Circuit breakers
View Sequence overviewStudents will:
- use their knowledge of conductors and insulators to make an electrical switch.
Students will represent their understanding as they:
- design and make an electrical switch.
- draw a labelled diagram of an electrical switch.
- participate in and contribute to discussions, sharing information, experiences and opinions.
In this lesson, assessment is formative.
Feedback might focus on
- Are students able to collaborate to design criteria to evaluate the effectiveness of their switch design?
- Are students able to test a range of materials and equipment to determine their effectiveness in meeting the criteria?
- Are students able to generate, iterate, and communicate their design ideas and decisions?
- Are students able to use evidence and reasoning to justify the decisions they made in their designs?
Whole class
Class science journal (digital or hard-copy)
Stripping pliers (to strip the insulation from the wires if required)
Demonstration copy of Switch planner Resource sheet
Materials to create a word wall
Each group
Small torch
2 x 1.5V AA battery
2 x 1.5V battery holder
4 x light bulb holder
4 x 1.5V light bulb (+ spares)
10 x 10 cm length of insulated wire, with the ends stripped of insulation (+ spares)
Sticky tape
Items made from a variety of materials, used in Lesson 5 to test for conductivity, including:
- wooden items (e.g. toothpicks, corks)
- plastic items (e.g. straws)
- rubber items (e.g. rubber bands, balloons)
- metal items (e.g. paperclips, thumb tacks, aluminium foil, split pins)
Optional: electric buzzer
NOTE: If no electrical equipment is available, the Circuit Construction Kit on the PHET website can be used.
Each student
Individual science journal (digital or hard-copy)
Switch planner Resource sheet
Lesson
The Inquire phase allows students to cycle progressively and with increasing complexity through the key science ideas related to the core concepts. Each Inquire cycle is divided into three teaching and learning routines that allow students to systematically build their knowledge and skills in science and incorporate this into their current understanding of the world.
When designing a teaching sequence, it is important to consider the knowledge and skills that students will need in the final Act phase. Consider what the students already know and identify the steps that need to be taken to reach the level required. How could you facilitate students’ understanding at each step? What investigations could be designed to build the skills at each step?
Read more about using the LIA FrameworkRe-orient
Present students with the collection of items used to test conductivity in the previous lesson, and ask them to sort the materials into insulators and conductors.
Remind students of the torch examined in the Launch phase and its switch. Discuss what it would be like trying to switch on a torch in the dark during a blackout.
The Inquire phase allows students to cycle progressively and with increasing complexity through the key science ideas related to the core concepts. Each Inquire cycle is divided into three teaching and learning routines that allow students to systematically build their knowledge and skills in science and incorporate this into their current understanding of the world.
When designing a teaching sequence, it is important to consider the knowledge and skills that students will need in the final Act phase. Consider what the students already know and identify the steps that need to be taken to reach the level required. How could you facilitate students’ understanding at each step? What investigations could be designed to build the skills at each step?
Read more about using the LIA FrameworkIdentifying and constructing questions is the creative driver of the inquiry process. It allows students to explore what they know and how they know it. During the Inquire phase of the LIA Framework, the Question routine allows for past activities to be reviewed and to set the scene for the investigation that students will undertake. The use of effective questioning techniques can influence students’ view and interpretation of upcoming content, open them to exploration and link to their current interests and science capital.
When designing a teaching sequence, it is important to spend some time considering the mindset of students at the start of each Inquire phase. What do you want students to be thinking about, what do they already know and what is the best way for them to approach the task? What might tap into their curiosity?
Read more about using the LIA FrameworkQuestioning switches
Pose the question: What makes a good switch?
Discuss factors which will become success criteria for the successful design of a switch. For example:
- turn the light off and on
- easy to use
- not electrocute someone
- quick to change/switch
- people of all abilities able to use it (discuss what this means)
Modelling design processes
When starting on the design process, it is important to develop a set of criteria.
When starting on the design process, it is important to develop a set of criteria to judge the various iterations of the prototype. These criteria should be SMART goals (specific, measurable, achievable, relevant and time-based) that are directly relevant to the person who will use the final product. Students can do this by imagining a person they know, and thinking of how that person will use the product.
When starting on the design process, it is important to develop a set of criteria to judge the various iterations of the prototype. These criteria should be SMART goals (specific, measurable, achievable, relevant and time-based) that are directly relevant to the person who will use the final product. Students can do this by imagining a person they know, and thinking of how that person will use the product.
The Inquire phase allows students to cycle progressively and with increasing complexity through the key science ideas related to the core concepts. Each Inquire cycle is divided into three teaching and learning routines that allow students to systematically build their knowledge and skills in science and incorporate this into their current understanding of the world.
When designing a teaching sequence, it is important to consider the knowledge and skills that students will need in the final Act phase. Consider what the students already know and identify the steps that need to be taken to reach the level required. How could you facilitate students’ understanding at each step? What investigations could be designed to build the skills at each step?
