and ananimated water pipe analogy.Catalyst InteractivePresentations 1


objectivessee above


Target group

C H E S

Textbook J2 i, ii, iii andvii

Teacher-led explanation and questioning OR pupils work individually,in pairs or in small groups through the in-text questions and thenonto the end-of-spread questions if time allows.

25 min R/G G R S


ii, iv and vi All the way round Pupils find out how electric current varies round asimple circuit.

20 min ✓

Activity J2bPractical

iii, iv and v Brighter and dimmer Pupils work in groups to find out how tochange how brightly a bulb shines.

25 min ✓ ✓

Activity J2cPractical

iii, iv, v andvi

Investigating electric current Pupils find out how the currentchanges when the number of cells or bulbs in the circuit changes.

25 min ✓ (✓ ) ✓

Activity J2dCatalyst InteractivePresentations 1

iii and iv Pupils find out how the current changes when the number of cells orbulbs in the circuit changes.

25 min ✓ ✓ ✓ ✓

Activity J2eCatalyst InteractivePresentations 1

ii ICT support version of Activity J2a. ✓

Suggested alternative plenary activities (5–10 minutes)Review learning Sharing responses Group feedback Word game Looking aheadHow to measure currentin an electrical circuit.

Whole-class discussion ofresponses from Activity J2a.

Groups of pupils compare and discusstheir answers from Activity J2b.

Pupils discussword pairs.

Ask pupils to suggest alternativeways of connecting components.

Key wordscurrent, ammeter, amps

Out-of-lesson learningHomework J2Textbook J2 end-of-spread questions

J3Lesson planning

guideDifferent circuits


Learning outcomes

Most pupils will … Some pupils, making less progress will … Some pupils, making more progress will …• use a simple analogy to understand the

idea of resistance and that resistancemakes it hard for the current to flow

• understand how the electric current isthe same at all points in a series circuitand current divides along the branchesof a parallel circuit

• be able to use a water pipe analogy tounderstand series and parallel circuits.

• understand that resistance makes it hard forthe current to flow

• apply their understanding of circuits tounderstand how a series and parallel circuit aredifferent.

• describe how resistance is used in dimmerswitches and fuses

• be able to design and construct series andparallel circuits and explain the limitations to thewater model.

Learning objectivesi The electric current is the same at all points in a series circuit. ii Current divides along the branches of a parallel circuit. iii Design and construct series and parallel circuits.

Scientific enquiryiv Use a model to understand current, resistance and series/parallel circuits. (Framework YTO Sc1 7a, h)v Consider early scientific ideas, including how experimental evidence and creative thinking have been combined to provide scientific explanations.

(Framework YTO Sc1 7a) (red only)vi Describe and explain what results show when drawing conclusions; begin to relate conclusions to scientific knowledge and understanding.

(Framework YTO Sc1 7g)


Recap last lesson Share learning objectives Problem solving Capture interest (1) Capture interest (2)

Pupils look at severalcircuit diagrams andsay what the readingis on each ammeter.

• Find out about series andparallel circuits.

• Be able to use a water pipemodel of electricity. (Sc1)

Demo of circuit withdifferent lengths ofpencil lead.

Show a simulation to illustrate seriesand parallel circuits with the waterpipe analogy.Catalyst Interactive Presentations 1

Set up a simple seriesand parallel circuit andask how they aredifferent.


objectivessee above


Target group

C H E S

Textbook J3 i, ii, iii andiv

Teacher-led explanation and questioning OR pupils work individually, inpairs or in small groups through the in-text questions and then onto theend-of-spread questions if time allows.

25 min R/G G R S


ii, iii, viand vii

Parallel circuits Pupils work in groups to set up their own parallelcircuits and measure the current at three points.

25 min ✓ ✓


ii, iii and vi Lighting circuits Pupils design a circuit with two light bulbs that bothlight brightly.

25 min ✓ ✓

Activity J3cPaper

v Developing the light bulb Pupils study the biographies of three of thescientists involved in developing the electric filament lamp.

20 min ✓


ii, iii and vi This simulation is based on Activity J3b. Pupils can be asked toinvestigate closing switches.

10 min ✓ ✓ ✓ ✓

Activity J3eCatalyst InteractivePresentations 1

vi To illustrate series and parallel circuits using water pipe model. 10 min ✓ ✓ ✓ ✓

Suggested alternative plenary activities (5–10 minutes)Review learning Sharing responses Group feedback Word game Looking aheadPupils describe currentflow in series andparallel circuits.

Whole-class discussion ofconclusions from ActivityJ3a.

Groups of pupils compare anddiscuss their solutions fromActivity J3b.

To check progresspupils play dominoesabout electricity.

Pupils suggest strengths andlimitations of water flow model ofcurrent flow.

Key wordsresistance, series circuits, parallel circuit, red only: filament

Out-of-lesson learningHomework J3. Textbook J3 end-of-spread questions

J4Lesson planning

guideModels of electricity – Thinkabout models of electricity


Learning outcomes


• understand the difference betweenenergy and electric current in a circuit

• use a model to explain ideas aboutelectrical circuits appreciating that ithelps them to imagine what ishappening.

• apply a model to develop and consolidate theirunderstanding.

• be able to explain the strengths and weaknessesof a model of electricity.

Learning objectivesThe structure of this lesson is based around the CASE approach. The starter activities give concrete preparation. The lesson then moves away from theconcrete towards a challenging situation, where pupils need to think. The plenary activities give pupils time to discuss what they have learnt, to committheir understanding to paper and express their ideas verbally to the rest of the class.

Scientific enquiryi Use creative thinking to understand several models of electricity. (Framework YTO Sc1 7a)ii Evaluate the usefulness and limitations of models. (Framework YTO Sc1 7h)


Bridging to the unit Setting the context Concrete preparation (1) Concrete preparation (2)

Discuss the need for a model toexplain electricity and current.

Look at a model village or modelhuman body and compare it with thereal thing.

Show a simulation to illustrate the coaltruck model.Catalyst Interactive Presentations 1

Set up a model railway.

Suggested main activitiesActivity Learning

objectivessee above


Target group

C H E S

Textbook J4 i and ii Teacher-led explanation and questioning OR pupils work individually, inpairs or in small groups through the in-text questions and then ontothe end-of-spread questions if time allows.

25 min R/G G R S

Activity J4aDiscussion

i and ii ‘Class and matches’ model Pupils stand in a circle – all of the class isinvolved in the model to give them experience of using models(kinaesthetic).

10 min ✓ ✓ ✓ ✓

Suggested alternative plenary activities (5–10 minutes)Group feedback Bridging to other topicsPupils discuss how the different models helped them to understandelectricity better.

Pupils discuss how the use of scientific models will help them in othertopics.

Key wordsmodels

Out-of-lesson learningTextbook J4 end-of-spread questions

J5Lesson planning

guideElectrical hazards


Learning outcomes


• consider the hazards of electricity forhumans

• identify key points and sequence ideasfrom secondary sources and preparepresentations.

• identify hazards of electricity for humans andstate safety rules for use of electricity

• with help, e.g. a writing frame, sequence ideasfrom secondary sources which they cancontribute to group presentations.

• apply the idea that nerves are electricalconductors to explain electrical hazards.

Learning objectivesi Finding faults in a circuit.ii Hazards of electricity for humans.iii How fuses and ring mains work.

Scientific enquiryiv Use secondary sources of information and prepare presentations. (Framework YTO Sc1 8d)v Consider early scientific ideas, including how experimental evidence and creative thinking have been combined to provide scientific explanations.

(Framework YTO Sc1 7a)


Recap last lesson Share learning objectives Problem solving (1) Problem solving (2) Capture interest

Recap the water pipeanalogy as a modelfor series andparallel circuits.

• Find out about hazards ofelectricity for humans.

• Find out about fuses.• Be able to present information

from research. (Sc1)

Pupils identify the electricalhazards in a picture on thepupil sheet.

Pupils find electricalhazards in aninteractive tour. Catalyst InteractivePresentations 1

Demo that electricitycan flow through thebody.


objectivessee above


Target group

C H E S

Textbook J5 i, ii and iii Teacher-led explanation and questioning OR pupils work individually, inpairs or in small groups through the in-text questions and then ontothe end-of-spead questions if time allows.

25 min R/G G R S

Activity J5aPaper

i and iii Christmas tree lights Designing new circuits comparing Xmas treelights and ring main model.

25 min ✓


i and iii The weakest link Pupils investigate how a fuse protects a circuit. 20 min ✓ ✓

Activity J5cICT

ii, iv and v Discoveries in electricity Pupils work in small groups using secondarysources to prepare PowerPoint presentations or leaflets on Galvani’s andVolta’s work.

25 min ✓


i Support activity on how a torch works – demonstrating and diagnosingfaults in it.

10 min ✓

Suggested alternative plenary activities (5–10 minutes)Review learning Sharing responses Group feedback Word game Looking aheadPupils summarise keypoints about hazards andelectricity.

Whole-class discussion ofpresentations from ActivityJ5c.

Groups of pupils compare anddiscuss their solutions fromActivity J5a.

Check progress by playing‘bingo’ with key wordsfrom the unit.

Pupils revise andconsolidate knowledgefrom the unit.

Key wordsfault, ring main, fuse

Out-of-lesson learningHomework J5Textbook J5 end-of-spread questions Talk to adults about circuits in the home

J1

© Harcourt Education Ltd 2003 Catalyst 1This worksheet may have been altered from the original on the CD-ROM.

StartersElectrical energy

Sheet 1 of 1

Introduce the unit● Using a 1.5 V battery and a microammeter, demonstrate the

three scenarios on the teacher sheet.

● Explain that this shows that electricity can flow through thebody. The 240 V mains supply is 160 times higher than the1.5 V battery. If electricity from the mains flowed throughthe body, it could be enough to stop the heart beating.

● Make sure pupils understand that mains electricity is muchmore dangerous than batteries, and that they must notinsert wires into electrical sockets. Stress that they mustnever use mains electricity for experiments, and that withwater mains electricity is even more hazardous.

Share learning objectives● Ask pupils to write a list of FAQs they would put on a

website telling people about energy from electricity. Collectsuggestions as a whole-class activity, steering pupils towardsthose related to the objectives. Conclude by highlightingthe questions you want them to be able to answer at the endof the lesson.

Problem solving● Give groups of pupils one of the circuits described on the

technician sheet. Ask them to complete the circuit, and alsoto be ready to report how they did this. Remind them thatbatteries are safe but they should never use mains electricityfor experiments.

● When they have finished, choose a group to explain whythere was not a complete circuit. Ask which other groupshad the same problem. Discuss all four circuits in this way.

Capture interest (1)● Demonstrate that if using several cells, they need to be

connected together correctly. Show what happens whenthey are wrongly connected using a circuit with a lamp.

Capture interest (2)● Ask for pupils’ views about electrical safety before showing a

video clip of safety precautions when using electricity.Conclude by saying that batteries are safe, but that theymust never use mains electricity for experiments and neverput wires in sockets. Emphasise that even professionalelectricians sometimes make mistakes and are electrocuted.


Demo that electricity canflow through the bodyand discussion ofelectrical safety issues.

● Find out how energy istransferred to anelectrical circuit.

● Find out that cells havedifferent voltages.

● Be able to test andmake predictions aboutcircuits. (Sc1)

Groups of pupils completethe circuit in one of fourcircuits.

Connect cells togetherpositive to negative.

Show a video clip of safetyprecautions when usingelectricity.Catalyst InteractivePresentations 1

Introduce the unit Share learning Problem solving Capture interest (1) Capture interest (2)objectives

➔ Technician sheetExpected outcomes1 The lamp has a broken filament.2 Both connections to the lamp are on

the same side.3 The two batteries are different ways

around.4 One wire is not connected.

➔ Technician sheet➔ Teacher sheet

Equipmentseveral cells, a lamp, connecting wires

➔ Catalyst Interactive Presentations 1

© Harcourt Education Ltd 2003 Catalyst 1This worksheet may have been altered from the original on the CD-ROM. Sheet 1 of 1

J1 StartersElectrical energy

Introduce the unit

Technician sheetSupply the following for a demonstration to showthat electric current will flow through the humanbody:

● a 1.5 V battery● an ammeter that can be set to measure

microamps● three connecting wires.

A pupil will hold two connectors and a current ofabout 2 or 3 µA will flow, which will rise with wethands.

J1 Starters

�


Electrical energy

Introduce the unit

Teacher sheet1 Without the battery connected, ask a pupil to

hold a probe from the ammeter in each hand.Show that this gives a zero reading.

2 Connect the battery to the ammeter with onewire. Ask the pupil to hold one probe from thebattery in contact with the palm of one hand,and the second probe from the ammeter inthe other hand, as shown in the diagram. Asmall current will register (about 2 or 3 µA).

3 Repeat this with wet hands to show that thecurrent goes up significantly.

1.5 V battery microammeter

pupil holds onein each hand

1.5 V battery microammeter

pupil holds onein each hand


Problem solving

Technician sheetProvide the following for each set of four circuits:

● a faulty lamp (filament broken)

● a spare bulb

● seven filament lamps (working)

● six batteries

● four switches

● 16 connecting wires.

Use the above equipment to make sets of the following four circuits,labelled 1 to 4 (each group of pupils has circuit 1, 2, 3 or 4):

● circuit 1: a series circuit with a lamp and a battery, but thefilament of the lamp is broken

● circuit 2: a series circuit with a lamp and a battery, but the leadsare both attached to the same side of the lamp

● circuit 3: a series circuit with one lamp and two batteries, but oneof the batteries is the wrong way round

● circuit 4: a complicated spaghetti-like circuit with, say, five lampsand two batteries, but one of the leads is not connected. Thecircuit should be set up so that the leads look muddled.

J1 StartersElectrical energy

J2


StartersCurrent affairs

Sheet 1 of 1

Recap last lesson● Either use the safety starter from Lesson J1 if it was not

used in the last lesson.

● Or draw the outline of the unit map on the board thenask pupils to give you words to add, saying where toadd them. Suggest some words yourself when necessaryto keep pupils on the right track.

● Or give out the unit map and ask pupils to work ingroups deciding how to add the listed words to thediagram. Then go through it on the board as eachgroup gives suggestions.


website telling people about electric current. Collectsuggestions as a whole-class activity, steering pupilstowards those related to the objectives. Conclude byhighlighting the questions you want them to be able toanswer at the end of the lesson.

Word game● Play a game of hangman with the whole class to reinforce

vocabulary and spelling of these key words.

Brainstorming● Recap ways of changing the brightness of a lamp from

Key Stage 2: increase the number of batteries; useconnecting wire of lower resistance or shorter length;possibly increase the voltage of the battery.

● Show pupils a series circuit with a dimly lit lamp. Askthem how they could make it brighter. Give pupils a fewminutes to discuss this in groups then ask for feedback.

Capture interest● Show a water pipe animation and ask pupils to imagine

swimming in a fast-flowing river. Follow the path ofthe water on the screen and think about what happensat junctions and at each point of the circuit. Then askthem to imagine being in a flow of current.

● Look at the electric circuit in the animation, discussingwhat happens at junctions and at components. Matchup with analogous components in the water model.


Demo that electricity canflow through the bodyfrom J1.Or Unit map for Electricalcircuits.

● Find out what current isand measure it.

● Investigate howchanging thecomponents in a circuitaffects the current.

● Be able to makepredictions aboutcurrent. (Sc1)

Play a quick game ofhangman with the wholeclass using words from theunit.

