# 01Build and model electrical loops

Ec01TA of the Electrical loops topic
• ## 01 Selecting and developing activitiesEc01TAnugget01 Suggestions

### Based on the Physics Narrative and the Teaching and Learning Issues

Ideas to emphasise here

• the complete loop, working all together
• something moving round, everywhere in the loop
• build on the idea that something is used up as the battery flattens
• relate your model of something moving around the loop to actions in adding elements to a loop
• connect toolkits for thinking with physical experiences with circuits

Teacher Tip: Work through the Physics Narrative to find these lines of thinking worked out and then look in the Teaching Approaches for some examples of activities.

Strategies for supporting learning

• draw out, and challenge wrong track thinking
• link practical experiences to developing descriptions
• let children use pictures, diagrams, physical actions and physical models as well as words to express themselves
• develop a toolkit to support children's reasoning about circuits
• allow children to question and explore different explanations
• retain a focus on whole loops
• link practical experiences to developing descriptions
• relate children's pictures, diagrams, physical actions and physical models to what happens when real circuits are built
• encourage children to reason about circuits, making and testing predictions
• use large drawings of circuits to help relate the physical to the drawings

Teacher Tip: These are all related to findings about children's ideas from research. The teaching activities will provide some suggestions. So will colleagues, near and far.

Avoid these

• not challenging imprecise language, reasoning, diagramming
• using sequential models, such as donation models
• electrical energy
• telling long stories about electrons in wires as just how it is
• avoid sequential reasoning: first it leaves the battery, then it...
• just stating what should have happened
• relating ad-hoc rules as just how it is
• not conflating homely analogies with ways of reasoning that can make predictions

Teacher Tip: These difficulties are distilled from: the research findings; the practice of well-connected teachers with expertise; issues intrinsic to representing the physics well.

• ## 02 A sequence to develop ideas about simple electrical loopsEc01TAnugget02 Sequence

### Based on the Physics Narrative and the Teaching and Learning Issues

Meeting reality: valuable experiences

Electrical loops are rather pervasive, as they are such a convenient way of getting jobs done. That's because electrical loops are good at powering things, and because that power can be controlled. So it makes some sense to start off by looking at the jobs that electrical loops can do for us in the lived in world, and to move from there to creating and varying loops for themselves.

There is some practical difficulty in investigating mains electricity: not helped by the fact that many mains plugs and sockets have three terminals. Therefore we'd suggest not trying to make too careful a link between these early explorations and later work with making loops. ( There is a clear connection, but it's not simple – you can see more in the SPT: Electricity and energy topic.)

There is however plenty of simple practical activity that can be used to get children off on the right track in thinking about electrical loops. As much of this involves making things there are opportunities for strong links with other parts of the curriculum.

• identify sources of electrical power
• make and vary electrical loops
• choose materials for making electrical loops

A sequence for developing the idea

This is a rather short sequence focusing on electrical loops, once we have established the pervasiveness of electricity.

We think it's very helpful to think in terms of loops, as all electrical circuits are made of loops. Finding the loop, breaking the loop, making the loop and choosing what to put in the loop are all useful activities they get children thinking along the right lines. Each loop needs thinking of as a whole if you are to understand it and that's a further advantage of thinking about electrical circuits in terms of complete loops.

Teacher Tip: The ideas are developed in the Physics Narrative.

A survey activity, identifying electrical appliances in the everyday world.

Writing: a day without the electrical loop

A story writing activity: imagine a day in which there was no electricity available to power devices, and the consequences.

Tracing out loops in battery-powered devices

Here children can study simple battery-powered objects where they can rather easily notice the electrical loop. They should be encouraged to make a variety of records of what they notice.

Making loops

Here children make simple electrical loops, taking pleasure in making something simple that works.

Choosing materials for making loops?

Some materials are better for making electrical loops than others: here children can explore what they might use to complete loops.

Breaking loops

This activity introduces simple switches, and puts them to use.

