Conductors and Insulators

Overview

In this fourth lesson of Circuits, Current, and Creativity, students investigate which classroom materials allow charge to move through a complete circuit. They use evidence from a low-voltage circuit test to classify conductors and insulators, then revise circuit diagrams and explain how material choice affects the path of charge.

Learning intentions

Students will be able to:

• Test materials safely in a simple electric circuit.
• Record observations and classify materials as conductors or insulators.
• Use evidence to explain why metal wire permits charge movement while plastic or paper interrupts the path.
• Revise a circuit diagram and communicate findings clearly in writing.

Success criteria

• I can predict and test whether a material conducts electricity.
• I can identify evidence that a circuit is complete or interrupted.
• I can correctly label conductors and insulators.
• I can revise a circuit diagram and explain my reasoning using scientific vocabulary.

Curriculum links

• Science and Engineering Practices: planning and carrying out investigations, analyzing data, and communicating information.
• Common Core literacy in science: follow a multistep procedure, record observations, and describe cause-and-effect relationships using evidence.
• Washington State STEM learning: develop and use models to represent how components interact in a system.
• Mathematics connections: interpret positive and negative changes in a system and describe how quantities combine to produce an observable result.

Lesson structure (40 minutes)

1. 0–5 min · Hook and prior knowledge. Teacher displays a simple circuit containing a battery, lamp, and gap, then asks, “Would the lamp light if we filled the gap with a plastic straw? What about a metal paper clip?” Open with the hook and prediction slides and elicit predictions without confirming answers. Students make an individual prediction, then share their reasoning with a partner.

2. 5–10 min · Direct teach and safety. Teacher uses the conductors, insulators, and safety slides to review that a conductor allows charge to move through a complete path, while an insulator resists movement and can interrupt the path. Demonstrate a low-voltage circuit and model testing one material at a time. Emphasize: use only the provided batteries, never household outlets, do not short-circuit the battery, disconnect the circuit when finished, and report warm or damaged equipment. Students identify the independent variable (material), dependent variable (lamp or buzzer response), and one controlled variable.

3. 10–23 min · Team investigation. Teacher places students in groups of four with assigned roles: builder, tester, recorder, and safety manager. Distribute the conductors and insulators investigation sheet and provide each group with a battery pack, lamp or buzzer, connecting wires, and assorted safe materials such as metal, plastic, paper, wood, and rubber. Students predict, insert one material into the circuit gap, observe whether the lamp lights or buzzer sounds, and record three trials or repeated checks. Groups classify each item and note surprising results.

4. 23–29 min · Evidence discussion. Teacher pauses testing and asks groups to compare results using the results discussion slides. Prompt: “What observation is evidence that charge completed the path?” and “Why should we test more than once?” Students compare classifications with another group, resolve disagreements by rechecking materials, and write one evidence-based claim on the worksheet.

5. 29–36 min · Revise circuit models. Teacher displays the diagram revision slides and models revising a circuit diagram to show a metal connector completing the path and a plastic or paper connector interrupting it. Students revise two diagrams on the worksheet: one working circuit using metal wire and one nonworking circuit using an insulator. They add arrows or labels showing the continuous path of charge and write a two-sentence explanation using “because” and evidence from their test.

6. 36–40 min · Plenary and exit check. Teacher returns to the opening predictions with the conclusion and exit prompt slide. Students complete the final worksheet prompt: “A metal paper clip conducts, but a plastic strip does not. Use the words complete path, charge, and insulator to explain why.” Invite two students to share, then collect worksheets to identify misconceptions for the next lesson.

Resources

• the Conductors and Insulators slide deck
• the conductors and insulators investigation sheet
• Low-voltage battery packs
• Small lamps or buzzers
• Insulated connecting wires with exposed ends or alligator clips
• Safe classroom test materials: paper, plastic, rubber, wood, and metal
• Safety glasses
• Pencils and colored pencils
• Student role cards or board display

Assessment

• Listen to predictions and questioning during the hook; check whether students distinguish a complete path from simply having a battery.
• Review investigation tables for repeated observations, sensible classifications, and evidence-based claims.
• Use the final written explanation to assess whether students can connect material properties to charge movement and revise a model accurately.

Differentiation

• Provide a completed example circuit, a word bank (conductor, insulator, charge, complete path, interrupt), and sentence frames such as “The lamp ____ because ____.”
• Pair students strategically and assign specific roles; allow students who need support to draw arrows and label diagrams before writing their explanation.
• For EAL students, show real materials while introducing each term, repeat directions in short steps, and permit oral rehearsal with a partner before writing.
• Challenge ready students to explain why an insulated wire can still conduct through its metal core, or to predict whether a material might conduct only under particular conditions. Ensure students with sensory or motor needs can take roles such as recorder, observer, or diagram designer.