Recap ways of changingthe brightness of a lamp.

Show a simulation toexplore ideas about currentand an animated water pipeanalogy.Catalyst InteractivePresentations 1

Recap last lesson Share learning Word game Brainstorming Capture interestobjectives

Key wordselectrical energy, cell, complete circuit,filament lamp, switch, volts, voltage,battery, positive, negative, current,ammeter, amps

➔ Unit map

Equipmenta battery (1.5 V), a lamp (2.5 V or 3.5 V), a switch, connecting wires, extra batteriesand wires



J Unit mapElectrical circuits

ammeteramps, Abatterycellchemical energycircuit symbolsclass and matches modelcoal truck modelcomplete circuitelectrical energyfault

filament Rfuseparallel circuitresistancering mainseries circuitswitchvoltagevolts, Vwater flow model

Copy the unit map and use these words to help you complete it. You may add words of your own too.

�

Electricity

Energy fromelectricity

Differentcircuits

Modellingelectricity

Current

Electricalhazards

J3


StartersDifferent circuits

Sheet 1 of 1

Recap last lesson● Give out the pupil sheet. As a whole-class activity, ask

individual pupils to say what the reading is on theammeters marked with a question mark.


website telling people about different kinds of electriccircuit. Collect suggestions as a whole-class activity,steering pupils towards those related to the objectives.Conclude by highlighting the questions you want themto be able to answer at the end of the lesson.

Problem solving● Show pupils a circuit with a battery, a lamp and two

crocodile clips positioned quite close together on alength of pencil lead. Remind them of the Key Stage 2experiment using different wires in a circuit like this.

● Ask pupils to predict what will happen to the lampwhen you move the crocodile clips further apart toinclude a longer length of pencil lead in the circuit.

● Move the crocodile clips and discuss the effect. Wastheir prediction correct?

Capture interest (1)● Show a simulation to illustrate series and parallel

circuits with the water pipe analogy. Ask pupils whatthe difference is between the two circuits.

● Explain that there is more than one route around aparallel circuit. Ask pupils to suggest the advantages ofthis.

Capture interest (2)● Set up a series circuit with two or three lamps, and a

parallel circuit with the same number of lamps. Use thesame voltage supply (batteries or low voltage supply)for both and include a switch in each just before thesecond lamp. Demonstrate the effect of the switch inboth circuits.

● Ask pupils to suggest differences between the circuits,such as: the lamps in parallel are brighter; the switchturns all the bulbs off in the series circuit but only onein the parallel circuit.


Pupils look at severalcircuit diagrams and saywhat the reading is oneach ammeter.

● Find out about seriesand parallel circuits.

● Be able to use a waterpipe model ofelectricity. (Sc1)

Demo of circuit withdifferent lengths of pencillead.

Show a simulation toillustrate series andparallel circuits with thewater pipe analogy.Catalyst InteractivePresentations 1

Set up a simple series andparallel circuit and ask howthey are different.

Recap last lesson Share learning Problem solving Capture interest (1) Capture interest (2)objectives

➔ Pupil sheetAnswersA 0.1 A, B 0.2 A, 0.2 A, C 0, D 0.3 A, E 0

➔ Technician sheet

➔ Technician sheet



Recap last lesson

J3 StartersDifferent circuits

A ?

0.1 A

circuit A

A

?

circuit C

A

circuit E

?

circuit D

A A

?A

0.2 A

0.3 A

circuit B

A?A

?A


Problem solving

Technician sheetProvide the following for a demonstration:

● a circuit with a battery or low voltage supply connected to a lamp and two wires ending in crocodile clips

● a length of pencil lead for the crocodile clips to clip onto.

Check that the lamp brightness visibly changes as the crocodile clips are moved closer together or further apart on the pencil lead, including a longer or shorter length in the circuit.

J3 StartersDifferent circuits

J3 Starters

�

Capture interest (2)

Technician sheetProvide the following for a demonstration, set up as shown in the circuit diagrams:

● six lamps in holders

● batteries or low voltage supply (the same for each circuit)

● two switches

● connecting wires.

Different circuits

crocodile clips

pencillead

series parallel


J4


StartersModels of electricity – Thinkabout

Sheet 1 of 1

Bridging to the unit● Remind pupils that this unit considers electric circuits.

We can’t see inside a circuit so we need a model to helpus understand what is happening.

● Ask pupils what parts of the model might represent(such as current and components). Establish that itmust explain what happens.

Setting the context● Look at a model village or a model human body.

● For the model village, discuss the advantages, such asallowing you to look down on the whole area and getan overview of where everything is. Ask pupils whethera model of the school would have helped them to findtheir way around when they first arrived. Think oflimitations of the model, such as: it’s too small for us tosee inside buildings; it may go out of date if the reallandscape or building changes.

● For the model of a human body (or part), discuss theadvantages, such as: there is no blood; you can see allthe body parts just by getting it out of cupboard; youdon’t need to cut open a real body; it’s 3D. Think oflimitations, such as: there is no blood; colours andtextures are not represented; people are not allidentical; it doesn’t allow you to look inside organs;you can’t put it under a microscope to see cells.

Concrete preparation (1)● Show pupils a coal truck model simulation and discuss

what they think each part might represent in anelectrical circuit.

Concrete preparation (2)● Set up a model railway with a train pulling some empty

trucks around a loop of track. Have a point wheretrucks can load and a point where they can unload,preferably without stopping (such as with chutes ortipping trucks).

● Discuss what each part of the model might represent inan electric circuit. Explain the significance of theloading/unloading points (where the trucks collect andgive up energy).

Bridging to the unit Setting the context Concrete preparation (1) Concrete preparation (2)


Discuss the need for a model toexplain electricity and current.

Look at a model village or modelhuman body and compare it withthe real thing.

Show a simulation to illustratethe coal truck model.Catalyst InteractivePresentations 1

Set up a model railway.

Equipmenta model railway circuit

Equipmenta model village, a model human body oranother model such as a ship


J5


StartersElectrical hazards

Sheet 1 of 1

Recap last lesson● Explain to pupils that in the water pipe analogy, the

flow of water through the pipe represents the flow ofcurrent around a circuit. The flow must be the sameeverywhere unless extra water is added or water is lost.Elicit that a water wheel represents a component thatconverts electrical energy to some other form of energy.

● When the water comes to a junction of two pipes it willsplit, some flowing through one and some through theother. The total amount of water will stay the same. Ifthe two pipes are identical then the same amount ofwater will flow through each. Ask whether it is easierfor water to flow through a thick pipe or a thin one.


website telling people about faults and hazards inelectrical circuits. Collect suggestions as a whole-classactivity, steering pupils towards those related to theobjectives. Conclude by highlighting the questions youwant them to be able to answer at the end of the lesson.

Problem solving (1)● Ask pupils to work in pairs or small groups to identify

the electrical hazards in the picture on the pupil sheet.

● Bring the class together and ask individual groups forhazards they spotted. Build up a list on the board.

Problem solving (2)● Show an interactive tour around the house. Ask

individual pupils to come up and click on the electricalhazard in each room. If they are correct, the hazard isexplained. A score of correct identifications is given atthe end, which can be discussed with the class.

● Put a broken bulb in the gap to show that if one bulbblows, all the lights go out.

Capture interest● Repeat the safety demo from Lesson J1 or J2. This

allows different pupils to be part of the demo, and nowalso gives opportunities for reading the meter.

● Explain that mains appliances are carefully designedwith good electrical insulation to prevent users cominginto contact with the wires. Even so, they should notbe used with wet hands.


Recap the water pipeanalogy as a model forseries and parallelcircuits.Catalyst InteractivePresentations 1

● Find out about hazardsof electricity for humans.

● Find out about fuses.● Be able to present

information fromresearch. (Sc1)

Pupils identify theelectrical hazards in apicture on the pupil sheet.

Pupils find electricalhazards in an interactivetour.Catalyst InteractivePresentations 1

Demo that electricity canflow through the body.

Recap last lesson Share learning Problem solving (1) Problem solving (2) Capture interestobjectives

➔ Technician sheet➔ Teacher sheet

➔ Pupil sheet




Problem solving (1)Spot the electrical hazards.

J5 StartersElectrical hazards

Sheet 1 of 1© Harcourt Education Ltd 2003 Catalyst 1This worksheet may have been altered from the original on the CD-ROM.

Running the activityPupils work in groups, ideally with each group working through the whole activity.If there is a shortage of components, groups could be collected into threes, with eachgroup testing one component only.

If you think pupils will not be able to melt the wire wool sensibly and safely,demonstrate this part of the experiment. Alternatively, it may be wise to keep thewire wool supply and give a few strands to each group as they are ready for it.

Pupils may need to find the fault if their circuit does not work. Guide them throughthe process of checking all connections, trying different lamps and finally tryingdifferent cells.

Core: Instructions are given for connecting up the circuits and the headings areprovided for pupils to make their own results table.

Help: This provides a results table and structured questions. The sheet may be givento pupils in addition to the Core sheet for them to fill in their results rather thanmaking their own results table.

Expected outcomesPupils discover that they need a complete circuit before anything happens. Thelamp brightness is independent of which way round the wires are connected, butthe motor reverses. They should see that fewer cells results in a lower energy outputas shown by a dimmer lamp and a slower motor.

The wire wool burns through, and this breaks the circuit.

PitfallsIf you are using standard dry cells, then beware those that are ‘flat’. Note that theycannot be checked with a voltmeter, only across a lamp. Also wires sometimesfracture inside the insulation. It is wise to have a tray for faulty components, so thatthey do not go back into stock. It is good practice to encourage pupils to disconnectcells when they are not using the circuits, to help them last longer.

The wire wool activity is popular, but it runs down the cells quickly, so do not allowpupils to carry it on for too long.

Safety notesEye protection should be worn. The wire wool sparks. Warn pupils that wire woolhas sharp strands. They often penetrate the skin to leave behind minute metal‘splinters’.

AnswersCore and Help:

The results are variable.

The results are variable.

J1aTeacher

activity notesEnergy changes

Practical Pupils build circuits with lamps, motors and wire wool to see a variety of energy outputs, Core, Helpto link with energy in Unit I.

Type Purpose Differentiation

Device Types of energy it Effect of swapping Effect of changing thegives out the wires number of cells

lamp light and heat no change Fewer cells make thelamp dimmer.

motor movement/kinetic, The motor direction Fewer cells make thesound, heat reverses. motor slower.

wire wool light and heat

1

2


EquipmentFor each group:

● four 1.5 V cells in holder● three connecting wires● a 6 V lamp in holder● a 6 V motor in holder● a switch● a few strands of wire wool● a pair crocodile clips● a heatproof mat.

For your informationRunning the activityPupils work in groups, ideally with each group working through the wholeactivity. If there is a shortage of components, groups could be collected intothrees, with each group testing one component only.

If you think pupils will not be able to melt the wire wool sensibly and safely,demonstrate this part of the experiment. Alternatively, it may be wise to keep thewire wool supply and give a few strands to each group as they are ready for it.

Pupils may need help to find the fault if their circuit does not work. Guide themthrough the process of checking all connections, trying different lamps andfinally trying different cells

Core: Instructions are given for connecting up the circuits and the headings areprovided for pupils to make their own results table.

Help: This provides a results table and structured questions. The sheet may begiven to pupils in addition to the Core sheet for them to fill in their results ratherthan making their own results table.

Expected outcomesPupils discover that they need a complete circuit before anything happens. Thelamp brightness is independent of which way round the wires are connected, butthe motor reverses. They should see that fewer cells results in a lower energyoutput as shown by a dimmer lamp and a slower motor.

The wire wool burns through, and this breaks the circuit.

PitfallsIf you are using standard dry cells, then beware those that are ‘flat’. Note that theycannot be checked with a voltmeter, only across a lamp. Also wires sometimesfracture inside the insulation. It is wise to have a tray for faulty components, sothat they do not go back into stock. It is good practice to encourage pupils todisconnect cells when they are not using the circuits, to help them last longer.

The wire wool activity is popular, but it runs down the cells quickly, so do notallow pupils to carry it on for too long.


J1aTechnician

activity notesEnergy changes

Practical Pupils build circuits with lamps, motors and wire wool to see a variety of energy outputs, Core, Help to link with energy in Unit I.


Sheet 1 of 1

J1a


ActivityCore

You are going to connect up some circuits to see electricalenergy changing to other forms of energy.

Obtaining evidence1 Make a table like the one below to record your results. Your

teacher may give you a table to fill in.

2 Connect a battery of four cells to a lamp and switch as shown in the diagram.

3 Switch on. Complete the first two spaces in your table for the lamp.

4 Switch off and swap over the wires to the lamp so that they go to the opposite sides.

5 Switch on and record what happens in your table.6 Take out one of the cells to leave three in the circuit.

Switch on, then repeat with two cells and then one cell. Record what happens in your table.

7 Repeat steps 2 to 6 using a motor instead of the lamp.

8 Put some strands of wire wool on a heatproof mat. Using crocodile clips, connect a battery of four cells to the wire wool as shown.

9 Switch on. Complete the first space in your table for the wire wool.

What happens if you change how many strands of wire wool you use?What happens if you move the crocodile clips closer together?

Energy changes

Device Types of energy Effect of swapping Effect of changingit gives out the wires the number of cells

lamp

� ��

Rememberto switch off thecircuit before you

make anychanges.

� ��

motor

� ��

wire woolheat proofmat

Wear eyeprotection.

Wire wool hassharp strands

– take care not tocut yourself. Whenyou switch on thecircuit, make sureyou are not touchingthe wire wool.

!

2

1

Sheet 1 of 1

J1a


ActivityHelp

Presenting the resultsRecord your results in this table.

The first row has been partly filled in for you.

Energy changes

Investigate what happens when you change the number of strands of wire wool.Investigate what happens when you move the crocodile clips closer together.2

1

Device Types of energy Effect of swapping Effect of changingit gives out the wires the number of cells

lamp light and heat When I swapped the wires When I used three cells,over, the lamp the lamp was

............................................................... ...............................................................

............................................................... ...............................................................

............................................................... ...............................................................

............................................................... ...............................................................

............................................................... ...............................................................

motor

wire wool


Running the activityPupils work individually or in pairs to work out what happens in the circuits onthe sheet when the switches are open and closed. This reinforces the knowledgethat a complete circuit is needed for a lamp to light.

The circuits are straightforward parallel circuits. A table is provided for pupils tocopy and complete. If preferred, the sheet could be used as a write-on disposablesheet, with the pupils instructed to write in the table on the sheet.

AnswersA, C

A, B, C

none

D, E, F

J1bTeacher

activity notesSwitch on!

Paper Pupils gain experience of problem solving in the context of circuits. Core


3

1

2

45 Switches closed Lamps lit

1 none

2 G

3 none

4 none

1, 2 G

1, 3 H

1, 4 none

2, 3 G

2, 4 G

3, 4 I

1, 2, 3 G, H

1, 3, 4 H, I

2, 3, 4 G, I

1, 2, 3, 4 G, H, I

Sheet 1 of 1

J1b


ActivityCore

You are going to look at some circuit diagrams and work outwhat happens when the switches are opened and closed.

Switch on!