Putting loops to work

Here there are a simple series of challenges: to build circuits to solve problems. In each case the solution is a single electrical loop.

Varying loops

Children are set the task of systematically varying what is in an electrical loop and then making a record of what they notice. You can seek out simple patterns, but full-blooded theorising is not expected.

Messages from research and practice: specific tripwires for this idea

Keep in mind a clear idea of where children's understanding of electric circuits is expected to be at the end of the next step in studying circuits, and not this one. Here you do not have to introduce any reasoning about what happens inside the wires, but it is useful for you to have in mind in order to know what children should be exploring, and in order to avoid seeding unhelpful Ways of thinking about electrical loops.

This is a summary of the right tracks down which children can go, and also of the wrong lines which their thinking can follow. In this introductory phenomena- based work, it's a good idea to have these in mind even if they're not explicitly introduced the children.

Where do the charges come from?

The battery does provide the active element in an electrical loop, but the wires or other conductors already contain electrical charges free to move. It is possible to introduce batteries in such a way that you get children thinking that everything starts in the battery: this is not true. in particular when you trace out circuits, because the important point is that it is a complete electrical loop, it's helpful to start at different points around the loop – and not always to start the battery.

Conductors and insulators

Electrical loops are made of electrically conducting material – or conductors. Deciding what is good to put in such a circuit is a matter of choosing a material. However, the distinction between conductors and insulators is not clear-cut.

Each complete electrical loop acts as a whole: you cannot think effectively about each of the parts independently.

Do the charges move instantly?

The charges move altogether

The resistance sets the current for the whole circuit

What happens in one part of the circuit nearly instantaneously affects what happens in another part of the circuit. It is really unhelpful to argue about electrical circuits as a story-like process, where what happens in one location sets up a message which is carried around in some sense and then later affects what happens in another part of the circuit. This is really misleading thinking.

In the end, you'd like children to appeal to reason confidently about electric circuits. that mean having a good mental model of what is happening in electrical circuits, as opposed to a series of vaguely appreciated analogies.

In thinking about conversations that have and explorations to promote, it's really helpful to have in mind a manipulable model that children might be working towards: not that they'll reached that model now, simply that you can set them off on the right path.

Varying what you place in an electrical loop affects everything in the loop: this is therefore complex reasoning, not advised for the majority of children of this age. At this stage these are simply to raise your awareness of issues that will arise in the future, so that you can set children off along the right path.

Varying what's in the loop

Teacher Tip: These challenges and some suggestions for working with them are more fully explained in the Teaching and Learning Issues.

Representing and reasoning: doing physics

Children will be exploring the phenomena associated with electrical loops. They will not be theorising about what happens inside the wires, at least that's not a formal requirement. However, in your discussions with children, it will be useful to have in mind a way of thinking about electrical circuits which can support such discussions.

So most of the physics narrative here is for the benefit of teachers, rather than the benefit of children: it is to provide you with the background support the conversations in the classroom, rather than provide material which might be developed with children in the classroom.

Electric current: a flow of charges

A simple loop: current the same everywhere

When an electrical circuit is complete and functioning there is a flow of charges everywhere in that loop: the charges originate in the loop and set moving by the battery or power supply. Such a flow of charges is called an electrical current.

Electric current: a flow of charges

A simple loop: current the same everywhere

Adding extra elements to the electrical loop (more batteries or more bulbs) affects this flow of charges. adding more batteries increases the flow and adding more bulbs reduces flow, because it increases electrical resistance.

A good way of thinking about electrical loops. is to compare them with mechanical loops.

Teacher Tip: For children, it's all about the phenomena, not the details of what happens inside the wire.

• use physical artefacts, not circuit diagrams
• encourage thinking in loops

Teacher Tip: Find out more from the Physics Narrative.

### Finding everyday examples

What the activity is for

In this activity children can come to see the pervasiveness of electrical circuits everywhere in their lived in world.

we suggest that children are encouraged to notice both battery powered devices and mains powered devices.

