Physics · Grade 12

Active learning ideas

Impulse and Momentum

Active learning helps students grasp impulse and momentum because these concepts rely on visualizing forces acting over time, which is easier when students manipulate materials and observe real-time data. When students experience collisions firsthand, they connect abstract equations to tangible outcomes, making the physics more memorable and meaningful.

• Ontario Curriculum Expectations
• HS.PS2.A.1
• HS.PS2.B.1

• 40–60 min
• Small Groups
• 3 activities

Activity 01

• Inquiry Circle
• 60 min · Small Groups

Inquiry Circle: The Egg Drop Reimagined

Instead of just building a cage, students must use sensors to measure the force and time of impact. They use the impulse-momentum theorem to explain exactly how their design reduced the peak force to keep the egg intact.

Explain how the impulse-momentum theorem explains the effectiveness of automotive crumple zones.

Facilitation Tip

In The Egg Drop Reimagined, circulate to ensure groups test at least three different padding materials and record the force data from the sensors before discussing results.

What to look for

Provide students with a scenario: A 1000 kg car traveling at 20 m/s collides with a stationary wall and comes to rest in 0.2 seconds. Ask them to calculate the impulse experienced by the car and the average force exerted by the wall on the car.

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

Activity 02

• Stations Rotation
• 50 min · Small Groups

Stations Rotation: Collision Lab

Students move between stations with air tracks or low-friction carts. They predict and then measure outcomes for elastic collisions, completely inelastic collisions (sticking), and explosions (pushing apart), verifying conservation laws at each stop.

Analyze the change in momentum for objects experiencing varying forces over time.

Facilitation Tip

In the Collision Lab stations, assign roles so every student handles equipment, collects data, and contributes to the analysis to prevent passive participation.

What to look for

Present students with two collision scenarios: one elastic and one inelastic. Ask them to write down whether momentum is conserved in each case and whether kinetic energy is conserved in each case, justifying their answers.

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

Activity 03

• Peer Teaching
• 40 min · Small Groups

Peer Teaching: Sports Physics

Each group chooses a sport (e.g., lacrosse, curling, or soccer) and creates a 3-minute 'coach's talk' explaining how momentum and impulse are used to maximize performance or safety in that specific context.

Predict the final velocity of an object after an impulse is applied.

Facilitation Tip

For Peer Teaching: Sports Physics, encourage students to select a sport they know well to make the physics connections more authentic and engaging.

What to look for

Pose the question: 'How does the impulse-momentum theorem explain why it is safer to fall on a soft surface like a mattress than a hard surface like concrete?' Guide students to discuss the role of impact time in reducing force.

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

A few notes on teaching this unit

Teach this topic by starting with qualitative experiences before introducing equations, as research shows students grasp abstract concepts better when they first observe phenomena. Avoid rushing to calculations; instead, use slow-motion videos and real-time data collection to build intuition. Emphasize the role of time in impulse, as this is the key insight students often miss when relying solely on formulas.

Students should be able to explain how the duration of a collision affects the force experienced by an object, apply the impulse-momentum theorem to solve problems, and analyze collisions in one and two dimensions. Successful learning includes accurate calculations, thoughtful justifications for conservation laws, and clear communication of their reasoning in group discussions.

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Watch Out for These Misconceptions

• During Peer Teaching: Sports Physics, watch for students who conflate momentum with kinetic energy when explaining collisions.

  Have students sort collision scenarios into categories (elastic, inelastic, perfectly inelastic) and justify their choices using both momentum and kinetic energy tables provided during the activity.

• During the Collision Lab, watch for students who believe the truck exerts more force than the car in a collision.

  Use the force probe data to have students compare the force-time graphs for each object, and discuss how Newton's Third Law applies to the identical force spikes in real-time.

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Methods used in this brief

• Inquiry Circle
• Stations Rotation
• Peer Teaching