Switches closed lamps lit

1

2

3

4

1, 2

1, 3

1, 4

2, 3

2, 4

3, 4

1, 2, 3

1, 3, 4

2, 3, 4

1, 2, 3, 4

AB

circuit 1

C

DE

circuit 2

F

circuit 3

G

H

I

1

2

3

4

Which lamps are lit in circuit 1?Which lamps will be lit in circuit 1 if youclose the switch?Which lamps are lit in circuit 2?Which lamps will be lit in circuit 2 if youclose the switch?Copy and complete the table oppositefor circuit 3. Circuit 3

2

3

4

5

1


Running the activityThe activity sheet suggests a group practical. The teacher may prefer todemonstrate the circuit, in which case there will be sufficient meters to placethem in each position in the circuit, instead of moving them.

The sheet provides a results table for pupils to copy, and instructions to build thecircuit and record the ammeter reading at three positions in the circuit.

Other relevant materialSkill sheet 17: Reading an ammeter

Expected outcomesThe electric current is the same at every point in the circuit.

PitfallsIf you are using standard dry cells, then beware those that are ‘flat’. Note thatthey cannot be checked with a voltmeter, only across a lamp. Also wiressometimes fracture inside the insulation. It is wise to have a tray for faultycomponents, so that they do not go back into stock. It is good practice toencourage pupils to disconnect cells when they are not using the circuits, to helpthem last longer.

If analogue meters are used, they must be checked beforehand to ensure that theywill read the same current. Pupils may be concerned when ammeters givenegative readings. Remind them to swap the wires.

AnswersThe electric current is the same all the way round the circuit.

J2aTeacher

activity notesAll the way round

Practical (or demonstration) Pupils learn how to connect and use ammeters and measure electric current with them. CoreThey show that the current is the same all the way round a circuit.


1




● two 1.5 V cells in holder● five connecting wires● two 2.5 V lamps in holders● a switch● a DC ammeter (check the range is suitable).

For your informationRunning the activityThe activity sheet suggests a group practical. The teacher may prefer todemonstrate the circuit, in which case there will be sufficient meters to placethem in each position in the circuit, instead of moving them.

The sheet provides a results table for pupils to copy, and instructions to build thecircuit and record the ammeter reading at three positions in the circuit.

Expected outcomesThe electric current is the same at every point in the circuit.


If analogue meters are used, they must be checked beforehand to ensure that theywill read the same current. Pupils may be concerned when ammeters givenegative readings. Remind them to swap the wires.

J2aTechnician

activity notesAll the way round

Practical (or demonstration) Pupils learn how to connect and use ammeters and measure electric current with them. CoreThey show that the current is the same all the way round a circuit.


A

Sheet 1 of 1

J2a


ActivityCore

You are going to measure the electric current in differentpositions around a simple circuit.

Obtaining evidence1 Make a table like the one below to record your results.

2 Connect the circuit as shown in the diagram. Switch on.

3 Record the ammeter reading in your table. If the ammeter gives a negative reading, just swap over the two wiresconnecting it.

4 Disconnect the ammeter and reconnect it between the twolamps.

5 Switch on and record the ammeter reading in your table.6 Disconnect the ammeter and reconnect it on the other side of

the circuit, between the switch and the lamp.7 Switch on and record the reading in your table.

Considering the evidenceWhat can you say about the electric current around the circuit?

All the way round

Position of ammeter Ammeter reading in amps

between positive (�) endof battery and lamp

between the lamps

between negative (�) endof battery and lamp

� ��

A

� �


make anychanges.

1


Running the activityPupils work in groups of two or three. It may be more successful to give eachgroup three wires initially, then give them additional wires as they add furthercomponents, to save confusion.

Core: Pupils make a prediction about changing the number of cells and thenumber of lamps. They build the circuits without the aid of a diagram, and writesentences to describe their findings.

Help: Pupils are provided with a diagram of the circuit. Structured questions leadthem to make their predictions and describe their results on the sheet.

Expected outcomesPupils see that more cells supply more energy, so the light is brighter. If there aremore lamps in the circuit, then the energy must be shared between them, so thelight is dimmer.


With 1.5 V cells and 2.5 V lamps the lamps are unlikely to blow, but beware ofpupils collecting more cells from other groups!

AnswersCore:

the number of cells or the number of lamps

The lamp would be brighter because more cells supply more energy.

The lamps would be dimmer because they have to share the energy.

as for Q2 and Q3 above

Check pupils’ predictions.

Help:

cell (or battery), lamp, switch

Missing/correct words are as follows:

energy, brighter, dimmer, the energy must be shared between more lamps.

brighter, dimmer


J2bTeacher

activity notesBrighter and dimmer

Practical Pupils investigate changing number of cells and the number of lamps in a circuit. Core, Help


3

1

2

4

5

3

1

2

4



● two 1.5 V cells in holder● three 2.5 V lamps in holders● five connecting wires.

For your information Running the activityPupils work in groups of two or three. It may be more successful to give eachgroup three wires initially, then give them additional wires as they add furthercomponents, to save confusion.

Core: Pupils make a prediction about changing the number of cells and thenumber of lamps. They build the circuits without the aid of a diagram, and writesentences to describe their findings.

Help: Pupils are provided with a diagram of the circuit. Structured questions leadthem to make their predictions and describe their results on the sheet.

Expected outcomesPupils see that more cells supply more energy, so the light is brighter. If there aremore lamps in the circuit, then the energy must be shared between them, so thelight is dimmer.


With 1.5 V cells and 2.5 V lamps the lamps are unlikely to blow, but beware ofpupils collecting more cells from other groups!

J2bTechnician

activity notesBrighter and dimmer

Practical Pupils investigate changing number of cells and the number of lamps in a circuit. Core, Help


Sheet 1 of 1

J2b


ActivityCore

You are going to find out how to change the brightness of alamp.

PredictingA simple circuit has:● one cell● one lamp● connected in a simple loop with a switch.

If you keep the simple loop and switch, what in this list can youchange?

What do you expect to happen if you use more than one cell?Give a reason for your answer.What do you expect to happen if you use more than one lamp?Give a reason for your answer.

Obtaining evidence1 Connect one cell to one lamp. Switch on and record how

bright it is.2 Connect a battery of two cells to one lamp. Switch on and

record how bright it is now.3 Connect a battery of two cells to two lamps. Are the lamps

brighter or dimmer than in step 2?4 Now try a battery of two cells with three lamps.

Presenting the results5 Write down two sentences to describe what you have found out.

Considering the evidenceUse ideas about energy to try to explain what you have seen.Was your prediction correct?

Brighter and dimmer

2

3

4

5

1


make anychanges.

Sheet 1 of 1

J2b


ActivityHelp

You are going to find out how to change the brightness of a lamp.

PredictingThis simple circuit has just one cell connected in a loop to one lamp, with a switch.

Name the three components in the picture of the circuit.

.............................................................................................................................................................................................

Complete these sentences by underlining the correct words and filling the gaps.

Cells are a store of ...................................... .

I expect that if I add an extra cell to my circuit, then the lamp will be

brighter/dimmer.

I expect that if I add an extra lamp to my circuit, then the light will be

dimmer/brighter. This is because .........................................................................................................

.............................................................................................................................................................................................

Obtaining evidence1 Connect one cell to one lamp. Switch on. Write down how

bright (or dim) it is.2 Connect two cells to one lamp. Look at how bright it is.3 Connect two cells to two lamps. Are the lamps brighter or

dimmer than in step 2?4 Now try two cells and three lamps.

Presenting the resultsComplete these sentences.

More cells in the circuit make the lamp ..............................................................................................

More lamps in the circuit make the lamps ........................................................................................

Was your prediction correct? ..........................

Brighter and dimmer

� �


make anychanges.

2

3

4

1


Running the activityPupils work in groups to build circuits and measure the current as they change thenumbers of cells or lamps.

Core (Help): Pupils copy the results table provided, and follow the instructions tobuild the circuits and measure the current. For Help, there are optional prompts atthe foot of the Core sheet to help pupils consider their results, which can be cutoff if not required.

Extension: Pupils build their circuits from a circuit diagram. As for Core, they copythe results table provided, and follow the instructions to build the circuits andmeasure the current. They also consider the effect of a dimmer switch.


Expected outcomesThe current is higher with two cells than with one. (It is unlikely to be exactlydouble, because of the cell’s internal resistance, and the variation of the filamentresistance with temperature.)

The current is lower with two lamps than with one.

Extension: Varying the slide position or turning the knob on the variableresistance changes the current and the brightness of the lamp.

PitfallsIf you are using standard dry cells, then beware those that are ‘flat’. Note that theycannot be checked with a voltmeter, only across a lamp. Also wires sometimesfracture inside the insulation. It is wise to have a tray for faulty components, sothat they do not go back into stock. It is good practice to encourage pupils todisconnect cells when they are not using the circuits, to help them last longer.

Check that pupils are reading ammeters correctly. Analogue ammeters may bebetter for this activity. If digital ones are used they should be switched to thecorrect range in advance. (Note that some cheaper digital meters have their fusesblown if the large current range is switched during use.)

Pupils may be concerned when ammeters give negative readings. Remind them toswap the wires.

AnswersCore (Help):


a If there are more cells in the circuit then the current is higher/bigger.

b If there are more lamps in the circuit then the current is lower/smaller.

Extension:


If there are more cells in the circuit then the current is higher/bigger.If there are more lamps in the circuit then the current is lower/smaller.

The higher the current, the brighter the lamp or more results are needed to beable to generalise.

J2cTeacher

activity notesInvestigating electric current

Practical Pupils measure current as they change the number of cells and lamps in a circuit. Core (Help), Extension


1

2

3

1

2




● two 1.5 V cells in holder● two 2.5 V lamps in holders● a DC ammeter (check that the range is suitable)● a switch● five connecting wires ● variable resistor (for Extension).

For your information Running the activityPupils work in groups to build circuits and measure the current as they change thenumbers of cells or lamps.

Core (Help): Pupils copy the results table provided, and follow the instructions tobuild the circuits and measure the current. For Help, there are optional prompts atthe foot of the Core sheet to help pupils consider their results, which can be cutoff if not required.

Extension: Pupils build their circuits from a circuit diagram. As for Core, they copythe results table provided, and follow the instructions to build the circuits andmeasure the current. They also consider the effect of a dimmer switch.

Expected outcomesThe current is higher with two cells than with one. (It is unlikely to be exactlydouble, because of the cell’s internal resistance, and the variation of the filamentresistance with temperature.)

The current is lower with two lamps than with one.

Extension: Varying the slide position or turning the knob on the variableresistance changes the current and the brightness of the lamp.




J2cTechnician

activity notesInvestigating electric current

Practical Pupils measure current as they change the number of cells and lamps in a circuit. Core (Help), Extension


A

Sheet 1 of 1

J2c


ActivityCore

You are going to use an ammeter to find out how the current changes when you change the number of cells or lamps in the circuit.

Obtaining evidence1 Make a table like this to record your results.

2 Make the circuit shown in the diagram. Your ammeter may look different from the one shown.

3 Switch on and measure the current. Ask your teacher to check that your reading is correct. Record it in the first row of your table.

4 Add another cell to your circuit. Measure and record the current.5 Add another lamp to the circuit in 4. Measure the current again.6 Predict what the current would be if you had one cell and two

lamps. Write your prediction in your table, then build the circuit and check.

Considering the evidenceWas your prediction correct?Write two sentences to describe what you have found out about how the current changes when you change the number of cells and lamps.

Complete these sentences to answer question :

a If there are more cells in the circuit then the current is ...................................................................

b If there are more lamps in the circuit then the current is .............................................................

Investigating electric current

Components in circuit Current in amps

1 cell, 1 lamp

2 cells, 1 lamp

2 cells, 2 lamps

1 cell, 2 lamps: prediction

1 cell, 2 lamps: actual result A

� �

� �

Don’t leavethe circuit switched

on for long. When youare not recording the

current, switchoff.

2

1

�Help

2

Sheet 1 of 1

J2c


ActivityExtension

You are going to use an ammeter to find out how the currentchanges when you change the number of cells or lamps in thecircuit. You will also find out how a dimmer switch works.


2 Make the circuit shown in the diagram opposite.3 Switch on and measure the current. Ask your teacher

to check that your reading is correct. Record it in the first row of your table.

4 If the lamp doesn’t light and the ammeter reading is zero, then you have not got a complete circuit.● Check all the connections.● Try the circuit with the ammeter removed.● Try a different lamp.● Finally try different cells.● If you still cannot get your circuit to work, ask your teacher

for help.5 Add another cell to your circuit. Measure and record the current.6 Add another lamp to the circuit in 4. Measure the current again.7 Predict what the current would be if you had one cell and two

lamps. Write your prediction in your table, then build the circuitand record the result.

Dimmer switches use variable resistors.

8 Connect two cells, one lamp and a variable resistor in a circuit.Find out and record what happens to the current and thebrightness of the lamp as you adjust the variable resistor.

Considering the evidenceWas your prediction in 7 correct?Write two sentences to describe what you have found out abouthow the current changes when you change the number of cellsand lamps.Do you have enough evidence to make up any general rulesabout the current in a circuit and the brightness of a lamp?

Investigating electric current

Components in circuit Current in amps

1 cell, 1 lamp

A



current, switchoff.

2

3

1


Running the activityYou may want to remind pupils that the current is the same all around a series circuit.

Pupils work in groups to build a parallel circuit and measure the current at threepositions around it. You may need to show them how to ‘stack’ 4 mm plugs or otherconnectors to create parallel connections.

If necessary, point out that it is good practice to lay components out as they appearin the circuit diagram, and then add the connections. Pupils may need reassurancethat topologically equivalent circuits are valid, even thought the junctions are not inexactly the same position as in the diagrams.

Core: Pupils use the circuit diagrams in the table to build their circuits. They make acopy of the table including circuit diagrams to record their results.

Help: Pupils build their circuits from pictures of the circuits. They record their resultsin the table on the sheet, and structured questions lead them to consider theirevidence.


Expected outcomesThe current varies at different points in a parallel circuit, dividing at the branches.The sum of the currents in the branches is equal to the total current.


Check that pupils are reading ammeters correctly. Analogue ammeters may be betterfor this activity. If digital ones are used they should be switched to the correct rangein advance. (Note that some cheaper digital meters have their fuses blown if thelarge current range is switched during use.)


AnswersCore:

No, the current is not the same in all three positions. Pupils should quote theirresults to support this.

If you add the currents measured at positions 2 and 3, the total equals thecurrent at position 1.

Help:

Check pupils’ additions.

no

Missing words are as follows:

bigger than, equal to, smaller than, equal to

J3aTeacher

activity notesParallel circuits

Practical Pupils find the current at different points in a parallel circuit. Core, Help


1

2

3

1

2




● two 1.5 V cells in holder● two 2.5 V lamps in holders● a DC ammeter, range 0–1 A● six connecting wires● a switch.

For your information Running the activityYou may want to remind pupils that the current is the same all around a seriescircuit.

Pupils work in groups to build a parallel circuit and measure the current at threepositions around it. You may need to show them how to ‘stack’ 4 mm plugs orother connectors to create parallel connections.

If necessary, point out that it is good practice to lay components out as theyappear in the circuit diagram, and then add the connections. Pupils may needreassurance that topologically equivalent circuits are valid, even thought thejunctions are not in exactly the same position as in the diagrams.

Core: Pupils use the circuit diagrams in the table to build their circuits. They makea copy of the table including circuit diagrams to record their results.

Help: Pupils build their circuits from pictures of the circuits. They record theirresults in the table on the sheet, and structured questions lead them to considertheir evidence.

Expected outcomesThe current varies at different points in a parallel circuit, dividing at the branches.The sum of the currents in the branches is equal to the total current.