What to prepare

• A suitable frame for recording the devices

What happens during this activity

Introduce a few devices by means of examples, preferably having to hand and suggesting an approximate set of criteria by which you might decide whether they are or are not powered by electricity.

Children might then be asked simply to look in their own home or around the school for more devices and might also apply number of different categories to decide on the function of the device.

Alternatively you might settle collectively on a number of devices and then find instances of their use(perhaps also recording the duration of and frequency of their use during a week).

There are a number of different strategies that you could adopt to suggest how much we've come to rely on the existence of the electrical loop.
• ## 04 Writing: a day without the electrical loopEc01TAnugget04 Activity

### One day, we lost the ability to...

What the activity is for

In this activity children are asked to write an imaginative story in such a way that it helps them to see how much we have come to rely on electrical loops.

What to prepare

• a writing frame, perhaps the start to a story

What happens during this activity

You might have a story in your library that involves electrical circuits, or a poem, or any other starter. The idea here is to engage in some counterfactual thinking, in the context of writing fiction, to enable children to come to see how much they rely on electrical loops.
• ## 05 Tracing out loops in battery-powered devicesEc01TAnugget05 Activity

### Finding loops in battery-powered devices

What the activity is for

Children should identify complete loops in battery-powered devices and devise their own records of that loop, using their own diagrams writing or other notation.

What to prepare

• a collection of small torches, or other battery-powered devices (often found constructed using translucent plastic), where it is easy to make out a complete electrical loop

What happens during this activity

Introduce the idea of an electrical loop, perhaps using the rope loop model. Emphasise that what happens in one place in the loop affects what happens in another place in the loop – for example changes in the battery (running down) allow all drive changes somewhere else (motor turns or a lamp glows).

Then produce your supply of small translucent battery-powered objects and encourage the children to identify the loops and to communicate their findings, using their own diagrams and words.

• ## 06 Making loopsEc01TAnugget06 Activity

### Using simple electric circuits

This is a design and make activity through which you can explore the idea of a complete circuit with the children and help them to build a circuit using the available laboratory equipment.

What the activity is for

• To capture interest.
• To review the idea of a complete circuit.
• To engage children in designing and making circuits using appropriate laboratory equipment.
• To encourage children to talk and think about simple electric circuits.

What to prepare

• batteries, buzzers and bells
• connecting wires
• copper wire, copper strip, stiff card, plastic foam or clear tape

What happens during this activity

Start by demonstrating with a simple circuit containing a battery and a buzzer or bell that a complete circuit is needed for a buzz or ring. Then explain that the children are going to use this simple principle to design and make one of three devices:

• A burglar alarm for the classroom door: open the door and the bell rings.
• A pressure pad alarm: stand on the mat and the bell rings (or sit on the chair and the bell rings).
• A steady hand tester: touch the wire with the loop and the bell rings.

Divide the children up into teams of three or four and allocate a device to each team. Insist that the teams spend 10 minutes in talking through and drawing out their ideas before starting to work with the equipment. Equipment and materials should be set out so that the teams can collect whatever items they think will be useful. Be prepared for requests for additional items!

Allow plenty of time at the end of the session for each team to:

• Describe their invention.
• Explain how the device works.

To add to the sense of occasion, you might get some children to invite another member of staff into the lesson to try out the alarmed chair!

Experience has shown that the children really enjoy this activity and that it provides an excellent opportunity for talking around basic electric circuit ideas. Be prepared for children insisting that their door alarm is left in place, and then showing their friends from other classes how it works at break time!

• ## 07 Choosing materials for making loops?Ec01TAnugget07 Activity

### Finding materials which conduct more or less well

What the activity is for

Here the aim is to introduce the idea that materials are better or worse for making electrical loops, and that we might usefully remember which are which by labelling these materials. those which are good for making loops we might call conductors and those which are not so good we might call insulators.