Read more about using the LIA FrameworkThe Investigate routine provides students with an opportunity to explore the key ideas of science, to plan and conduct an investigation, and to gather and record data. The investigations are designed to systematically develop content knowledge and skills through increasingly complex processes of structured inquiry, guided inquiry and open inquiry approaches. Students are encouraged to process data to identify trends and patterns and link them to the real-world context of the teaching sequence.
When designing a teaching sequence, consider the diagnostic assessment (Launch phase) that identified the alternative conceptions that students held. Are there activities that challenge these ideas and provide openings for discussion? What content knowledge and skills do students need to be able to complete the final (Act phase) task? How could you systematically build these through the investigation routines? Are there opportunities to build students’ understanding and skills in the science inquiry processes through the successive investigations?
Read more about using the LIA FrameworkDesigning switches
Introduce the electric symbols for open and closed switches:
Ask students which position represents a switch that allows electricity to flow and why they think that. Discuss if the moving part of a switch should be made out of a conductor or insulator.
Students can redraw the circuit they used to test conductors and insulators in the previous lesson, now using the symbols for a switch. They should annotate the diagram to describe the role of the switch in a circuit.
Ask: What would be an effective design for a switch?
Students draw different versions of a switch in the Switch planner Resource sheet. Their switch should use their selected materials from the previous lesson, and should follow the criteria decided in the Question routine.
Example of a criteria table:
Student teams should build and test their designer switch using a simple circuit from the previous lesson.
Allow students time to complete their investigation.
Switches
A switch is a device in an electric circuit that can provide a path for electrons to flow depending on whether it is ‘closed’ or ‘open’.
A switch is a device in an electric circuit that can either provide a path for electrons to flow through or not, depending on whether it is ‘closed’ or ‘open’.
To make a paperclip switch, wrap the ends of wire around split pins. Place a plain wire paperclip around the base of one split pin before anchoring it. When the paperclip touches the second pin the circuit will complete.
To make a pressure switch, cover two cards with aluminium foil. Tape the ends of a wire to each one. Place unwrapped cardboard between the two as a spacer (the cardboard is an insulator. When you press down the aluminium sheets will touch completing the circuit.
A switch is a device in an electric circuit that can either provide a path for electrons to flow through or not, depending on whether it is ‘closed’ or ‘open’.
To make a paperclip switch, wrap the ends of wire around split pins. Place a plain wire paperclip around the base of one split pin before anchoring it. When the paperclip touches the second pin the circuit will complete.
To make a pressure switch, cover two cards with aluminium foil. Tape the ends of a wire to each one. Place unwrapped cardboard between the two as a spacer (the cardboard is an insulator. When you press down the aluminium sheets will touch completing the circuit.
The Inquire phase allows students to cycle progressively and with increasing complexity through the key science ideas related to the core concepts. Each Inquire cycle is divided into three teaching and learning routines that allow students to systematically build their knowledge and skills in science and incorporate this into their current understanding of the world.
When designing a teaching sequence, it is important to consider the knowledge and skills that students will need in the final Act phase. Consider what the students already know and identify the steps that need to be taken to reach the level required. How could you facilitate students’ understanding at each step? What investigations could be designed to build the skills at each step?
Read more about using the LIA FrameworkFollowing an investigation, the Integrate routine provides time and space for data to be evaluated and insights to be synthesized. It reveals new insights, consolidates and refines representations, generalises context and broadens students’ perspectives. It allows student thinking to become visible and opens formative feedback opportunities. It may also lead to further questions being asked, allowing the Inquire phase to start again.
When designing a teaching sequence, consider the diagnostic assessment that was undertaken during the Launch phase. Consider if alternative conceptions could be used as a jumping off point to discussions. How could students represent their learning in a way that would support formative feedback opportunities? Could small summative assessment occur at different stages in the teaching sequence?
Read more about using the LIA FrameworkIdentifying success
Discuss successful designs from each student team, comparing them to the identified class criteria.
- Which material did you use to make your switch? Why did you choose that material?
- What other material could you have also used? How do you know that?
- How does your switch match the criteria we identified?
- What part does the switch play in the circuit?
- When it is not connected, it stops the flow of the electrical energy. When it is connected, the electrical energy can flow.
- Why do we use a switch in a circuit?
- To have more control over when the electrical energy is flowing; so that energy is not wasted; so that the battery does not go flat.
- How many switches are there in the classroom? In your house? Is there one switch for everything?
- Can some switches be turned on in a room, while other switches in the same room are turned off?
Adapting to your context
Depending on the equipment available in the class, students' switches can be tested for different purposes.
Depending on the equipment available in the class, students' switches can be tested for different purposes.
If the class has enough buzzers students could create switches to send Morse code messages. These switches would need to be turned on and off quickly enough to make the message ‘readable’.
