Physics · Year 12

Active learning ideas

Impulse and Force

Active learning works for Impulse and Force because students often struggle with visualising invisible fields and forces. Hands-on experiments let them observe magnetic forces directly and feel the effects of changing variables like current or angle.

• ACARA Content Descriptions
• AC9SPU01

• 20–60 min
• Pairs → Whole Class
• 3 activities

Activity 01

• Inquiry Circle
• 60 min · Small Groups

Inquiry Circle: Build a DC Motor

Students work in small groups to construct a simple electric motor using a battery, a magnet, and a coil of wire. They must troubleshoot their design and explain how the Right-Hand Rule applies to the motion they observe.

Explain how crumple zones in cars reduce injury during a collision.

Facilitation Tip

During the DC Motor Build, circulate and ask groups to explain how the commutator reverses current to maintain rotation, rather than just watching it spin.

What to look for

Present students with a scenario: A 2 kg ball moving at 10 m/s collides with a wall and rebounds at 8 m/s. Ask them to calculate the impulse delivered to the ball and the change in its momentum. Provide the formula for momentum (p=mv).

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

Activity 02

• Stations Rotation
• 50 min · Small Groups

Stations Rotation: Magnetic Force Applications

Stations include a mass spectrometer simulation, a loudspeaker teardown, and a 'jumping wire' demonstration. Students rotate to identify how the magnetic force is being used in each specific technology.

Evaluate the impact of varying contact time on the force experienced during an impact.

What to look for

Pose the question: 'Why does a stunt performer prefer to fall onto a pile of soft cushions rather than a hard concrete floor?' Guide students to explain their answer using the concepts of impulse, force, and time of contact.

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

Activity 03

• Think-Pair-Share
• 20 min · Pairs

Think-Pair-Share: Particle Paths

Students are given diagrams of charged particles entering magnetic fields at different angles. They must predict the resulting path (circular, helical, or straight) and explain their reasoning to a partner before a class-wide check.

Design a safety device that utilizes the principle of impulse to minimize force.

What to look for

Ask students to write down one real-world example of impulse being used to reduce force, other than car crumple zones. They should briefly explain how the time of contact is modified in their example.

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

A few notes on teaching this unit

Teach this topic by combining physical models with peer explanations. Avoid over-relying on abstract diagrams alone, since the three-dimensional nature of magnetic fields is hard to grasp from 2D images. Research shows that using the Right-Hand Rule kinesthetically, with students miming directions while holding a wire model, improves spatial understanding.

Successful learning looks like students confidently predicting directions of force, explaining why motors spin, and connecting particle paths to real-world devices. They should articulate the perpendicular relationship between force, velocity, and field.

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Watch Out for These Misconceptions

• During the Jumping Wire experiment in Station Rotation, watch for students attributing the wire's movement to the metal being magnetic.

  Redirect by asking, 'What happens if we replace the copper wire with an aluminum wire of the same gauge? The wire still moves, proving it is the current that matters, not the metal's magnetic properties.'

• During the Think-Pair-Share activity on Particle Paths, watch for students drawing force vectors parallel to magnetic field lines.

  Have students use their hands to model the wire's position and direction of current while tracing the field lines with the other hand, reinforcing the perpendicular relationship.

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Methods used in this brief

• Inquiry Circle
• Stations Rotation
• Think-Pair-Share