What to prepare

• a set of simple test circuits containing a bulb and a battery, as well as the terminals in which to place the test item
• a collection of suitable test materials

What happens during this activity

Introduce the activity as a way of deciding which materials might be good for building electrical loops. If the bulb comes on then an material might well be put in the more suitable collection, otherwise the material should be placed in the less suitable collection.

Some discussion about the kinds of materials you have in each block is likely to reveal that many of those label conductors are metals: take care though – perhaps not all.

Teacher Tip: Try to avoid the suggestion that the distinction between in insulators and conductors is absolute.

• ## 08 Breaking loopsEc01TAnugget08 Activity

### On-Off Switches

What the activity is for

Simple make or break switches complete or break single loops. Here children investigate the simple on-off switches, devising a number of different ways of making and breaking loops.

What to prepare

• a large complete electrical loop
• a collection of pieces of conductor to make switches
• batteries, bulbs, wires

What happens during this activity

Show a large complete loop, containing a battery and a bulb, and then ask how to turn the bulb on and off. Extend the question to include turning the bulb on or off from a large number of different locations around the loop. Here you can emphasise the loop as a complete system, because what happens at one point affects the entire loop.

The children should have a go at devising their own switches, aiming both for elegant solutions and for intriguing solutions, as well as simple reliable switches. Having to hand a few large switches (ensure that these are on-off switches) of a variety of designs will encourage the children to adopt different approaches.
• ## 09 Putting loops to workEc01TAnugget09 Activity

### Designing and building electrical loops

What the activity is for

Here, children construct a variety of circuits that all contain an on-off switch. The activity builds on their understanding of how electrical loops work and the role of switches within a loop.

The aim is that children are able to design and construct a variety of circuits incorporating a switch for particular purposes.

What to prepare

• a complete electrical loop
• a collection of pieces of conductor to make switches
• batteries, bulbs, wires

What happens during this activity

Set the children some design challenges, such as the following:

1. build a circuit which includes a switch that will turn a light off when a door opens.
2. build a circuit which includes a switch that will turn a light on when a door opens.
3. build a circuit which includes a switch that is operated by a magnet.
4. build a circuit which includes a switch that is operated by a rising water level.
5. build a circuit which includes a switch that sits inside a pencil case and will turn on an alarm in the pencil case if it is stolen.

In each case you might contextualise the challenge by providing a simple situation in which this can switch will be useful. the solution in each case will be a single loop containing a switch or switches. There is no need to have branches on the loop, or multiple loops.

Children should be encouraged to document their solutions in their own style.

You might introduce circuit diagrams here as a means to easily understand each others solutions.

Teacher Tip: Do encourage students to make their own switches. Do your best to discourage them from creating a short circuit to turn a bulb off as it will quickly flatten the battery and could be dangerous. As a real-life engineering solution, the short-circuit is not acceptable!

• ## 10 Varying loopsEc01TAnugget10 Activity

### What happens when bulbs are added?

What the activity is for

Through working with physical loops, the children establish that when an extra bulb is added to a simple electric circuit, the bulb gets dimmer.

When an extra battery is added to a simple electric circuit, the bulb gets brighter; or the buzzer/bell sounds louder; or the motor turns more quickly.

They are then encouraged to think about their observations.

What to prepare

• batteries
• bulbs/buzzers/bells/motors

What happens during this activity

The children work in small groups to observe what happens with one, two and possibly three bulbs in a loop.

Then children are encouraged to talk and think about the electrical loop to describe what they have found with the various electric circuits.

The children first of all work in pairs to talk through their ideas to explain why the bulbs are dimmer and the current smaller when a second bulb is added. Pairs then report back in during class discussion.

### What happens on adding a battery?

What happens during this activity

The children work in pairs to explore a circuit containing a bulb and then a circuit with a buzzer/bell/motor with one, two and possibly three batteries (you should check beforehand that the bulbs will survive three batteries) and observe what happens.

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