J3aTechnician

activity notesParallel circuits

Practical Pupils find the current at different points in a parallel circuit. Core, Help


AA

A

Sheet 1 of 1

J3a


ActivityCore

You are going to build a parallel circuit and investigate how the electriccurrent splits up in a parallel circuit.

Equipment● two cells ● wires● two lamps ● a switch● an ammeter


2 Build a simple parallel circuit like the top one in the table.3 Measure the current with the ammeter in the circuit at position 1.

● If both lamps light, record the current.● If one or both lamps don’t light, find the problem!

4 Put the ammeter at positions 2 and 3 and measure the current each time.

Considering the evidenceIs the current the same at all points in the parallel circuit?Can you see a relationship between the currents at positions 1, 2, and 3 inthe parallel circuit?

Parallel circuits

Circuit Components in circuit Current in amps

parallel,position 1

parallel,position 2

parallel,position 3

A

A

A

2

1

Sheet 1 of 2

J3a


ActivityHelp

You are going to build a parallel circuit and investigate how theelectric current splits up in a parallel circuit.

Equipment● two cells ● wires● two lamps ● a switch● an ammeter

Obtaining evidence1 Build a simple parallel circuit with

two lamps, two cells and a switch. Put the ammeter at position 1 as shown here.

2 If both lamps light, record the current in the table on Sheet 2. If one or both lamps don’t light, find the problem!

3 Switch off and move the ammeter to position 2, like this. Remember to rejoin the circuit where you remove the ammeter.

4 Switch on and record the current in the table.

5 Repeat steps 3 and 4 for position 3.

Parallel circuits

� ��

ammeter

Position 1

� �

� ��

ammeter

� �

Position 2

� ��

ammeter

� �

Position 3



current, switchoff.

Sheet 2 of 2

J3a


ActivityHelp

Presenting the resultsRecord your results in this table.

Considering the evidenceHow much current is going through both lamps? Work it out by adding the readings at positions 2 and 3. ...................................................................

Is the current the same at all points in the parallel circuit? ................................................................

Complete these sentences using the words below.

The current at position 1 is .................................................. the current at position 2.



The total current at positions 2 and 3 is .................................................. the current at position 1.

Parallel circuits (continued)

Circuit Components in circuit Current in amps

parallel,position 1

parallel,position 2

parallel,position 3

A

A

A

bigger than smaller than equal to

2

3

1


Running the activityPupils work in groups of two or three. You may need to show them how to ‘stack’4 mm plugs or other connectors to create parallel connections.

Core: Pupils design and build a parallel lighting circuit.

Help: Pupils consider the action of a pictured parallel circuit, then build it to see ifthey are correct. If necessary, point out that it is good practice to lay componentsout as they appear in the circuit diagram, and then add the connections. Pupilsmay need reassurance that topologically equivalent circuits are valid, eventhought the junctions are not in exactly the same position as in the diagrams.

Expected outcomesPupils should see that a parallel circuit can have current flowing through onebranch at a time. A master switch turns off the current to all branches.


If the pupils use 1.5 V cells and 2.5 V lamps then the lamps are unlikely to blow,but beware of pupils collecting more cells from other groups!

Answers Core:

The master switch is the one in the single wire to the battery. This switchesoff the current to all the branches. Switches in each branch control thatbranch only.

Help: Missing words are as follows:

both lamps, one lamp, master

J3bTeacher

activity notesLighting circuits

Practical Pupils build a parallel circuit with a master switch to see how the lamps can be Core, Help switched independently or all together.


1

1



● two 1.5 V cells in holder● two 2.5 V lamps in holders● three switches● seven connecting wires.

For your information Running the activityPupils work in groups of two or three. You may need to show them how to ‘stack’4 mm plugs or other connectors to create parallel connections.

Core: Pupils design and build a parallel lighting circuit.

Help: Pupils consider the action of a pictured parallel circuit, then build it to see ifthey are correct. If necessary, point out that it is good practice to lay componentsout as they appear in the circuit diagram, and then add the connections. Pupilsmay need reassurance that topologically equivalent circuits are valid, eventhought the junctions are not in exactly the same position as in the diagrams.

Expected outcomesPupils should see that a parallel circuit can have current flowing through onebranch at a time. A master switch turns off the current to all branches.


If the pupils use 1.5 V cells and 2.5 V lamps then the lamps are unlikely to blow,but beware of pupils collecting more cells from other groups!

J3bTechnician

activity notesLighting circuits

Practical Pupils build a parallel circuit with a master switch to see how the lamps can be Core, Helpswitched independently or all together.


Sheet 1 of 1

J3b


ActivityCore

You are going to design a circuit with two lamps, so that bothlight brightly. Each lamp will have its own switch, and there willbe a master switch, that can switch both lamps off.

Equipment● two cells● two lamps● three switches● wires

Planning1 Draw a circuit that you think will work. Use a battery of two cells.2 Draw a coloured line around your circuit to show the path of the

electricity when just one lamp lights.3 Draw a line in a different colour to show the path when just the

other lamp lights.4 Label the master switch.

Obtaining evidence5 Build your circuit.6 Test that each switch does what you need it to do. If it does not,

look back at your circuit diagram and change it if necessary.

Considering the evidenceExplain why your circuit worked.

Lighting circuits

1

Sheet 1 of 1

J3b


ActivityHelp

You are going to build a circuit with two lamps, that both light brightly. Each lamp will have its own switch, and there will be a master switch, that can switch both lamps off.

Planning

1 Draw a coloured line round the circuit to show the path of the electricity when just switch 1 and switch 2 are closed. Colour the lamp that will light.

2 Draw a line in a different colour to show the path when just the other lamp lights.3 The master switch can switch both lamps off. Label it on the diagram.

Obtaining evidence4 Build the circuit shown in the diagram.5 Test that each switch does what it should do. If not, look back at the picture and

change your circuit if you need to.

Considering the evidenceComplete these sentences using the words below.

Switch 1 controls ........................................... Switches 2 and 3 each control .......................................... .

Switch 1 is the .......................... switch in this parallel circuit.

Lighting circuits

switch 3

switch 2

switch 1

� ��

master both lamps one lamp

1


Running the activityPupils work individually or in pairs to read the biographies of the scientists andanswer the questions on the sheet. They gain an insight into how scientificdiscoveries can stem from the work of several scientists working at different times,and appreciate the commercial value of inventions.

ICT opportunitiesBiographies of Humphrey Davy in the CD-ROM Eyewitness Encyclopedia of Science2.0 (Dorling Kindersley), The Way Things Work (Dorling Kindersley) and Encarta(Microsoft®).

Biographies of Edison in the CD-ROM The Way Things Work and Encarta.Biography of Swan in the CD-ROM The Way Things Work.

AnswersCarbon, because you can heat it to a higher temperature before it melts.

Platinum is much more expensive than carbon.

a carbon dioxide

b platinum oxide

If the number of light bulbs in the pupil’s home is n, the sum is£(n � 5 000 000 � 2)/(4 � 240). If n is 10, the patent was worth about £104 000per year in Britain.

individual answers

J3cTeacher

activity notesDeveloping the light bulb

Paper More able pupils extend their understanding of the historical development of the Extensionlight lamp.


3

1

2

4

5

Sheet 1 of 1

J3c


ActivityExtension

You are going to study the biographies of three of the scientists involved indeveloping the electric filament lamp.

Many materials glow when they are heated. When a material is used as a filament in a lamp,it needs to glow but not melt. Carbon melts at 3652 °C and platinum melts at 1772 °C.

Based on the information above about melting points, which material is more suitablefor the filament of an electric lamp? Explain your answer.Based on your general knowledge about carbon and platinum, what other reason isthere for using carbon rather than platinum?

Before the invention of the vacuum pump, there was a problem with the filamentburning away in the air.

What substance would be made when: a carbon b platinum burned?

Inventors patent their inventions. This means the inventor must be paid a fee by peopleusing the invention.

Imagine that the inventor of the filament lamp received one farthing for every light bulb sold. Try to estimate how much the patent was worth per year in Britain, using the information opposite. Show how you came to this amount of money.Most people think that Thomas Edison invented the electric filament lamp. Imagine youare a friend of Joseph Swan. You visit America in 1885 and you are very surprised that noone has heard of Joseph Swan, and that everyone thinks that electric filament lamps wereinvented by Thomas Edison. Write a newspaper article telling the American public aboutJoseph Swan and his contribution towards the development of the electric filament lamp.

Developing the light bulb

Humphrey Davy was born in Cornwallin 1778. He was a very famousscientist during his lifetime. In 1801,he tried to make an electric filamentlamp with strips of platinum, but theplatinum strips burned.

Joseph Swan was born in Sunderland,England in 1828. He started workingon electric filament lamps in 1848, butthe filaments burned away in the air.He invented the carbon filament lampin 1878, soon after the vacuum pumpwas invented. The pump was neededto take the air out of the bulbs.

Thomas Edison was born in Americain 1847. Edison was a great inventor,who held a world record of 1093patents. Edison invented a carbonfilament bulb in 1879. He workedindependently of Swan, but based hisidea on some of Swan’s early work.

● How many light bulbs are there in your home?● There were approximately 5 million households

in Britain in the late nineteenth century.● An early electric filament lamp lasted 6 months.● There were 240 old pennies in a pound.● A farthing was one quarter of an old penny.

2

3

4

5

1


Running the activityA ‘circuit’ is marked on the floor with chalk or tape. The circle must be bigenough for all members of the class to walk around at once (the pupils should bequite close together).

One teacher, or a trusted pupil, stands at one point on the circle. He or she is thebattery and will put energy into the circuit by giving out matches. Anotherteacher stands opposite, again on the ‘circuit’. He or she is the lamp, and will takeenergy out of the circuit by taking in the matches and striking them.

The pupils stand on the circle. They walk slowly around the circle and collect amatch from the ‘battery’ as they go by, and deliver the match to the ‘lamp’. Thepupils themselves actually represent the charge carriers, but as charge carriershave not been introduced, the moving pupils are considered to represent thecurrent. Pupils can be asked to speed up a little to represent an increase in current,or slow down to represent a decrease in current.

Other relevant materialFor the class:

● chalk or tape to mark a circle on the ground● a large box of very long household safety matches.

PitfallsUse the largest type of household matches, so they are easily seen.

Safety notesIf only one teacher is available, he or she should be the ‘lamp’ (who strikes thematches).

J4Teacher

activity notes‘Class and matches’ model

Practical (demonstration) Pupils experience using models. (no pupil sheets)



Running the activityPupils work individually or in pairs to read the pupil sheet and answer thequestions.

Answers1 series, 2 parallel

In parallel, because when you turn one light off, the rest stay on.

J5aTeacher

activity notesChristmas tree lights

Paper Pupils draw circuits to extend their understanding of the difference between series Coreand parallel circuits.


12

Sheet 1 of 1

J5a


ActivityCore

Old-fashioned tree lights used to all go out if one bulb ‘blew’.This was very annoying because you could not tell immediatelywhich bulb had gone wrong. You had to spend ages replacingeach one in turn.

1 Draw a circuit with six lights in it that would behave this way.2 Now redraw your circuit so that if one bulb blew only that one

would go out.

What name do we give to each of your circuits?In which of these two ways do you think the lights in your houseare connected? Give a reason for your answer.

Christmas tree lights

2

1


J5aActivity

Core

�

Old-fashioned tree lights used to all go out if one bulb ‘blew’.This was very annoying because you could not tell immediatelywhich bulb had gone wrong. You had to spend ages replacingeach one in turn.

1 Draw a circuit with six lights in it that would behave this way.2 Now redraw your circuit so that if one bulb blew only that one

would go out.

What name do we give to each of your circuits?In which of these two ways do you think the lights in your houseare connected? Give a reason for your answer.

Christmas tree lights

2

1


Running the activityPupils work in groups to build a circuit into which they put a copper wire and thenstrands of wire wool to model the effect of a fuse in a circuit. They then use a circuitwith a power supply and ammeter to find out at what current fuse wire will melt.

Try out the experiment yourself with the equipment you have available in school. Ifyou think the group will not be able to melt the wire wool sensibly and safely,demonstrate this first part of the experiment. Limit the wire wool available to a fewstrands for each group.

Experiment in advance with the length of fuse wire and the rating to try and keepthe current and voltage as low as possible.

Make sure that the pupils set the power supply to the lowest DC voltage, and that theyleave the current flowing for perhaps 30 s as the fuse wire will not blow immediately.

Core: Pupils build the circuits shown on the sheet, and plan how they will test fusewire.

Help: Full instructions are given to build the circuits, and structured questions leadpupils to consider their evidence.


Expected outcomesThe copper wire does not burn through but conducts safely.

The wire wool burns through, and this breaks the circuit so the lamp goes out. Thesame happens with fuse wire, depending on the current.


Check that pupils are reading ammeters correctly. Analogue ammeters may be betterfor this activity. If digital ones are used they should be switched to the correct rangein advance. (Note that some cheaper digital meters have their fuses blown if thelarge current range is switched during use.)


The wire wool activity is popular, but it runs down the cells quickly, so do not allowpupils to carry it on for too long.


If pupils have not used low voltage power supplies before you will need to explainhow they should use them safely.

J5bTeacher

activity notesThe weakest link

Practical Pupils use wire wool as a fuse and test various pieces of fuse wire to the current flowing Core, Helpthrough the wire, which will cause it to melt.



J5bTeacher

activity notesThe weakest link (continued)

AnswersCore:

The strands of wire wool melted and broke the circuit.

It can stop a fire starting or electrical equipment being damaged by too high acurrent.

Check pupils’ results – the fuse wire would be useful for currents just underthe current at which it melted.

Help:

The wire wool melted and broke the circuit, so the lamp went out.

The wire wool is much thinner or can’t carry as big a current.

the wire wool

, Check pupils’ results – the fuse wire would be useful for currents just underthe current at which it melted.

3

1

2

3

12

4 5




First test:● three cells● a lamp● copper wire● a few strands of wire wool about 1 cm long● a switch● four connecting wires (two with crocodile clip ends)● a heatproof mat.

Second test:● a low voltage power supply● a DC ammeter● three connecting wires (two with crocodile clip ends)● a variety of low rated fuse wire or fuses (2 A and lower if possible)● a heatproof mat.

For your informationRunning the activityPupils work in groups to build a circuit into which they put a copper wire andthen strands of wire wool to model the effect of a fuse in a circuit. They then usea circuit with a power supply and ammeter to find out at what current fuse wirewill melt.

Try out the experiment yourself with the equipment you have available in school.If you think the group will not be able to melt the wire wool sensibly and safely,demonstrate this first part of the experiment. Limit the wire wool available to afew strands for each group.

Experiment in advance with the length of fuse wire and the rating to try and keepthe current and voltage as low as possible.

Make sure that the pupils set the power supply to the lowest DC voltage, and thatthey leave the current flowing for perhaps 30 s as the fuse wire will not blowimmediately.

Core: Pupils build the circuits shown on the sheet, and plan how they will testfuse wire.

Help: Full instructions are given to build the circuits, and structured questionslead pupils to consider their evidence.

Expected outcomesThe copper wire does not burn through but conducts safely.

The wire wool burns through, and this breaks the circuit so the lamp goes out.The same happens with fuse wire, depending on the current.

J5bTechnician

activity notesThe weakest link

Practical Pupils use wire wool as a fuse and test various pieces of fuse wire to the current flowing Core, Helpthrough the wire which will cause it to melt.



J5bTechnician

activity notesThe weakest link (continued)




The wire wool activity is popular, but it runs down the cells quickly, so do notallow pupils to carry it on for too long.


