Physics · 5th Year

Active learning ideas

Making Impacts Safer

Active learning works for this topic because force and momentum are abstract ideas that become concrete when students physically manipulate materials and observe collisions. When students drop eggs or test toy cars, they directly witness how padding changes outcomes, making the impulse-momentum theorem tangible rather than theoretical.

• NCCA Curriculum Specifications
• NCCA: Primary Curriculum - Science - Energy and Forces

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

Activity 01

• Problem-Based Learning
• 50 min · Small Groups

Egg Drop Lab: Padding Designs

Provide eggs, tape, and materials like bubble wrap, foam, and newspaper. Students in groups design and build protective padding, drop eggs from 2 meters, and video impacts to measure contact time. Discuss which designs best extend time and prevent breakage.

Why do playgrounds have soft surfaces?

Facilitation Tip

During the Egg Drop Lab, circulate with a force sensor and ask groups to watch how the padding material changes the force peak on their graphs as they vary thickness and type.

What to look for

Present students with two scenarios: a cyclist falling onto asphalt and a cyclist falling onto grass. Ask them to write one sentence explaining which scenario would likely result in less force on the cyclist and why, referencing contact time.

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

Activity 02

• Problem-Based Learning
• 35 min · Pairs

Video Analysis: Hard vs Soft Landings

Drop steel balls from 1 meter onto concrete and mats. Pairs use phone slow-motion video to count frames during impact and calculate average force with F = mΔv/Δt. Compare results and graph force reductions.

How do helmets protect your head?

Facilitation Tip

For the Video Analysis, play the high-speed clips frame by frame to let students count how many frames the object takes to stop on each surface.

What to look for

Pose the question: 'If a helmet is designed to protect your head, how does it achieve this protection?' Facilitate a discussion where students explain the role of padding in increasing impact time and decreasing force, using the impulse-momentum theorem.

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

Activity 03

• Problem-Based Learning
• 45 min · Small Groups

Toy Car Crash Test: Crumple Zones

Roll toy cars down ramps into barriers with varying padding. Groups measure stopping distances and times, estimate forces, and redesign barriers for safer stops. Share data class-wide.

What happens if you jump onto a hard floor versus a soft mat?

Facilitation Tip

In the Toy Car Crash Test, ensure students measure crumple zone deformation and compare it to undamaged cars to connect material choice to energy absorption.

What to look for

Give students a scenario: An object with a momentum change of 10 kg m/s hits a surface. If it hits a hard surface for 0.01 seconds, what is the average force? If it hits a soft surface for 0.1 seconds, what is the average force? Students calculate and write both forces.

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

Activity 04

• Problem-Based Learning
• 30 min · Whole Class

Helmet Demo: Fruit Impacts

Drop water-filled balloons or small fruits with and without helmet foam onto surfaces. Whole class observes cracking patterns and times impacts with stopwatches. Analyze why padding matters for head protection.

Why do playgrounds have soft surfaces?

What to look for

Present students with two scenarios: a cyclist falling onto asphalt and a cyclist falling onto grass. Ask them to write one sentence explaining which scenario would likely result in less force on the cyclist and why, referencing contact time.

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

A few notes on teaching this unit

Teach this topic by starting with the Egg Drop Lab so students experience the core idea firsthand. Avoid rushing to the formula; let students discover the relationship between time and force through measurement before introducing the impulse-momentum theorem. Research shows that students grasp impulse better when they first see the visual difference in collision durations.

Successful learning looks like students confidently linking padding to increased collision time and reduced force, not just memorizing the formula. You will see students using data from their tests to justify why certain materials protect better, and applying the impulse-momentum theorem to explain real-world safety designs.

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Watch Out for These Misconceptions

• During the Egg Drop Lab, students may think padding absorbs all kinetic energy and eliminates force entirely.

  During the Egg Drop Lab, remind students to check their force-time graphs; they will see lower peaks but not zero force, reinforcing that padding spreads out the force over time rather than eliminating it.

• During the Video Analysis, students may assume that the drop height alone determines the force of impact regardless of surface.

  During the Video Analysis, have students pause the clip at the moment of impact and measure the time to full stop on each surface; this visual evidence will show how soft surfaces extend collision time and reduce force.

• During the Toy Car Crash Test, students may believe thicker padding always provides more protection.

  During the Toy Car Crash Test, ask students to test stacked materials and plot force peaks; they will discover that beyond a certain thickness, rebound increases force again, showing that optimal protection requires balancing time and rebound.

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Methods used in this brief

• Problem-Based Learning