Circuit breakers
View Sequence overviewStudents will:
- plan and conduct a repeatable investigation including identify and control variables in a fair test.
- identify and describe materials that act as electrical insulators or conductors.
In this lesson, students will represent their understanding in these ways:
- describe how to identify an electrical conductor or insulator.
- participate in and contribute to discussions, sharing information, experiences and opinions.
In this lesson, assessment is summative.
Students working at the achievement standard (science inquiry) should have:
- identified variables to be changed, measured and controlled.
- used equipment to generate and record data with appropriate precision.
- organised, recorded and processed their data in an appropriate table.
- constructed representations that organise and process data and information and described patterns, trends and relationships.
- recognised possible sources of error and suggested improvements in the method.
Refer to the Australian Curriculum content links on the Our design decisions tab for further information.
Whole class
Class science journal (digital or hard-copy)
Demonstration copy of Testing insulators Resource sheet
Stripping pliers (to strip the insulation from the wires if required)
Materials to create a word wall
Torch
Each group
1 x 1.5V AA battery
1 x 1.5V battery holder
1 x light bulb holder
1 x 1.5V light bulb (+ spares)
6 x 10 cm length of insulated wire, with the ends stripped of insulation (+ spares)
Sticky tape
Items made from a variety of materials, to be used to test for conductivity as part of a circuit, 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
High Tech option: Multimeter to test either resistance or current through materials
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)
Testing insulators 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
Recall the experiment from the previous lesson, exploring how different circuit arrangements affected the brightness of a bulb. Discuss the factors that affected the flow of electricity around the circuit.
Invite students to recreate their circuits to provide light in the room.
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 FrameworkInterrupting the flow
Pose the question: Does tying a knot in the wire slow the movement of electrical energy?
Students try this with their circuits.
Discuss:
- how tying a knot is a variable.
- the definition of a variable.
- how testing the effect of a knot in their circuit required all other variables to be kept the same.
- how the wire allowed electricity to flow very easily, even when knotted.
- that there are some materials that do not let electricity flow through.
Ask students to disconnect and reconnect wires and observe what happens.
Discuss:
- how the electricity stopped flowing when the wires were disconnected.
- how this suggests that electricity does not flow easily through the air.
- how electricity travels more easily along wires.
Pose the question: What materials prevent the flow of electricity?
If students haven’t asked this question themselves in the TWLH chart, add it to the list of class questions and discuss that answering this question will be the centre of today’s investigation.
Alternative conceptions
What alternative conceptions about electrical energy might students hold?
Some students consider electricity moves through wires in a similar way as water moves through pipes. They consider the plastic coating around the wire ‘holds the current in’. This leads to the alternative thought that ‘squashing’ or tying a knot in the wire will slow the movement of electricity. This does not occur as the electrons can move easily along any connected metal atoms.
Some students consider electricity moves through wires in a similar way as water moves through pipes. They consider the plastic coating around the wire ‘holds the current in’. This leads to the alternative thought that ‘squashing’ or tying a knot in the wire will slow the movement of electricity. This does not occur as the electrons can move easily along any connected metal atoms.
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 FrameworkTesting materials
Brainstorm materials that could be tested to see if electricity does or does not flow through. Identify materials that could be tested for their ability to allow electricity to flow, using the materials in the equipment list or objects around the classroom as a guide.
Using Testing insulators Resource sheet, discuss and demonstrate the planning of an experiment to test which materials prevent the flow of electricity, including:
- predicting what will happen.
- the variable that will be changed.
- what will be observed.
- what will be kept the same.
- the equipment that will be needed.
- how the equipment will be set up.
Sample equipment set up:
Teams might choose to use a light bulb or an electric buzzer in their circuit to test the conductivity of materials.
HIGH TECH: Students directly test the resistance of materials or the current flowing through the material using a multimeter.
Allow time for each team to conduct their investigation and record their findings.