If pupils have not used low voltage power supplies before you will need to explainhow they should use them safely.

Sheet 1 of 1

J5b


ActivityCore

In this activity you are going to investigate how a fuse protects acircuit.

Equipment● First test: three cells, a lamp, copper wire, wire wool, a switch,

connecting wires (two with crocodile clip ends), a heatproof mat● Second test: a low voltage power supply, an ammeter, connecting

wires (two with crocodile clip ends), a variety of fuse wires or fuses(2 A and lower if possible), a heatproof mat

Obtaining evidence: First test1 Connect up this circuit, using copper

wire between the crocodile clips.2 Switch on and check that the lamp lights.3 Switch off. Replace the piece of wire with

a few strands of wire wool about 1 cm long.4 Switch on and record what happens.

Considering the evidenceIs this what you expected to happen? Can you explain why it happened?(If you did not get the result you expected, can you explain why not?)How can this behaviour be useful in a circuit?

Obtaining evidence: Second test5 Plan how you would test some wire to see

whether it is suitable to be used as fuse wire. Decide how to record your results.

6 Check your plan with your teacher, then carry it out.

Considering the evidenceCould the wire you tested be used as fuse wire? For what current, or range of currents, would it be useful?

The weakest link

� ��

heatproofmat

heatproof mat

��

� �

power supply

2

3

1

Wear eyeprotection.



!

Sheet 1 of 1

J5b


ActivityHelp

In this activity you are going to investigate how a fuse protects a circuit.

Equipment● First test: three cells, a lamp, copper wire, wire wool, a switch,

connecting wires (two with crocodile clip ends), a heatproof mat● Second test: a low voltage power supply, an ammeter, connecting

wires (two with crocodile clip ends), a variety of fuse wires or fuses (2 A and lower if possible), a heatproof mat

Obtaining evidence: First test1 Set up this circuit, using copper wire between

the crocodile clips:2 Switch on and check that the lamp lights.3 Switch off and replace the piece of wire with a

few strands of wire wool about 1 cm long.

Considering the evidenceWhat happened when the current flowed through the thin wire wool?

...................................................................................................................................

What is the big difference between the copper wire and the wire wool?

...................................................................................................................................

Complete this sentence:The weakest link in the circuit was .............................................................................

Obtaining evidence: Second test4 Connect up the circuit shown in the diagram.5 Put a wire between the crocodile clips.6 Switch on for 30 seconds or until the wire melts.7 If the wire melts, record the current in the table.8 If the wire doesn’t melt, increase the current and

try again.9 Repeat steps 5 to 8 with the other wires.

Considering the evidenceCould the wires you tested be

used as fuse wire? ......................................

What current could you

use each one for? .......................................

The weakest link

� ��

heatproofmat

heatproof mat

��

� �

power supply

Wire being tested Current in amps when wire melted

2

3

1

4

5

Wear eyeprotection.



!


Running the activityDivide the class into ability-matched groups if appropriate. Set them a clear timelimit for gathering information.

This activity could spread over two lessons and a homework. Decide whatresources will be available for research. Check whether all pupils can use theinternet, or move the class to the library if necessary.

Decide whether the output is to be in the form of a MS PowerPoint slide show ora leaflet, and if the latter, whether it is to be word processed or not. Decide howthe results of the pupils’ work will be displayed to the rest of the class.

The following websites may be useful:

University of Idaho Department of Chemistry – Galvani

The Italian-American Website of New York – Volta

Electrochemistry pages – Galvani

The Great Idea Finder – Story of the Electric Battery

The Great Idea Finder – Volta

Other relevant materialAccess to a computer connected to the internet, preferably with MS Word,PowerPoint and a printer.

Skill sheet 4: Web searches

Skill sheet 19: Writing frame: Research

ICT opportinitiesThere are opportunities for pupils to carry out an internet search, storeinformation as Word files and present their findings as a PowerPoint slide show orword-processed leaflet.

PitfallsAn overabundance of information could cause pupils to lose sight of their aim inthe activity.

AnswersHe passed current through frogs’ legs.

They carry messages as electric pulses.

An electric current causes our muscles to twitch.

It was a primitive battery.

Batteries.

J5cTeacher

activity notesDiscoveries in electricity

ICT Pupils find out about Galvani and Volta and present their findings as a slide show Coreor leaflet.


3

1

2

4

5

http://www.heinemann.co.uk/hotlinks/url.asp?urlid=5044





Sheet 1 of 1

J5c


ActivityCore

You are going to use books and the internet to research the workof Luigi Galvani and Alessandro Volta. You will then prepare apresentation about their discoveries.

Obtaining evidence1 Find out as much as you can about your topic. Your teacher will

tell you how much time you have to do this. You may find it bestto save what you find out on a computer in Word files. Make sureyou give every file a clear title so you know what information youhave.

2 Try to find out the answers to the questions below for eachscientist. This will help you when you come to write yourpresentation.

What is the connection between Galvani and frogs?What does Galvani’s experiment tell us about the way nervescarry messages to muscles? How does Galvani’s experiment help us to understand the effectsof an electric current on humans?Just over 200 years ago Alessandro Volta invented his ‘voltaicpile’. What was it?What do we use today that is based on Volta’s ‘voltaic pile’?

Presenting the evidence3 Decide whether you are going to:

● print a leaflet or ● make a slide show.

Use the information you have found to make your leaflet or slideshow.

Discoveries in electricity

2

3

4

5

1

J1


PlenariesElectrical energy

Sheet 1 of 1

Review learning● Pupils describe in words how a circuit works. They also

use a circuit diagram to represent what happens and anenergy transfer diagram to represent the energytransfers taking place.

Sharing responses● Write the words on the right on the board.

● Allocate one activity from Activity J1a to each pair ofpupils to describe to the others. Pupils should describethe energy transfers taking place, using as many of thekey words on the board as they can. They summarisethe change using energy transfer diagrams. Lowerattaining pupils may need prompts, such as the teacherproviding the number of stages involved and buildingup the transfer on the board as the pupils work throughwhat they saw and what that indicates in terms ofenergy transfers.

Group feedback● Pupils describe what effect the combinations of

switches have on the circuit.

● Ask pupils to suggest why we use the terms open andclosed to describe the behaviour of a switch rather than‘on’ or ‘off’. (In everyday language we tend to say‘switch the light on’ or ‘turn the light off’.)

Brainstorming● Pupils decide if a circuit presented to them will or

won’t work. They justify their response.

● Pupils can respond by writing yes/no on mini-whiteboards or by raising a hand for yes, or not for no.

● As an alternative, use a ‘traffic light’ system forresponding. Give pupils green cards to hold up for yes,and red cards for no. (You can also use amber cards for‘not sure’.)

Looking ahead● Pupils suggest the consequences of having no electricity

for one day, one month or one year.

● They share their ideas in a class discussion.

Review learning Sharing responses Group feedback Brainstorming Looking ahead

Suggested alternative plenary activities (5–10 minutes)

Pupils describe how acircuit works.

Whole-class discussion ofresponses on energytransfers in Activity J1a.

Groups of pupils compareand discuss their answersfrom Activity J1b.

Will it, won’t it? Pupils suggest what lifewould be like with noelectricity.

WordsChemical energy, electrical energy,energy, energy transfer, light energy, heatenergy, sound energy, movement energy

➔ Pupil sheet


BrainstormingDecide which of these circuits will work. Give your reasons in each case.

J1 PlenariesElectrical energy

a

b c

d

e

J2


PlenariesCurrent affairs

Sheet 1 of 1

Review learning● Pupils describe how to measure current flow using an

ammeter. They could use a flow chart, a cartoon stripor put the written statements on the Pupil sheet intothe correct sequence.

Sharing responses● Ask pupils to compare the data they collected in the

activity.

● Discuss what the pattern in the data shows aboutcurrent flow.

● Suggest how we can use the idea of water flowing toexplain the data about current.

● Discuss where the current comes from.

Group feedback● Ask pupils to summarise in a sentence what they think

is the relationship between the number of cells in acircuit and the current.

● Ask them to say what evidence they have from theactivity to suggest this.

● Discuss whether this evidence is supported by thefindings from all groups.

Word game● Pupils discuss the word pairs (see right). They draw out

what the two words have in common and how theydiffer. They could also identify where the word has adifferent meaning in science and in everyday life.

Looking ahead● Ask pupils to draw different circuit diagrams using the

list of components on the right.

● Ask pupils to show their suggestions and summarise thesuggestions on the board.

● Ask which suggestions provide only one route/loop forthe current to flow and which provide more than oneroute/loop for the current to flow.

● Ask pupils to suggest how the same componentsbehave differently in the circuit that provides only oneroute for the current flow compared to the circuit thathas more than one route.

Review learning Sharing responses Group feedback Word game Looking ahead


How to measure current inan electrical circuit.

Whole-class discussion of responses from Activity J2a.

Groups of pupils compareand discuss their answersfrom Activity J2b.

Pupils discuss word pairs. Ask pupils to suggestalternative ways ofconnecting components.

➔ Pupil sheet

Word pairsCell and batteryElectrical energy and electrical currentVoltage and ampsCircuit and current

ComponentsThree cells, two lamps, one switch andconnector wires



Review learningPut these sentences in order to describe how to use an ammeter tomeasure the current in a circuit.

1 Track round the circuit from the � pole side of the cell/batteryuntil you reach the first component that will connect directly tothe ammeter.

2 First set up your circuit.3 Decide between which two components in the circuit you want

to place the ammeter.4 Connect the remaining � terminal of the ammeter to the

component on the other side of it.5 Locate the � pole side of the cell/battery.6 Connect the � terminal of the ammeter to this component.

J2 PlenariesCurrent affairs

Review learningPut these sentences in order to describe how to use an ammeter tomeasure the current in a circuit.

1 Track round the circuit from the � pole side of the cell/batteryuntil you reach the first component that will connect directly tothe ammeter.

2 First set up your circuit.3 Decide between which two components in the circuit you want

to place the ammeter.4 Connect the remaining � terminal of the ammeter to the

component on the other side of it.5 Locate the � pole side of the cell/battery.6 Connect the � terminal of the ammeter to this component.

Current affairs Plenaries

�

J2

J3


PlenariesDifferent circuits

Sheet 1 of 1

Review learning● Write the words (see right) on the board.

● Ask pupils to use these words to help them describe whatthey have learnt about the current flowing in any seriescircuit and the current flowing in any parallel circuit

Sharing responses● Ask pupils to summarise the pattern in the current

readings in series circuits and in parallel circuits.

● Help pupils to identify the differences in readingsbetween the series and parallel circuits

● Ask pupils to suggest what has happened to the currentin the parallel circuit.

● Help pupils to describe how the model of current flowcan explain what they have observed.

Group feedback● Pupils present their circuit diagrams (either by building

the circuit for others to see or by using a circuitdiagram on the OHT/board).

● Pupils compare their circuits by looking at what is thesame and what is different.

● Ask pupils to describe how the current flow modelexplains how their circuit works.

Word game● Pupils play dominoes using the dominoes from the

Pupil sheet.

● Two players draw five cards each. The rest are left in apile face downwards. The top card is turned over andplaced on the desk to start the game. Player one matchesone of his or her cards to either end of the startingdomino. Then player two takes his or her go. If eitherplayer cannot go then that player must take anadditional card from the pile. The game is over whenone player has no cards left.

Looking ahead● Ask pupils to suggest one strength of the water flow

model of current flow and one weakness.

● Put all the suggestions on the board and summarise themain points.

● Pupils could suggest a model of their own to helpexplain how current flows.

Review learning Sharing responses Group feedback Word game Looking ahead


Pupils describe currentflow in series and parallelcircuits.

Whole-class discussion of conclusions fromActivity J3a.

Groups of pupils compareand discuss their solutionsfrom Activity J3b.

To check progress pupilsplay dominoes aboutelectricity.

Pupils suggest strengthsand limitations of waterflow model of current flow.

WordsParallel, series, circuit, current flow, thesame, greater, less than, ammeter reading,resistance.

➔ Pupil sheet


J3 PlenariesDifferent circuits

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J4


PlenariesModels of electricity – Thinkabout

Sheet 1 of 1

Group feedback● Pupils describe how the models help them visualise

what is happening in the electric circuit.

● They discuss how the coal truck model and thematches model are different from the water flow modeland how they are similar.

● Present them with a circuit that they have not metbefore including an open switch. Ask pupils to predictwhat is likely to happen once the switch is closed,using a model of electricity.

● Remind them that a model allows us to makesuggestions/predictions about new and unexploredcontexts.

Bridging to other topics● Explain that scientists use models to help them

understand many different situations that they can’teasily see or touch.

● Give some examples of other models they will use.

Group feedback Bridging to other topics

Pupils discuss how the different models Pupils discuss how the use of scientific helped them to understand electricity models will help them in other topics.better.


Examples7A Cells that make up all living things7L To understand the solar system7G How the small particles that make

matter behave

J5


PlenariesElectrical hazards

Sheet 1 of 1

Review learning● Each pupil summarises what he or she has learnt about

hazards and electricity in two or three key points. Carryout a class scan and ask individual pupils to share theirpoints.

● Ask pupils to check their key points with the learningobjectives for the lesson.

Sharing responses● Ask each group of pupils to present their PowerPoint

show or leaflet.

● Other pairs/groups ask questions about the work.

Group feedback● Pupils present their circuit diagrams (either by building

the circuit for others to see or by using a circuitdiagram on the OHT/board). Ask them to comparewhat is the same and what is different about theircircuits.

● Pupils list similarities and differences between circuitsin Christmas tree lights and a ring main.

● Ask pupils to describe how the current flow modelexplains how their circuit works.

Word game● Pupils select nine words from the table to write into

their bingo grid.

● Read out definitions from the Teacher sheet in anyorder. Pupils match these to their chosen words. The game is over when a pupil can strike out a line.

● The pupil has to recall the definitions as he or she reads out each word back to the class to check thewinning line.

Looking back● Pupils revise and consolidate knowledge from the unit.

They can use the Unit map, Pupil check list or the Testyourself questions.

Review learning Sharing responses Group feedback Word game Looking back


Pupils summarise keypoints about hazards andelectricity.

Whole-class discussion ofpresentations fromActivity J5c.

Groups of pupils compareand discuss their solutionsfrom Activity J5a.

Check progress by playing‘bingo’ with key wordsfrom the unit.

Pupils revise andconsolidate knowledge fromthe unit.

QuestionsHow did the scientists explain theirfindings?How did the scientists use their discovery?What was the reaction of society to theirwork?

➔ Teacher sheet

➔ Pupil sheet

➔ Unit map

➔ Pupil check list

➔ Test yourself


Word gameBingo!

Choose nine words from the list below and write them in the empty grid.

Cross out each word when you hear the teacher read out itsdefinition.

Shout ‘BINGO!’ when you have crossed out a line of three words onthe card.

The line can be across, down or diagonally.

J5 PlenariesElectrical hazards

current parallel

ring main

fuse

fuse

cell

voltamp

batteryseries

energy transfer

resistance

J5


PlenariesElectrical hazards

Sheet 1 of 1

Word gameRead out the definitions below in any order.

