Science · Class 10

Active learning ideas

Ohm's Law and Resistance

Active learning helps students grasp Ohm's Law because it turns abstract equations into visible, measurable outcomes. Working with real circuits and resistors makes voltage, current, and resistance tangible, building confidence in applying classroom concepts outdoors.

• CBSE Learning Outcomes
• CBSE: Electricity - Class 10

• 30–45 min
• Pairs → Whole Class
• 4 activities

Activity 01

• Inquiry Circle
• 40 min · Pairs

Pairs Lab: Verifying Ohm's Law

Each pair assembles a circuit with a 6V battery, rheostat, ammeter, and voltmeter across a fixed resistor. They vary voltage from 1V to 5V, record current readings, plot V-I graph, and find slope as R. Discuss if line passes through origin.

Explain Ohm's Law and its relationship between voltage, current, and resistance.

Facilitation Tip

During Pairs Lab: Verifying Ohm's Law, remind pairs to record both ammeter and voltmeter readings immediately after each adjustment to avoid confusion between trials.

What to look for

Present students with a problem: 'A copper wire is 10 meters long and has a cross-sectional area of 2 mm². If the resistivity of copper is 1.72 x 10⁻⁸ Ωm, calculate its resistance.' Ask students to show their steps and final answer on a mini-whiteboard.

• Analyze
• Evaluate
• Create
• Self-Management
• Self-Awareness

Activity 02

• Inquiry Circle
• 35 min · Small Groups

Small Groups: Length and Resistance

Groups use constantan wire cut to 20cm, 40cm, 60cm lengths with same thickness. Connect each to a circuit, measure voltage and current at fixed setting, calculate R. Predict pattern for 80cm and test.

Analyze the factors that influence the resistance of a conductor.

Facilitation Tip

In Small Groups: Length and Resistance, encourage students to measure wire lengths in metres and cross-check with a ruler to minimise measurement errors.

What to look for

On a small slip of paper, ask students to: 1. State Ohm's Law in their own words. 2. List two factors that affect the resistance of a wire. 3. Write one question they still have about resistance.

• Analyze
• Evaluate
• Create
• Self-Management
• Self-Awareness

Activity 03

• Stations Rotation
• 45 min · Small Groups

Stations Rotation: Material Resistivity

Set three stations with copper, nichrome, and pencil lead samples of same dimensions. Students measure R at each using multimeter, compare values, and link to electron mobility. Rotate every 10 minutes.

Predict how changes in material, length, or area affect resistance.

Facilitation Tip

At Station Rotation: Material Resistivity, have students test wires in the same order to control temperature effects between samples.

What to look for

Pose the question: 'Imagine you have two wires of the same material and length, but one is twice as thick as the other. How will their resistances compare?' Facilitate a class discussion, guiding students to explain their reasoning using the concept of cross-sectional area.

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

Activity 04

• Inquiry Circle
• 30 min · Individual

Individual Inquiry: Area Effect

Students twist two thin wires together to halve effective length or use thicker wire. Measure R before and after, calculate percentage change, and explain using formula. Share findings in class plenary.

Explain Ohm's Law and its relationship between voltage, current, and resistance.

Facilitation Tip

For Individual Inquiry: Area Effect, provide graph paper so students can plot area versus resistance directly and see the inverse pattern.

What to look for

Present students with a problem: 'A copper wire is 10 meters long and has a cross-sectional area of 2 mm². If the resistivity of copper is 1.72 x 10⁻⁸ Ωm, calculate its resistance.' Ask students to show their steps and final answer on a mini-whiteboard.

• Analyze
• Evaluate
• Create
• Self-Management
• Self-Awareness

A few notes on teaching this unit

Teachers should begin with hands-on labs before theory to prevent students from memorising V = I R without understanding. Use real instruments, not simulations, to build familiarity with measuring devices. Avoid rushing through calculations; instead, let students struggle slightly with units and conversions, as this deepens retention. Research shows that students who manually graph data remember relationships longer than those who only see pre-made graphs.

By the end of these activities, students will confidently set up simple circuits, measure voltage and current accurately, and explain how resistance changes with wire properties. They will also justify their findings using graphs and calculations, not just memory.

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Watch Out for These Misconceptions

• During Small Groups: Length and Resistance, watch for students claiming that longer wires have less resistance.

  During Small Groups: Length and Resistance, have students plot length on the x-axis and resistance on the y-axis; the upward slope will quickly correct this idea with concrete evidence.

• During Individual Inquiry: Area Effect, watch for students believing thicker wires have higher resistance.

  During Individual Inquiry: Area Effect, ask students to calculate resistance for two wires with areas 1 mm² and 2 mm²; the halving of resistance will make the inverse relationship clear through their own calculations.

• During Pairs Lab: Verifying Ohm's Law, watch for students assuming Ohm's Law applies at any temperature.

  During Pairs Lab: Verifying Ohm's Law, instruct students to keep the circuit off between readings to maintain a steady temperature, and prompt them to discuss why linearity might break if wires heat up.

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Methods used in this brief

• Inquiry Circle
• Stations Rotation