Variables
All scientific repeatable fair tests involve variables.
All scientific repeatable fair tests involve variables. Variables are things that need to be kept the same (controlled) except for the one thing that is deliberately changed (independent variable) so that it will cause a change in the end observation (dependent variable).
By planning for and conducting a fair test, students can make claims about material being an insulator or conductor of electrical energy.
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 conductors and insulators
Teams report back to the rest of the class on their findings, including presenting a claim that responds to the prediction(s) they made with supporting evidence and reasoning.
Encourage students to probe deeply into groups' results and claims using the science question starters.
- What did you predict would happen?
- What did you observe?
- Was your prediction different to what you observed?
- Why do you think that happened?
- What claim might you make to answer your question “What materials prevent the flow of electricity?”
- What evidence do you have to support your claim?
Introduce the terms ‘conductor’, ‘insulator’ and ‘resistance’ in reference to an electrical circuit. Suggested definitions might be:
- electrical conductors: materials that allow electrical current to pass through them.
- resistance: the measure of the difficulty of passing electrical current through a circuit.
- electrical insulators: materials that do not allow electrical current to pass through them.
Discuss:
- any patterns observed among materials that are good conductors and among those that are good insulators.
- that many metals, such as copper, iron, and steel, are good electrical conductors (low resistance). Whereas plastic, wood, glass, and rubber are good electrical insulators (high resistance).
- how electrical conductors and insulators are used in everyday ways and things.
- What happened when an electrical insulator was introduced into your circuit?
- Why do you think that the wires you use are surrounded by plastic?
- What would happen if you touched a wire in your house? Would you be an insulator or a conductor?
- As our bodies are mostly water, we are conductors.
- How are the batteries we use different from the electricity in our houses?
- The batteries are 1.5 volts. Australian houses have 240 volts in their wires.
- You might have used heat insulators in Year 3. How are heat insulators similar to electrical insulators?
Reflect on the lesson
You might:
- add relevant vocabulary to the class word wall/glossary.
- record teams' claims and evidence about circuits from their investigations in the L and H columns of the TWLH chart.
Conductors and insulators
Students have previously encountered conductivity of materials when learning about heat energy in Year 3.
In Year 3 students may have investigated heat conductors and insulators. The principles are the same: conductors allow energy to travel, and insulators resist the movement of energy. Encouraging students to make a correlation between the two forms of energy increases a student’s metacognitive processes and understanding of energy.
All materials are made of atoms. Electrons are small, negatively charged particles that form the outside part of atoms. Some materials contain electrons that held loosely by the atoms and are free to move throughout the material. Materials that have these free electrons are called electrical conductors. Metals have many free electrons and are considered to be good electrical conductors. Electrical conductors have a low resistance.
Materials such as glass or plastic have electrons that are not free to move. Therefore, they do not allow electrons to flow through them and are called electrical insulators. Common electrical insulators include plastics, rubber, wood and glass. A plastic electrical insulator is used on electric switches and wires to prevent shock or electrical injury to a person using them. Electrical insulators have a high resistance.
In Year 3 students may have investigated heat conductors and insulators. The principles are the same: conductors allow energy to travel, and insulators resist the movement of energy. Encouraging students to make a correlation between the two forms of energy increases a student’s metacognitive processes and understanding of energy.
All materials are made of atoms. Electrons are small, negatively charged particles that form the outside part of atoms. Some materials contain electrons that held loosely by the atoms and are free to move throughout the material. Materials that have these free electrons are called electrical conductors. Metals have many free electrons and are considered to be good electrical conductors. Electrical conductors have a low resistance.
Materials such as glass or plastic have electrons that are not free to move. Therefore, they do not allow electrons to flow through them and are called electrical insulators. Common electrical insulators include plastics, rubber, wood and glass. A plastic electrical insulator is used on electric switches and wires to prevent shock or electrical injury to a person using them. Electrical insulators have a high resistance.