This reduces the amount of flow in a circuit. [resistance]

A protective device which melts if too great an electriccurrent flows through it. [fuse]

The unit of current. [amp]

The unit of voltage. [volt]

Describes the movement of energy from one place toanother. [energy transfer]

The amount of flow in a circuit each second. [current]

A circuit with more than one loop. [parallel]

Describes the electric circuits used in our homes.[ring main]

A circuit with just one loop. [series]

Uses a chemical reaction to push electricity around acircuit. [cell]

A collection of two or more cells, provides the push in anelectric circuit. [battery]

A safety device to prevent electric shocks. [fuse]

J1


SpecialsElectrical energy

1 Match the words to their meanings.

2 When a lamp is switched on it changes electrical energyinto two other kinds of energy.

Choose some of these words to fill in the gaps.

The cell has a store of

............................................ energy

The wires transfer ..................................................

energy from the ............................................

to the ............................................ .

The lamp transfers the energy as

........................................... and ............................................ energy.

Sheet 1 of 3

switch

circuit

cell

This is the energysource for the circuit.

You need to close this to complete the circuit!

This must be complete (no gaps)for electricity to flow round it.

cellelectrical movement

light

heat

chemical lamp

sound

3 Look at the circuits. Some of them won’t work!

a Cellls should be connected:

negative to negative

positive to positive

positive to negative.

b Which circuits are correct? .............................................

c What is wrong with the incorrect circuits?

.........................................................................................................................................................................................................

.........................................................................................................................................................................................................

.........................................................................................................................................................................................................

d What is a battery? Circle the correct answer.

J1


SpecialsElectrical energy (continued)

Sheet 2 of 3

Tick thebox.

a kind of

chicken

two or more cellsjoined together

one cell

on its own

A B

C D

� ��

� ��

J1


SpecialsElectrical energy (continued)

4 These sentences are about how the lamp gives out light. They’re all mixed up! Write numbers in the boxes to put them in order.

The cell is a store of energy.

The hot wire glows and gives out light.

When the cell is connected to the lamp, electricity flows.

The electricity carries energy to the wire.

The energy makes the wire hot.

5 Cross out the wrong words. Underline the right words.

Energy goes into / out of the circuit at the cell. Cells with a high / low voltage store more energy.

Sheet 3 of 3

J2


SpecialsCurrent affairs

1 Look at this circuit.

a Put your finger on the cell where the + sign is. Trace around the circuit to the other side of the batterywhere the – sign is. This is the path the electric current takes to make the lamp light up.

b Draw arrows on the circuit to show how the electric current flows around it.

2 a Cross out the wrong words. Underline theright words.

To measure the current flowing I can usean ammeter / voltmeter. Current ismeasured in joules / amps / volts.

b Where would you put an ammeter to measure the current? Draw an ammeter on the circuit to show where you would put it.

3 Write true or false for each sentence.

a The more cells there are in a circuit, the bigger the push

and the bigger the current. ..........................

b The current is not used up as it flows around the circuit. ..........................

c The current is the same on both sides of a lamp. ..........................

Sheet 1 of 1

��

J3


SpecialsDifferent circuits

1 Label these circuits series or parallel.

2 Cross out the wrong words. Underline the right words.

a In a series / parallel circuit, the lamps are in differentloops.

b In a series / parallel circuit, the lamps are side byside.

c When two lamps are connected in series, they shinemore / less brightly than one lamp alone in a circuit.

d When two lamps are connected in series / parallel,they shine as brightly as one lamp alone in a circuit.

Sheet 1 of 2

a b

c d

A

A

.............................................. ..............................................

.............................................. ..............................................

J3


SpecialsDifferent circuits (continued)

3 Look at these two circuits.

a Which circuit shows two lamps connected in series? .............

b Which circuit shows two lamps connected in parallel? .............

c Will the lamps be brighter in circuit A or circuit B? .............

d If you unscrew one lamp in circuit A, what will happen to

the other lamp? Will it go out or will it stay on? ...............................................................

e If you unscrew one lamp in circuit B, what will happen to

the other lamp? Will it go out or will it stay on? ...............................................................


a In a series circuit, the current is different at different points. ..........................

b In a parallel circuit, the current is shared between the loops. ..........................

c If there is a high resistance, it is easy for the current to flow. ..........................

Sheet 2 of 2

A B

1 You know some important things about electricity. Can you pick them out of this list?

Electricity carries energy to make things work.

There is no energy in electricity.

You need a complete circuit to make a lamp light.

A lamp will light if there is a break in the circuit.

The current is the same on both sides of the lamp.

The current is different in different places in a circuit.

2 Look at Sheet 2. It shows the coal truck model of electricity.

a Match the parts of the model to the electrical ideas.

b The trucks move faster. The current …

… decreases

… increases

… stays the same.

J4


SpecialsModels of electricity

Sheet 1 of 2

Tick theboxes to show

the rightones.

Tick thebox to show

the rightanswer.

the lamp

the cell

the energy

the circuit

railway line

coal mine

coal

power station

J4


SpecialsModels of electricity (continued)

The coal truck modelThe coal trucks move around the railway. They pick upcoal from the mine. They drop the coal at the powerstation. They go back to the mine for more coal. Thetrucks can move quickly or slowly.

Sheet 2 of 2

mine

power station

J5


SpecialsElectrical hazards

1 Sunil has just put new batteriesinto his bike light, but it’s not working.He thinks it’s broken. What shouldhe do to check it out? Tick allthe correct things he could do.

Throw the light away and buy a new one.

Check the batteries are put in the right way round.

Hit the light to see if that will make it work.

Try a new lamp in the light.

Check the wires to see that they are not loose.

2 Use words from this list to complete the sentences.

The electrical circuit in a house is called a ...................................................

The lamps in this circuit are all connected in ............................................

If one lamp is switched off or goes out, the others ...................................................


a Mains electricity contains more energy than the

electricity from a cell. ..........................

b If you have an electric shock, it cannot stop your heart

beating. ..........................

c Not all plugs on electrical appliances have a fuse. ..........................

d If too much electricity flows to the appliance, the fuse

melts and breaks the circuit. ..........................

e If too much electricity flows through wires, they do not

melt and catch fire. ..........................

Sheet 1 of 1

ring mainseries stay on go out parallel

J1 Electrical energy1 switch – You need to close this to complete the

circuit.circuit – This must be complete (no gaps) forelectricity to flow round it.cell – This is the energy source for the circuit.

2 The cell has a store of chemical energy. Thewires transfer electrical energy from the cell tothe lamp. The lamp transfers the energy as heatand light energy.

3 a Cells should be connected positive tonegative.

b circuit Ac Cells are connected positive to positive or

negative to negative.d A battery is two or more cells joined

together.4 1, 5, 2, 3, 45 Energy goes into the circuit at the cell. Cells

with high voltage store more energy.

J2 Current affairs1 a Pupils trace from positive to negative along

the wires.b Arrows drawn along wires from positive to

negative.2 a To measure the current flowing I can use an

ammeter. Current is measured in amps.b Ammeter drawn (circle enclosing an upper

case A) anywhere between lamp and cell.3 a true b true c true

J3 Different circuits1 a series b parallel c parallel d series2 a In a parallel circuit the lamps are in different

loops.b In a series circuit the lamps are side by side.c When two lamps are connected in series,

they shine less brightly than one lamp alonein a circuit.

d When two lamps are connected in parallel,they shine as brightly as one lamp alone in acircuit.

3 a B b A c Ad It will stay on. e It will go out.

4 a false b true c false

J4 Models of electricity1 Electricity carries energy to make things work.

You need a complete circuit to make a lamplight.The current is the same on both sides of thelamp.

2 a coal mine � the cell, coal � the energy,railway line � the circuit, power station � the lamp

b increases

J5 Electrical hazards1 Check the batteries are put in the right way

round.Try a new lamp in the light.Check the wires to see that they are not loose.

2 ring main, parallel, stay on3 a true b false c false

d true e false

J Specials answersElectrical circuits


J1


HomeworkElectrical energy

HELP1 Copy and complete these sentences using the words below.

a Energy goes into the circuit at the ...................................... .

b ...................................... makes the current flow.

c Energy goes out of the circuit at the ...................................... .

2 Look at the circuit opposite.Copy and complete the table to show which lamps will light as you close the switches. The first one has been done for you.

CORE3 a Draw the circuit symbol for:

i a single cellii a lamp (bulb).

b Use the circuit symbols to draw a circuit diagram for the circuit opposite.

c Draw the circuit diagram for the circuit again, but this time add another component (part) that could be used to turn the lamp on and off.

d Copy and complete this energy transfer diagram for the circuit.

Sheet 1 of 2

1

2 3

X

Y

Z

chemicalenergy

stored inthe cell ...................................... energy

in the wires

...................................... energy

...................................... energy

lamp

Switches closed Lamps lit

X only none

X and Y

X and Z

Y and Z

X, Y and Z

cell voltage lamp

J1


HomeworkElectrical energy (continued)

4 Look at the circuit diagrams below. The lamp is off in all the circuits. For each circuit, explain why the lamp is off.

EXTENSION5 A battery contains four cells. Each cell provides 1.5 V of electrical

energy when it is new.

a What is the maximum voltage provided by this battery?

b The battery was used to drive a radio-controlled toy. After twohours of constant use, the toy stopped. Explain why.

c In a different toy, the new battery provided 12 V of electrical energy.Each cell was the same as those in the battery in part a. How many cells are in this 12 V battery?

d Copy and complete the table by matching each electrical itemwith the most appropriate cell in the table.

Sheet 2 of 2

A B C

Type of cell Characteristics Electrical itemor battery

lithium cell reliable and long lasting

mercury cell expensive; can produce both short, high-energy transfers and long, low-energy transfers

lead–acid can be recharged; produces very largebattery energy transfers

dry cell cheap; cannot be recharged; producesonly small energy transfers

Ni–Cad cell can be recharged but produces onlysmall energy transfers and is expensive

● Car : needs a large energy burst tostart the engine.

● Camera: needs a low energy transferto work the light meter, and a largeenergy transfer to charge up the flashunit.

● Torch: needs a small energy transferonly.

● Digital watch: needs only a smallenergy transfer but it is fiddly tochange the cell.

● Radio-controlled car : does not need alarge energy transfer but batteries rundown quickly.

J2


HomeworkCurrent affairs

HELP1 You sometimes see this symbol in a circuit:

What piece of apparatus does the symbol stand for?

2 Copy and complete these sentences, choosing from the words inbold.

a The current/brightness in a circuit is measured in amps.

b The current in a circuit gets bigger/is used up/stays thesame as it goes through a lamp.

c In a simple circuit with one cell and one lamp, the current intothe lamp is bigger than/smaller than/the same as thecurrent out of the lamp.

3 Draw a circuit diagram showing a cell, a lamp and an ammeterconnected together.

CORE4 Look at the diagram. Which part of an

electrical circuit do letters A to E standfor? Choose from the words below.

5 Look at this circuit diagram.

a You want to measure the current flowing through lamp B. Redraw the circuit diagram showing where you would put the ammeter.

b Redraw the diagram again with the ammeter in a different position that would give the same reading.

Sheet 1 of 2

cell

thermostat

lamp

crocodile clips wires

current

Eheat energytransferredto room

Cradiator

Bpipes

DwaterflowA

boiler

C

B

A

A

light and heat energytransferred from lamp

J2


HomeworkCurrent affairs (continued)

EXTENSION6 This table shows how the current varies

with the number of cells in a circuit. The cells are identical.

a Why does the current increase as the number of cells increases?

b Why does the current increase in equal steps?

c What would the current be if you connected 10 of these identical cells together in the circuit?

7 Helen suggested this model to help her to explain how a circuitworks.

a What type of energy is stored in the water at point A?

b What type of energy is transferred to the turbine at point B?

c Is there anything in the model that represents the current in areal circuit? If so, what is it and how does it represent current?

d Is there something that represents a cell? If so, what is it andhow does it represent a cell?

e Explain why the turbine represents a lamp in a real circuit.

Sheet 2 of 2

Number of cells Current in amps

1 0.1

2 0.2

3 0.3

4 0.4

5 0.5

A

B

pump

turbine

directionof turn

waterpumped upto go round

againwaterflowing

J3


HomeworkDifferent circuits

HELP1 Copy and complete these sentences, choosing from the words in

bold.

a A thin piece of wire slows the current down more/less than athick piece of wire.

b If a piece of wire slows the current down, it has a highresistance/current.

c A thick piece of wire has a low resistance, so it is easy/hard forthe current to flow.

2 Five circuit diagrams are shown below.

Copy and complete the table to show which circuits are series andwhich are parallel.

CORE3 Look at the diagrams in question 2.

a Will the lamps be brighter in circuit A or circuit B?

b In which circuit will the lamps have the same brightness as incircuit B?

Sheet 1 of 2

A B C

D E

Series circuits Parallel circuits

J3


HomeworkDifferent circuits (continued)

4 Some circuit diagrams are shown below. Think about themcarefully, then copy and complete the table to show the currentmeasured by each ammeter.

EXTENSION5 Tong’s dad owns a Chinese restaurant. It has a large model dragon

in the centre of the room that is lit up by a bulb inside it. Tong’sdad likes to turn the lights down gradually during the evening toadd a bit of atmosphere.

a What could he add into the dragon lighting circuit to do this?Explain how this would make the bulb gradually dimmer.

One busy evening the bulb failed, so Tong’s dad replaced it with anew one. The new bulb was very dim and the dragon lookedrather pathetic, instead of rather spectacular.

b Suggest what mistake Tong’s dad might have made when hereplaced the bulb, and explain why this made the new bulbshine less brightly. Use the words ‘resistance’ and ‘current’ inyour answer.

Sheet 2 of 2

Ammeter Current in amps

A1 1.5

A2

A3

A4 0.6

A5 0.2

A6

A7

A8 3.0

A9

A10 1.0

A11

A12

A1 A3

A2

A4 A7

A6

A8 A12A9

A5

A10

A11

J5


HomeworkElectrical hazards

HELP1 Look at the circuits below. Some will work. Some have a fault and

won’t work.

Copy and complete the table below.

2 Copy and complete these sentences.

a A fuse is an electrical safety device that melts if …

b Fuse wires have a ...................................... resistance.

c When a fuse wire melts, the electrical energy is transferred as

...................................... energy and ...................................... energy.

d If you get a shock from mains electricity, it can kill because it …

Sheet 1 of 3

A B C

D E

Circuit Will the circuit work? If not, what is the fault?

A

B

C

D

E

J5


HomeworkElectrical hazards (continued)

CORE3 a Draw a circuit, using only a cell, a lamp and connecting wires,

that you could use to find out whether components were faultyor good.

b How would the circuit tell you if a component was:i faulty?ii good?

c Sanjay built a fault-finding circuit and used it to test theheadlight bulbs from his radio-controlled model car.

Copy and complete the table below, using the word faulty orgood in the last column.

d Even with one faulty headlight bulb, the other model carheadlight still worked. What kind of circuit had been used toconnect the model car’s headlights?

4 a The red stop lights on a car are connected in a parallel circuit.Explain why a series circuit is not used for these lights.

b In a hair dryer, the heater and the fan might be connected in aseries circuit. Suggest why this is useful if the fan motor stopsworking.

c It is not helpful to connect fairy lights together using a seriescircuit. Explain why not.

Sheet 2 of 3

Car bulb Fault-finder bulb State of car bulb

left on

right off

J5


HomeworkElectrical hazards (continued)

EXTENSIONLook at this circuit carefully. It contains somethingyou may not have seen before. If the electricity canbypass a lamp without having to go through it, thenit will. In this circuit the electricity will go along thesimple wire and not through the lamp. This meansthat the lamp will not light up. This idea is importantin the questions below.