Students might use their switches to control different types of electrical circuits. This is an opportunity to challenge some students. They could make a switch and circuit that (in increasing difficulty):
- turns all lights on/off.
- turns half the lights on/off.
- model a fridge where the light goes on when the door is open.
Depending on the equipment available in the class, students' switches can be tested for different purposes.
If the class has enough buzzers students could create switches to send Morse code messages. These switches would need to be turned on and off quickly enough to make the message ‘readable’.
Students might use their switches to control different types of electrical circuits. This is an opportunity to challenge some students. They could make a switch and circuit that (in increasing difficulty):
- turns all lights on/off.
- turns half the lights on/off.
- model a fridge where the light goes on when the door is open.
The Inquire phase allows students to cycle progressively and with increasing complexity through the key science ideas related to the core concepts. Each Inquire cycle is divided into three teaching and learning routines that allow students to systematically build their knowledge and skills in science and incorporate this into their current understanding of the world.
When designing a teaching sequence, it is important to consider the knowledge and skills that students will need in the final Act phase. Consider what the students already know and identify the steps that need to be taken to reach the level required. How could you facilitate students’ understanding at each step? What investigations could be designed to build the skills at each step?
Read more about using the LIA FrameworkThe Investigate routine provides students with an opportunity to explore the key ideas of science, to plan and conduct an investigation, and to gather and record data. The investigations are designed to systematically develop content knowledge and skills through increasingly complex processes of structured inquiry, guided inquiry and open inquiry approaches. Students are encouraged to process data to identify trends and patterns and link them to the real-world context of the teaching sequence.
When designing a teaching sequence, consider the diagnostic assessment (Launch phase) that identified the alternative conceptions that students held. Are there activities that challenge these ideas and provide openings for discussion? What content knowledge and skills do students need to be able to complete the final (Act phase) task? How could you systematically build these through the investigation routines? Are there opportunities to build students’ understanding and skills in the science inquiry processes through the successive investigations?
Read more about using the LIA FrameworkElectrifying rooms
Challenge the student teams to replicate how the electricity might work in their houses. Are they able to have different switches control different lights?
Ask teams to draw a line down the centre of a page to represent two rooms in their house, then place 1-2 bulbs and 1 student switch in each ‘room’. The team should connect the bulbs and switches so that each switch activates the lights in its room only, i.e. the switch in room 1 activates the lights in room 1 and the switch in room 2 activate the lights in room 2. The circuit can only use a single battery.
Example circuits include:
Switch 1 controlling light A+B; Switch 2 controlling light C+D
Switch 1 controls lights A+B+C+D, and Switch 2 controls lights C+D. For lights C+D, both switches 1 and 2 need to be closed.
If students have difficulty, suggest that they follow the flow of electricity with their finger from the battery, along the linked wires and closed switches. This provides an opportunity to reinforce that a circuit requires a ‘closed loop’.
The Inquire phase allows students to cycle progressively and with increasing complexity through the key science ideas related to the core concepts. Each Inquire cycle is divided into three teaching and learning routines that allow students to systematically build their knowledge and skills in science and incorporate this into their current understanding of the world.
When designing a teaching sequence, it is important to consider the knowledge and skills that students will need in the final Act phase. Consider what the students already know and identify the steps that need to be taken to reach the level required. How could you facilitate students’ understanding at each step? What investigations could be designed to build the skills at each step?
Read more about using the LIA FrameworkFollowing an investigation, the Integrate routine provides time and space for data to be evaluated and insights to be synthesized. It reveals new insights, consolidates and refines representations, generalises context and broadens students’ perspectives. It allows student thinking to become visible and opens formative feedback opportunities. It may also lead to further questions being asked, allowing the Inquire phase to start again.
When designing a teaching sequence, consider the diagnostic assessment that was undertaken during the Launch phase. Consider if alternative conceptions could be used as a jumping off point to discussions. How could students represent their learning in a way that would support formative feedback opportunities? Could small summative assessment occur at different stages in the teaching sequence?
Read more about using the LIA FrameworkJustifying design decisions
After students have completed their investigations, use the QCER communication tool to discuss each team's successful designs and correlate them to the functions in a house.
- Did your design meet the criteria?
- What evidence do you have to support your claim?
- How does your design meet the criteria)?
- What could you have connected instead of lights?
- Why would it be important to use a switch for more than one thing?
Reflect on the lesson
You might:
- discuss examples of where the concepts of this lesson might apply in daily life.
- Have you ever had the electricity go off in one part of your house?
- Why do you think this might happen?
- Is this the same as a blackout?
- Could big electrical circuits connect the houses on one block separately from the block across the street?
- Could this be the reason why one street of a suburb has a blackout and not the next suburb?
- Has this ever happened to you?
- record teams' claims and evidence about circuits from their investigations in the L and H columns of the TWLH chart.