Physics · Year 11

Active learning ideas

Electric Current and Resistance

Electric current and resistance are abstract concepts that become concrete when students build and test circuits themselves. Active learning helps students move from memorizing formulas to recognizing how changes in voltage, resistance, and wire properties directly affect current flow in real time.

• ACARA Content Descriptions
• AC9SPU14

• 30–50 min
• Pairs → Whole Class
• 4 activities

Activity 01

• Case Study Analysis
• 45 min · Pairs

Circuit Building: Series Circuits

Provide batteries, resistors, wires, and ammeters. Students connect components in series, measure current and voltage across each resistor, then record data in tables. Discuss why current remains constant while voltage divides.

Explain the conditions necessary for a continuous electric current to flow.

Facilitation Tip

During Circuit Building: Series Circuits, circulate with a multimeter to ensure students connect ammeters in series correctly before powering circuits.

What to look for

Provide students with a simple circuit diagram containing a battery and a resistor. Ask them to calculate the current flowing through the circuit if the voltage is 12V and the resistance is 4Ω. Then, ask them to state one condition necessary for this current to flow.

• Analyze
• Evaluate
• Create
• Decision-Making
• Self-Management

Activity 02

• Progettazione (Reggio Investigation)
• 50 min · Small Groups

Progettazione (Reggio Investigation): Wire Resistance Factors

Supply wires of varying lengths, diameters, and materials. Students build simple circuits, measure resistance with multimeters, and plot graphs of resistance against length or area. Calculate resistivity from data.

Differentiate between ohmic and non-ohmic conductors.

Facilitation Tip

During Investigation: Wire Resistance Factors, provide wire samples of the same material but different thicknesses so students isolate one variable at a time.

What to look for

Present students with a graph showing current versus voltage for two different conductors. Ask them to identify which conductor is ohmic and which is non-ohmic, and to justify their answer by referring to the shape of the graph and Ohm's Law.

• Understand
• Apply
• Analyze
• Self-Awareness
• Social Awareness
• Relationship Skills

Activity 03

• Case Study Analysis
• 40 min · Pairs

Comparison: Ohmic vs Non-Ohmic

Set up circuits with resistors and filament lamps. Students vary voltage, plot V-I graphs using data loggers, and identify linear vs nonlinear trends. Label graphs and explain differences.

Analyze how the physical properties of a wire affect its resistance.

Facilitation Tip

During Comparison: Ohmic vs Non-Ohmic, use identical lamps and resistors so students focus on graph shape rather than component differences.

What to look for

Pose the question: 'Imagine you need to reduce the resistance in a circuit. What are three specific changes you could make to the wire or components?' Facilitate a class discussion where students share their ideas and explain the underlying physics.

• Analyze
• Evaluate
• Create
• Decision-Making
• Self-Management

Activity 04

• Case Study Analysis
• 30 min · Whole Class

Whole Class: Resistance Demo Relay

Demonstrate circuits on projector; pairs predict outcomes for changes like adding resistors, then test predictions on mini-circuits. Share results in class discussion.

Explain the conditions necessary for a continuous electric current to flow.

Facilitation Tip

During Resistance Demo Relay, prepare three stations with different resistors and have groups rotate every 4 minutes to collect data and share observations.

What to look for

Provide students with a simple circuit diagram containing a battery and a resistor. Ask them to calculate the current flowing through the circuit if the voltage is 12V and the resistance is 4Ω. Then, ask them to state one condition necessary for this current to flow.

• Analyze
• Evaluate
• Create
• Decision-Making
• Self-Management

A few notes on teaching this unit

Teach Ohm’s law conceptually before symbolically. Use analogies like water flow in pipes to explain resistance and voltage, but transition quickly to hands-on measurement to avoid over-reliance on metaphors. Avoid presenting Ohm’s law as a universal rule early on, as students may misapply it later. Instead, let them discover exceptions during the ohmic vs non-ohmic activity.

Students should confidently predict, measure, and explain how electric current behaves in series circuits and how resistance changes with wire properties. They should differentiate ohmic from non-ohmic conductors using data and graphs, and articulate the role of potential difference in maintaining current.

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Watch Out for These Misconceptions

• During Circuit Building: Series Circuits, watch for students who believe resistors consume current.

  Have students measure current at multiple points in the circuit using ammeters. They will observe constant current and see that voltage drops across resistors instead, reinforcing the idea that charge is not used up but transformed.

• During Investigation: Wire Resistance Factors, watch for students who think thicker wires increase resistance.

  Have students plot resistance versus wire thickness on graph paper. They will see a clear inverse relationship, which they can explain using the formula R = ρL/A and the idea of more charge carriers in thicker wires.

• During Comparison: Ohmic vs Non-Ohmic, watch for students who assume all conductors obey Ohm’s law.

  During graphing, ask students to compare straight-line versus curved I-V graphs. They will identify that temperature changes in the lamp cause non-ohmic behavior, linking the graph shape to real-world conditions.

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Methods used in this brief

• Case Study Analysis
• Progettazione (Reggio Investigation)