5 Look at this circuit diagram.Which lamps will be lit if:

a only switch X is closed (on)?

b only switch Y is closed (on)?

c both switches X and Y are closed (on)?

6 Look carefully at the circuit diagram below.

a You want to add a switch or switches that will allow lamps F, Gand H to be turned off whilst lamp E stays on. Redraw the circuitdiagram, adding the switch or switches you need.

b You would like to be able to turn lamp G on and off independentlyof the other three lamps. Draw the circuit diagram again and addone switch only to show how this could be done.

Sheet 3 of 3

Y

X

D

CA

B

E

G

F

H

J1


Homeworkmark schemeElectrical energy

Sheet 1 of 7

Question Answer Mark

1 a Energy goes into the circuit at the cell. 1

b Voltage makes the current flow. 1

c Energy goes out of the circuit at the lamp. 1Underscores show answers; other text copied by pupils.

2 X and Y: 1 1X and Z: 2 and 3 1Y and Z: none 1X, Y and Z: 1, 2 and 3 1

Total for Help 7

HELP


3 a i 1

ii 1

b

2One mark for correct circuit diagram; one mark for using a ruler and drawing with no breaks.

c

1One mark for the correct symbol for a switch inserted somewhere between the cell and the lamp.

d

3Underscores show answers; other text copied by pupils.One mark for each correct answer.

4 A: one cell connected the wrong way round 1B: switch open or off or not closed or not on 1C: break in (top left of) circuit or circuit is not complete 1

Total for Core 11

CORE

Chemical energystored in the

cell electrical energyin the wires

lamp

light energy

heat energy

J1


Homeworkmark schemeElectrical energy (continued)

Sheet 2 of 7


5 a 6 V 1

b All or most of the energy stored in the battery had been transferred. 1

c 8 1

d Lithium cell: digital watch 1Mercury cell: camera 1Lead–acid battery: car 1Dry cell: torch 1Ni–Cad cell: radio-controlled car 1

Total for Extension 8

EXTENSION

J2


Homeworkmark schemeCurrent affairs

Sheet 3 of 7


1 Ammeter 1

2 a The current in a circuit is measured in amps. 1

b The current in a circuit stays the same as it goes through a lamp. 1

c In a simple circuit with one cell and one lamp, the current into the lamp is the same as the current out of the lamp. 1

Underscores show answers; other text copied by pupils.

3

1One mark for the ammeter anywhere between the lamp and the cell.

Total for Help 5

HELP


4 A cell 1B wires 1C lamp 1D current 1E light and heat energy transferred from lamp 1

5 a

1One mark for the ammeter either side of lamp B.

b

1One mark for the ammeter the opposite side of lamp B.

Total for Core 7

CORE

A

A

AB

C

A

AB

C

J2


Homeworkmark schemeCurrent affairs (continued)

Sheet 4 of 7


6 a Increasing the number of cells puts more (electrical) energy into the circuit, so the current increases. 1Accept equivalent answers.

b Each identical cell adds the same amount of extra energy. 1Accept equivalent answers.

c 1.0 A 1

7 a Gravitational 1

b Kinetic 1

c The water 1It flows round the system and goes back to where it started. 1

d The pump 1It supplies energy to the water. 1

e It transfers energy from the flowing water. 1A lamp transfers energy from the flowing current. 1


EXTENSION

J3


Homeworkmark schemeDifferent circuits

Sheet 5 of 7


1 a A thin piece of wire slows the current down more than a thick piece of wire. 1

b If a piece of wire slows the current down, it has a high resistance. 1

c A thick piece of wire has a low resistance, so it is easy for the current to flow. 1Underscores show answers; other text copied by pupils.

2 Series circuits: A, C 1, 1Parallel circuits: B, D, E 1, 1, 1

Total for Help 8

HELP


3 a B 1

b D 1

4 A1 1.5, A2 1.5, A3 1.5 1, 1A4 0.6, A5 0.2, A6 0.4, A7 0.6 1, 1A8 3.0, A9 3.0, A10 1.0, A11 2.0, A12 3.0 1, 1, 1Underscores show answers; other text copied by pupils.

Total for Core 9

CORE


5 a A dimmer switch or length of wire with a high resistance 1Turning down the dimmer switch or moving a connection along the resistance wire includes more of the resistance wire in the circuit, 1increasing the resistance of the circuit and reducing the current ormaking the bulb less bright. 1

b He used a bulb with a higher resistance, 1so it reduced the current a lot more, making the bulb less bright. 1


EXTENSION

J5


Homeworkmark schemeElectrical hazards

Sheet 6 of 7


1 A: no, one cell is the wrong way round or cells are back to back 1B: yes 1C: no, the wire is not connected to the lamp 1D: yes 1E: no, both wires are connected to the same end of the cell 1Accept equivalent answers.

2 a A fuse is an electrical safety device that melts if the current gets too high or there is a fault. 1

b Fuse wires have a high resistance. 1

c When a fuse wire melts, the electrical energy is transferred as heat energy 1and light energy. 1Answers can be in either order.

d If you get a shock from mains electricity, it can kill because it stops the heart beating. 1Underscores show answers; other text copied by pupils.

Total for Help 10

HELP


3 a Series circuit with cell, bulb and two unconnected wire endings. 1Wires (except the unconnected ends) drawn with a ruler. 1

b i The lamp would not light. 1ii The lamp would light. 1

c Left: good 1Right: faulty 1

d Parallel 1

4 a In a series circuit, both lamps would fail if one bulb breaks, but in a parallel circuit, one still works. 1

b If the fan stops working, so does the heater, preventing overheating. 1

c If one bulb fails, all the lamps go out, so you don’t know which one to replace or if one bulb comes loose, all the lamps go out. 1

Total for Core 10

CORE

J5


Homeworkmark schemeElectrical hazards (continued)

Sheet 7 of 7


5 a A, B, C and D 1

b C and D 1

c B, C and D 1

6 a

1One mark for the circuit redrawn with a switch at any point below the connection points for lamp E.

b

1One mark for the circuit redrawn with a switch in a wire running from between bulbs F and G to between bulbs G and H.


EXTENSION

H

E

G

F

H

E

G

F

Sheet 1 of 1

J


Transition quiz

1 Draw a line between each name and its correct symbol.

a battery or cell

b bulb or lamp

c switch

d wire

2 Look at these circuits. None of lamps will work. Circle where thefault is in each circuit.

Electrical circuits

Sheet 1 of 1

J


Transitionworksheet

1 Circuit X is shown below.

Redraw circuit X using these symbols.

2 Look at this circuit.a Which lamp or lamps will light

when you close switches B and C? ...................................... .

b Which switch or switches do you need to close to make lamp 1 light? ...................................... .

c Which lamps will light if you close only switch C? ...................................... .

Electrical circuits

� ��

circuit X

1

23

C

A

B

J


Test yourselfElectrical circuits

1 Complete this table.

2 Draw a circuit diagram for each circuit.

What name is given to each type of circuit?

...................................... circuit ...................................... circuit

3 Tick the lamps that will light up.

4 Complete these sentences by crossing out the wrong words.

a In a series circuit, as more lamps are added the lamps get brighter/get dimmer/stay the same brightnessand the current through each lamp increases/decreases/stays the same.

b In a parallel circuit, as more lamps are added the lamps get brighter/get dimmer/stay the same brightnessand the current through each lamp increases/decreases/stays the same.

Sheet 1 of 3

Symbol Component

cell

ammeter

� ��

J


Test yourselfElectrical circuits (continued)

5 Write in the missing reading for each ammeter opposite.

X .......................... Y ..........................

6 Bob has a battery-operated electric toothbrush which has stopped working. List three things for him to check to see what is wrong.

............................................................................................................................................

............................................................................................................................................

............................................................................................................................................

7 You are given a box of components to sort outwhich are working and which are broken.

a Draw a circuit diagram for a test circuit witha lamp, that you could use to test lamps,switches and connecting wires from the box.

b How would you use your circuit to find out if a lamp was faulty?

......................................................................................................................................................................

......................................................................................................................................................................

c How would you use your circuit to find out if a wire was faulty?

......................................................................................................................................................................

......................................................................................................................................................................

8 When a battery goes flat, what is used up? Circle the correct letter.

A energy B current C voltage D mass

9 Complete these sentences.

In a cell, ...................................... energy is converted to ...................................... energy.

In a lamp, ...................................... energy is converted to ...................................... energy

and ...................................... energy.

10 Look at the circuit opposite. Circle the correct letter(s) each time. Which lamp or lamps will light when:

a only switch A is closed? X Y Z

b only switch B is closed? X Y Z

c switches A and B are closed? X Y Z

Sheet 2 of 3

A1 A

0.5 A

2.5 A AAX

Y

A

A

Circuit diagram

B

X

A

Y

Z

J


Test yourselfElectrical circuits (continued)

11 Complete these sentences to explain how a fuse protects an electrical appliance. Choose from the words below to fill the gaps.

A fuse contains a piece of ...................................... which has a higher ......................................

than the rest of the circuit. If the current gets too ...................................... , the fuse will

....................................... This ...................................... the circuit so that the current

...................................... , protecting you from harm.

12 For a summer party, some friends are putting up a string of lights in the garden. What will happen if a bulb blows:

a if the lights are wired in series? ...........................................................................

b if the lights are wired in parallel? .......................................................................

13 Which of these arrangements will give the brightest light from the lamp? Circle the correct letter.

A B C D

14 Some children are given three different pieces of wire, A, B and C. They connect up a circuit like this. The table shows their results.

a Which piece of wire allows the current to pass through it easily? .............

b Which piece of wire has the highest resistance? .............

Sheet 3 of 3

� ��

� ��

� �� A B

C D

wires A, B, and Cconnected in here

Wire Lamp

A dim

B no light

C bright

resistance

mends wire high low stops

current breaksmelt

J


Test yourselfAnswersElectrical circuits

1 Complete this table.

2 Draw a circuit diagram for each circuit.

What name is given to each type of circuit?

...................................... circuit ...................................... circuit

3 Tick the lamps that will light up.

4 Complete these sentences by crossing out the wrong words.

a In a series circuit, as more lamps are added the lamps get brighter/get dimmer/stay the same brightnessand the current through each lamp increases/decreases/stays the same.

b In a parallel circuit, as more lamps are added the lamps get brighter/get dimmer/stay the same brightnessand the current through each lamp increases/decreases/stays the same.

Sheet 1 of 3

Symbol Component

cell

ammeter

� ��

✓

✓ ✓✓

✓ ✓

lamp or bulb

switch

battery

A

series parallel

J


Test yourselfAnswersElectrical circuits (continued)

5 Write in the missing reading for each ammeter opposite.

X .......................... Y ..........................

6 Bob has a battery-operated electric toothbrush which has stopped working. List three things for him to check to see what is wrong.

............................................................................................................................................

............................................................................................................................................

...............................................................................................................................................................................................................

7 You are given a box of components to sort out which are working and which are broken.

a Draw a circuit diagram for a test circuit with a lamp, that you could use to test lamps, switches and connecting wires from the box.

b How would you use your circuit to find out if a lamp was faulty?

............................................................................................................................................................................

............................................................................................................................................................................

c How would you use your circuit to find out if a wire was faulty?

............................................................................................................................................................................

............................................................................................................................................................................

8 When a battery goes flat, what is used up? Circle the correct letter.

A energy B current C voltage D mass

9 Complete these sentences.

In a cell, ...................................... energy is converted to ...................................... energy.

In a lamp, ...................................... energy is converted to ............................................ energy

and ............................................ energy.

10 Look at the circuit opposite. Circle the correct letter(s) each time. Which lamp or lamps will light when:

a only switch A is closed? X Y Z

b only switch B is closed? X Y Z

c switches A and B are closed? X Y Z

Sheet 2 of 3

A1 A

0.5 A

2.5 A AAX

Y

A

A

test components in this gap

Circuit diagram

B

X

A

Y

Z

2.5 A 1 A

Is the battery flat?

Are the contacts to the battery wet/dirty/corroded?

Are the contacts to the switch wet/dirty/corroded/Does the switch work?

Put the lamp in the gap to complete the circuit. If the lamps

light, it is working. If neither lamp lights, it is faulty.

Put the wire in the gap to complete the circuit. If the lamp

lights, the wire is working. If not, the wire is faulty.

chemical electrical

electrical light/heat

heat/light

J


Test yourselfAnswersElectrical circuits (continued)

11 Complete these sentences to explain how a fuse protects an electrical appliance. Choose from the words below to fill the gaps.

A fuse contains a piece of ...................................... which has a higher ..............................................

than the rest of the circuit. If the current gets too ...................................... , the fuse will

....................................... This ...................................... the circuit so that the current

...................................... , protecting you from harm.

12 For a summer party, some friends are putting up a string of lights in the garden. What will happen if a bulb blows:

a if the lights are wired in series? ...........................................................................

b if the lights are wired in parallel? .......................................................................

13 Which of these arrangements will give the brightest light from the lamp? Circle the correct letter.

A B C D

14 Some children are given three different pieces of wire, A, B and C. They connect up a circuit like this. The table shows their results.

a Which piece of wire allows the current to pass through it easily? .............

b Which piece of wire has the highest resistance? .............

Sheet 3 of 3

� ��

� ��

� �� A B

C D

wires A, B, and Cconnected in here

Wire Lamp

A dim

B no light

C bright

resistance

mends wire high low stops

current breaks

wire resistance

high

melt breaks

stops

They will all go out.

Only one will go out.

C

B

melt

J


End of unit testGreenElectrical circuits

1 Here are some circuits. For each one say whether or not the bulb will light when the switch is pressed. 2 marks

2 This table shows some symbols that are used to draw circuit diagrams. Some names and symbols are missing.

Write the missing names a and b and draw the missing symbols c and d. 4 marks

3 a What instrument is used to measure electric current? 1 mark

Look at the circuit diagrams.

b What is the current measured at X? 1 mark

c What is the current measured at Y? 1 mark

Sheet 1 of 4

a b

c d

� ��

� � � �

A4 A

Y8 A

A

A

A2 A

AX

a

b

resistor

c lamp (bulb)

d cell

A

J


End of unit testGreenElectrical circuits (continued)

4 a Here are two ways of wiring up a circuit with two lamps. Circuit A is called a series circuit.

What is the name given to circuit B? 1 mark

b One of the bulbs in this lamp has blown and needs replacing.i Which circuit, A or B,

shows how the bulbs are wired up? 1 mark

ii Explain how you decided this. 1 mark

5 Here are three circuits.

Which circuit is shown by this circuit diagram? 1 mark

Sheet 2 of 4

A B

C D

E

� � � � � � � �

� �

J



6 Look at the circuit diagram. We can use a marble model to represent this circuit.

a What in the model represents the current? 1 mark

b When the lamp transfers more energy, it gets brighter. What represents this in the model? 1 mark

Here is another circuit with two bulbs. It has the same current as before. It has a different battery.

In the marble model we represent the two lamps with two paddle wheels.

c In the model, what must we do to keep the ‘current’ (your answer to a) the same as when there is only one paddle wheel? 1 mark

d In the circuit with two lamps, more energy is being transferred by the battery. In the marble model with two paddle wheels, what must we do to transfer more energy? 1 mark

7 a What will happen to the fuse if the current through this iron is too high? 1 mark

b What happens to the flow of electricity in the circuit then? 1 mark

Sheet 3 of 4

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tubepaddlewheel

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marble pusher

tubepaddlewheels

J



8 Here is a test circuit for measuring the current through a piece of wire.

For wire A, the current is 0.2 A and the lamp is quite bright.

