– construct a test circuit

– represent a functioning circuit

TEACHER BACKGROUND INFORMATION:

* Read Teacher background information: It’s Electrifying page 12 – 16

LESSON:

1. Review students’ exploration of battery-operated devices from the previous lesson – focus on their ideas of how a torch works. Review the class science chat-board – discuss some of the ideas/questions that have been contributed.

2. Explain that students will be working in cooperative teams to explore how they can light up a light bulb using a battery and one or two wires. Show the resources available for each team.

3. Introduce the Predict, Reason, Observe, Explain (PROE) strategy using the enlarged copy of the ‘PROE record: Lighting up my life’ (Resource sheet 1) in class science journal. Explain each PROE step – See notes on right.

4. Form teams, allocate roles, managers collect team equipment.

5. Each team member completes the ‘P’ and ‘R’ sections of the resource sheet – paste into his or her science journal. Ask students to share their predictions and reasons with their team and the class.

6. Cooperative learning teams construct and test circuits. Complete the ‘O’ and ‘E’ sections of the sheet using writing and drawings. See the following SAFETY notes.

·       Explain that when using low-voltage batteries, for example, 9V or less, in their investigation, it is safe for students to touch base wire because there is only a small amount of electrical energy coming from the battery. Any bare wires carrying mains electricity or high voltage (electrical energy) are extremely dangerous.

·       Connecting a wire from one end of the battery terminal directly to the other terminal will cause the wire to become very hot (and flatten the battery). Explain that students should always have a device, for example, a light bulb, between the wires that goes from one terminal of the battery to the other terminal. To complete a functioning circuit, they will need to make connections with both (positive and negative) terminals of the battery and the two points on the light bulb.

 7. Ask questions during investigation,

* What happens if you put the wire on other parts of the light bulb?

* What happens if you put the wire on other parts of the battery?

* Which parts of the light bulb/battery seem to be the same?

* Which parts of the light bulb/battery seem to be different?

8. Students continue to record predictions in the ‘O’ and ‘E’ boxes on the sheet in their science journal.

9. If teams quickly complete a functional circuit using two wires? Challenge them – create a functional circuit using one wire (which they can do if they connect the remaining connection point on the light bulb directly with the remaining connection point on the battery).

10. Complete investigation, managers return equipment. Lead a class discussion and share their ‘O’ and ‘E’. Attempt to reconcile any differences students may have experienced compared to their predictions and former reasoning.

11. Team speakers create a drawing on the board to show how their team made the light bulb light up and also a way that did not make it light up. Compare the drawings and discuss questions such as:

*How do you think the light bulb needs to be connected to make it work?

*Why did this arrangement work/not work? How would you change it to make it work and why?

Review the times when the light bulb didn’t light up. Discuss questions such as:

*If the light did not turn on, what would you need to check?

12. Introduce the term ‘circuit’. What does it mean in relation to the class exploration of lighting a light bulb. Discuss other meanings of this term: fitness circuit, track used in racing etc. Add a class-generated description of ‘electric circuit’ (see note) to science chat-board.

13. Review the drawings on the board and discuss the similarities and differences in the way students have represented equipment or electric circuits. Discuss the confusion that could occur when using different ways of represent equipment, for example, some people draw different pictures to represent the same thing.

14. Explain that a way to show an electrical system is by using a circuit diagram. Standard electrical symbols are used in circuit diagrams to represent how a circuit is connected. Introduce symbols (wire, battery [cell], light bulb).

15. Model drawing a circuit on the board.

16. Students look at the different drawing of the circuits they drew on the PROBE: Lighting Up My Life sheet. Select one and represent it in their science journal as a circuit diagram using electric symbols. They are to also include a record of their ideas about the path of electrical energy as it travels around the circuit and through each of the components of the circuit.

17. Now review their cutaway diagram of how a torch could work from Lesson 1. Update this diagram to include what they now know – for example names/symbols or parts and the need for a complete circuit for the torch to light (see note).

18. Update the class science chat-board – pictures, questions, ideas, reflections using electrical symbols and add new words to the keywords section.