Circuit training

What did this lesson have that made it an Ofsted winner? John Springer presents a science session that explored how switches work. Illustration by Pat McCarthy

Subject: Science

Class: Year 4

Whole class splitting into groups with Learning Assistant support

Switches have made a curriculum leap. Once part of the junior curriculum, they are now in key stage 1 - Sc4 1c "How a switch can be used to break a circuit". In the lesson described here, teacher questioning showed that the children were not secure in their understanding of conductors and insulators, but they recalled using switches for a model lighthouse in the infants.

This lesson arose from work in the QCA Scheme of Work unit 4F, "Circuits and conductors". The teacher was uncertain about the children's previous learning, both because they had done unit 2F, "Using electricity", two years before, and because curriculum change meant that they might not have had prior experience of switches.

Children were asked to collect information in groups and pool their ideas, but questions to the class were answered by individual pupils.

There were some unpredicted moments. When asked about switches, the children announced that there were "push to make" and "push to break" types - information from their DT lessons. The teacher had not thought of the latter (which switch off the inside light when you close the car or the fridge door). And the lesson was sidetracked for a while to tackle the business of wet hands and bathroom switches.

Elements that made the lesson a success

* The learning support assistant had been carefully briefed and had practised the activity.

* The activity was set in a context - the children were asked about switches and what they did before they went about making their own.

* The teacher introduced the idea that using a switch didn't just mean that the circuit was broken, but also that the air in the gap prevented the electricity flowing. He referred to previous work (unit 4C, "Keeping warm") and emphasised that an insulator - whether of heat, sound or electricity, - slowed down or stopped movement.

* The children responded with enthusiasm, predicting results and recording them on a prepared table.

* The teacher adapted to the unexpected - not just the children's previous knowledge but also the switches that children built that didn't fit the expected model of two pins and a paper clip swinging like a door. Some made "double doors", and one used a chain of paper clips. He accepted all ideas, gently challenging those that did not fit the usual pattern.

* The extension work placed the learning back in an everyday context. Questions such as "Why are switches made of insulating material?", "Why are electric wires covered in plastic?" reminded the children of the everyday role of insulators.

* At every possible point, the teacher reinforced ideas of safety when using electricity.

* Finally, the teacher brought the whole lesson back to the original knowledge trawl. Some of the "we think" statements became "we know" - confirming for the children, and the watching inspector, what they had learned.

LESSON PLAN

Tuesday 10.45 to 11.55am

QCA unit 4F: Circuits and conductors

Learning outcomes

* To understand that some materials are conductors and some are insulators.

* To understand that air is an insulator - and so making a gap will "break" a circuit and stop electricity flowing.

* To understand that switches can be used "to make electrical devices work".

Focus questions

* Where do we find switches?

* What do they do?

* How do they work?

* How can we use a switch to make a circuit complete and make electrical devices work?

Safety

It is essential to explain at the beginning and end of the lesson that battery power is safe but mains power is not.

Equipment

Batteries, battery boxes, bulbs to match the batteries, prepared leads with crocodile clips, a range of practical objects to test for conductivity, small wood blocks, paper clips and drawing pins for home-made switches. A range of switches for possible extension.

Learning assistant to support all groups, but especially the Dragons table.

LESSON DEVELOPMENT

Questioning: Pupils work in small groups to remember all that they know about switches. List answers on whiteboard. Divide into "what we know" and "what we think". 10 minutes.

Demonstration: How to make an open circuit and how to decide whether different objects conduct or insulate when put into the circuit. 5 minutes.

Presentation of results: Ask children, working in pairs, to make an open circuit, predict what they think will happen, put objects into the circuit and record the outcome in a four-column table (object, prediction, conductor, insulator). Warn pupils not to use watches or objects powered by electricity. 10-15 minutes.

Assessment: Probe pupils on their understanding of why the electricity didn't flow when the circuit was open. Conclusion that air is an insulator - and should be added in the "insulators" column. 10 minutes.

Discussion: Use the information collected to classify switches into those you hold, like doorbells and tools, and those you leave on, like lights and TVs. 5minutes.

Activity to model switches, pin the paper clips to the wood blocks, opening and closing them like doors. (You could also bend a clip upwards and press on it like a doorbell switch). Draw our models. 15-20 minutes.

Extension Show a range of switches. 5 minutes.

Finish with a safety warning - including the information that very powerful electricity, like that in electric train and power lines, can overcome the air's insulation and jump across gaps.

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