When wire B is tested, the current is 0.1 A and the lamp is dimmer.

Which wire, A or B, has the higher resistance to the flow of electricity? 1 mark

9 a Look at the batteries inthe diagram. Which battery stores the most energy?

1 mark

b The lamps in this circuit work on 1.5 V each. Write the letter of the battery that will light the lamps in this circuit. 1 mark

c Pippa has made the parallel circuit shown in b above. As she added each lamp to the circuit, she measured the current at point P using an ammeter. The table shows her results.

What was the ammeter reading when she added the third lamp? 1 mark

d Pippa then built this series circuit. The table shows her results as she added each lamp.i Why does the ammeter reading fall as

each lamp is added? 1 markii What is the effect on the lamps as each

one is added? 1 mark

Sheet 4 of 4

test wire A testwire B

� �

� �

1 .5V

�

�9V�

X Y Z

1.5V

P

Number Ammeterof lamps reading in A

1 0.48

2 0.96

3


1 0.48

2 0.33

3 0.26

A

J


End of unit testRedElectrical circuits

1 Here are three circuits.

Which circuit is shown by the circuit diagram opposite? 1 mark

2 Here are diagrams of four circuits. Two diagrams show the same circuit. Write the letters of these two circuits. 1 mark

3 a What will happen to the fuse if the current through this iron is too high? 1 mark

b What happens to the flow of electricity in the circuit then? 1 mark

4 a What instrument is used to measure electric current? 1 mark

Look at the circuit diagrams.

b What is the current measured at X? 1 mark

c What is the current measured at Y? 1 mark

Sheet 1 of 5

A B

C

� � � � � � � �

� �

D E F G

A4 A

Y8 A

A

A

A2 A

AX

J


End of unit testRedElectrical circuits (continued)

5 Here are two ways of wiring up a circuit with two lamps.

One of the bulbs in the lamp below has blown and needs replacing.

a Which circuit, A or B, shows how the bulbs are wired up? 1 mark

b Explain how you decided this. 1 mark

6 This test circuit is for measuring the current through a lamp.

Two lamps are tested. For lamp P the current is 0.2 A. For lamp Q the current is 0.1 A.

Which lamp, P or Q, has the higher resistance to the flow of electricity? 1 mark

7 Anna has two torches, R and S. Each torch needs three cells to make the lamp light. Torch R has one new cell and two older cells. Torch S has three new cells. Anna puts a new bulb in each torch.

a Is the energy used by torch R in 10 minutes the same, more than or less than the energy used by torch S in 10 minutes? 1 mark

b Anna replaces a second older cell in torch R. What will happen to the current in torch R? 1 mark

c Anna is choosing a new battery for a circuit she is making with several lamps in it. Which battery below would make the lamps brighter? 1 mark

Sheet 2 of 5

A B

A

test

�

9V�

T U

1.5V

J



8 Look at the circuit diagram. We can use a marble model to represent this circuit.

a What in the model represents the current? 1 mark

b When the lamp transfers more energy, it gets brighter. What represents this in the model? 1 mark

Here is another circuit with two bulbs. It has the same current as before. It has a different battery.

In the marble model we represent the two lamps with two paddle wheels.

c In the model, what must we do to keep the ‘current’ (your answer to a) the same as when there is only one paddle wheel? 1 mark

d In the circuit with two lamps, more energy is being transferred by the battery. In the marble model with two paddle wheels, what must we do to transfer more energy? 1 mark

Sheet 3 of 5

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J



9 a If you touch something hot, the nerve cells in your fingers detect the heat and send a message through the nerves to the brain. How do the messages travel? 1 mark

b Peter was told by his dad not to fly his kite near overhead electric power lines. Explain what might happen if he does. 1 mark

c Electric fences have a power supply of 12 V. They are often walked into by animals or humans. Why are electric fences less dangerous than overhead power lines? 1 mark

10 a Pippa has made this parallel circuit.

As she added each lamp to the circuit, she measured the current at point P using an ammeter. The table shows her results.

What was the ammeter reading when she added the third lamp? 1 mark

b Pippa then built this series circuit.

The table shows her results as she adds each lamp.i Why does the ammeter reading fall

as each lamp is added? 1 markii What is the effect on the lamps as

each one is added? 1 mark

Sheet 4 of 5

P


1 0.48

2 0.96

3


1 0.48

2 0.33

3 0.26

A

J



...continued

c Luigi Galvani was dissecting a frog. He touched his metal scalpel to a nerve in the frog’s leg, and the leg kicked. Galvani guessed that his scalpel had sent an electric pulse through the frog’s nerve. To test this idea, he hung frogs’ legs from brass hooks on an iron railing in his garden. The legs kicked only once, when Galvani first touched the brass hooks to the railing.

Galvani thought the electricity came from the frog muscles, but his friend Volta was not so sure.

Volta thought about Galvani’s experiment. He replaced the frogs’ legs with cloth soaked in salty water. He tried the experiment with many different metals, and found the most electricity came when he used silver and zinc. He made a pile from several layers of silver and zinc plates, with wet cardboard between. He found he got a continuous flow of electricity from this.

i How did Volta show that the electricity did not come from the frog muscles? 1 mark

ii What was it that Volta had invented with his pile of discs? 1 mark

Sheet 5 of 5

J


End of unit testmark schemeElectrical circuits

Sheet 1 of 1

Green (NC Tier 2–5)

Scores in the range of: NC Level

4–8 2

9–13 3

14–18 4

19–25 5

Question Answer Mark Level

1 a No 2 2

b No

c Yes

d YesAll correct: 2 marks; two or three correct: 1 mark; one or none correct: 0 marks.

2 a Switch 1 3

b Ammeter 1 3

c 1 3

d 1 3

3 a Ammeter 1 4

b 2 A 1 4

c 4 A 1 4

4 a Parallel circuit 1 2

b i B 1 3ii The other bulbs are still on. In a series circuit, all the bulbs would

go out. 1 4

5 D 1 3

6 a Marbles flowing 1 4

b The paddle wheel turning faster 1 4

c Turn the handle faster or harder 1 5

d Turn the handle faster or harder 1 5

7 a It will blow or melt. 1 4

b The circuit is broken or the flow of electricity stops. 1 4

8 B 1 4

9 a X 1 3

b X 1 3

c 1.44 A 1 4

d i There is more resistance or the current is lowered by the lamps. 1 4ii They get dimmer. 1 4

J


End of unit testmark schemeElectrical circuits

Sheet 1 of 1

Red (NC Tier 3–6)

Scores in the range of: NC Level

5–9 3

10–14 4

15–18 5

19–25 6

Question Answer Mark Level

1 B 1 3

2 D and G 1 3

3 a It will blow or melt. 1 4

b The circuit is broken or the flow of electricity stops. 1 4

4 a Ammeter 1 4

b 2 A 1 4

c 4 A 1 4

5 a B 1 3

b The other bulbs are still on. In a series circuit like A, all the bulbs would go out. 1 4

6 Q 1 5

7 a Less than 1 6

b It increases 1 6

c T 1 5

8 a Marbles flowing 1 4

b The paddle wheel turning faster 1 4

c Turn the handle faster or harder 1 5

d Turn the handle faster or harder 1 5

9 a As electrical signals or electric current 1 5

b If the kite touches the power line, he could get a serious electric shock which might kill him or stop his heart. 1 5

c The overhead power lines have a much higher power supply or carry more energy or will give a more powerful electric shock. Accept equivalent answers or suitable alternatives. 1 5

10a 1.44 A 1 4

b i There is more resistance or the current is slowed down by the lamps. 1 4ii They get dimmer. 1 4

c i He replaced frogs’ legs with cloth soaked in salty water. 1 5ii A battery or cell 1 5

Sheet 1 of 1

J


Pupil check listElectrical circuits

Learning outcomes I can do I can do I need tothis very this quite do more well well work on this

I can recognise and describe examples of energy transfers in electrical circuits.

I can recognise and name the symbols for all the electrical components.

I can draw circuit diagrams using the appropriate symbols.

I can describe the difference between a cell and a battery.

I can use ideas about how water flows in pipes to explain how current flows around a circuit.

I can connect and use an ammeter safely.

I can describe how current changes when the number of cells or bulbs in a circuit changes.

I can recognise and describe examples of series and parallel circuits.

I can use ideas about water flow to explain how current flows in parallel and series circuits.

I can give one advantage of a series circuit and a parallel circuit.

I can use my ideas of how current flows around a circuit to predict the ammeter readings in parallel and series circuits.

I can use a model of electricity to explain ideas about electrical circuits.

I can describe why models are useful but may have limitations.

I can give an example of a hazard associated with electricity.

I can describe how to find faults in a circuit and make it work again.

I can describe the role of a fuse in an electrical circuit.

Sheet 1 of 1

J


Glossary

Word

A

ammeter

amps

battery

cell

chemical energy

complete circuit

current

electrical energy

energy

fault

filament R

fuse

model

parallel circuit

resistance

ring main

series circuit

V

voltage

volts

Definition

Energy makes things work. When anything happens,energy is transferred.

An object that changes chemical energy into electricalenergy.

Energy carried by electricity.

The energy a cell stores is measured in volts.

How much energy the electricity is carrying.

The short way of writing volts.

Stores chemical energy. More than one cell connectedtogether in an electrical circuit.

Electricity flowing around the circuit.

A device that measures the current in an electrical circuit.

Current is measured in amps.

The short way of writing amps.

How much something slows down the electric currentpassing through it. A thin wire slows down the currentmore than a thick wire, so it has a higher resistance.

A circuit in which everything is in one loop.

A circuit with more than one loop.

A very thin wire inside a light bulb, that glows whenthe current passes through it. R

An idea or picture made up by a scientist to show asituation that cannot be seen. A model helps scientiststhink through explanations.

Something that stops an electrical circuit from working.

The electrical circuit in a house. It is a parallel circuit.

A safety device for electrical circuits. The fuse has avery thin wire which melts if the current gets too high,and breaks the circuit.

Cells and lamps or other devices joined by wires tomake a closed loop.

Energy stored in a material, which will be given out ina chemical reaction.

Electrical circuits

Sheet 1 of 1

J


Key wordsElectrical circuits

A

ammeter

amps

battery

cell

chemical energy

complete circuit

current

electrical energy

energy

fault

filament R

fuse

model

parallel circuit

resistance

ring main

series circuit

V

voltage

volts

J Key words

�


Electrical circuits

A

ammeter

amps

battery

cell

chemical energy

complete circuit

current

electrical energy

energy

fault

filament R

fuse

model

parallel circuit

resistance

ring main

series circuit

V

voltage

volts

J1 Electrical energyGreena A cell.b Electrical energy.c Yes1 Chemical energy from the cell is transferred

into the circuit as electrical energy. More thanone cell connected together makes a battery.In a circuit, you must connect the positive end ofeach cell to the negative end of the next one.

2 a threeb threec Switches closed Lamps lit

A, B, C 1, 2, 3none noneA, C 2A, B 2A 2

Reda A cell.b Battery → electrical energy → stereo →

sound energy1 a 9 V

b 9 V2 a three

b threec Switches closed Lamps lit

A, B, C 1, 2, 3none noneA, C 2A, B 2A 2

3 Volta invented the battery. He made the firstcell by putting two metal discs in a saltsolution. He made the battery by piling upalternate metal discs separated by paper soakedin salt solution.

J2 Current affairsGreena cellb wiresc lampd in seriese ampsf Laurag Laura1 There is a current in the circuit. We measure

current using an ammeter. Current ismeasured in amps. The current is the samebefore and after a lamp.

2 The current is the same any place in the circuit.3 By wires.

Reda cellb lamp

c the samed Laurae increases1 Correct complete circuit with cell, lamp and

ammeter in series.2 amps3 a

b The current might be too high for the lampand it could burn out.

4 The model is not a good one. If a radiator leaks, the heating would continue. But if thelamp burns out, the circuit would stopcompletely.

J3 Different circuitsGreena Ab Bc Bd 0.1 Ae 0.4 A at P, 0.2 A at Q, 0.2 A at R.1 resistance2 Series circuit Parallel circuit

The lamps are dimmer. The lamps are brighter.The current is the The current issame at all points in shared between thethe circuit. loops of the circuit.

3 Less current would flow in the circuit and thelamp would be dimmer.

Reda Longer pencil lead gave more resistance; shorter

gave less.b 0.1 Ac 0.2 Ad parallele 0.1 Af 0.4 A at P, 0.2 A at Q, 0.2 A at R1 Resistance is how hard it is for current to flow

in a circuit. In dimmer switches, the amount ofresistance can be made to change. The moreresistance in the switch, the less current flowsand the dimmer the lamp. The less resistance,the more current flows and the brighter thelamp.

2 Less current would flow in the circuit and thelamp would be dimmer.

J Book answersElectrical circuits


Current(amps)

00

Number of cells4321

1.00

2.00

3.00

4.00

3 Series circuits Parallel circuitsdimmer lamps brighter lampsonly one loop two or more loopsless current more current

4

J4 Models of electricityGreena i Railway track.

ii The power station.iii The mine.iv Coal

b Increasedc No, the current stops flowing.d i Energy is represented by the matches.

ii The circuit is the white circle path alongwhich the pupils walk.

iii The walking pupils.e Appropriate drawing where the matches are

green, the circle is pink, the pupils are yellowand Mrs Fuller is blue.

1 a Jackie’s diagram does not show what happensin the circuit. The circuit is not complete.

b Lester’s diagram shows a complete circuitbut does not show where the energy wasused.

Reda i Railway track.

ii The power station.iii The mine.iv Coal

b Increasec Greater resistance.d It is a good model; but it doesn’t allow for all

differences, as if the trucks should be derailed.e The current stops flowing. No, the electricity

doesn’t spill out.f Appropriate drawing where the matches are

green, the circle is pink, the pupils are yellowand Mrs Fuller is blue.

g Yes, it helps as each part of an electrical circuithas a matching piece of the model.

h An ammeter in the model could be a pupil witha stopwatch measuring how quickly the pupilsmove. The ammeter would be in the path of thepupils.

i One example could be that resistance is shownby having a hump, mound or set of stairs in thepath that the pupils would have to climb up,which would slow down the pupils’ rate ofmovement, the current flow. Other appropriateexamples might be acceptable.

1 Individual answers with reasons.2 Individual answers.

J5 Electrical hazardsGreena The cells are the wrong way round.1 More lamps can be used because the current

flowing is shared in the loops of the parallelcircuit. If one part of the parallel circuit isbroken, the other loop will continue to work.

2

3 All plugs in appliances have fuses. If the currentin an appliance gets too high or there is a faultin the circuit, the fuse melts, the circuit isbroken and the current stops flowing. This cankeep you from getting an electric shock. Itcould also stop the wires from getting too hotand causing a fire.

Red1 Various faults possible such as: cells in the

wrong way round, switch broken, lamp burnedout, rusted contact with cell.

2

3 More lamps can be used because the currentflowing is shared in the loops of the parallelcircuit. If one part of the parallel circuit isbroken, the other loop will continue to work.

4 The current increases.

J Book answers


1801

Davy madelight usingelectricity

1878/79

Swan & Edisonfound thin carbon

filament whichwould last

1911

carbonfilament

replaced bytungsten

1913

filamentmadecoiled

Documents

Electrical circuits Unit guide - Physicslocker 1/FILES/Unit J.pdfElectrical energy circuits. electricity