How Pushes and Pulls Change Movement

Active learning lets students feel force directly through their hands and see its effects in real time. When learners push or pull objects of different masses, they form lasting mental models of how force and mass interact to change movement, beyond abstract equations on paper.

• 5th Year
• Principles of the Physical World: Senior Cycle Physics
• 4 activities
• 30 min–45 min

Learning Objectives

1. Compare the acceleration of objects with different masses when subjected to the same applied force.
2. Calculate the force required to achieve a specific acceleration for an object of known mass.
3. Analyze the relationship between applied force, mass, and acceleration through graphical representation.
4. Explain how friction affects the motion of an object when a push or pull is applied.

Experiential Learning

⏱ 45 min·Small Groups

Trolley Push: Varying Forces

Provide trolleys of fixed mass on a low-friction track. Students use a Newton meter to apply three force strengths, measuring acceleration via light gates or stopwatch over 1m. Record data in tables, then graph force vs acceleration. Discuss trends as a class.

Prepare & details

What happens if you push a light toy car compared to a heavy one?

Facilitation Tip: During Trolley Push, remind students to keep friction surfaces consistent by testing each force push on the same marked path.

Setup: Varies; may include outdoor space, lab, or community setting

Materials: Experience setup materials, Reflection journal with prompts, Observation worksheet, Connection-to-content framework

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

Experiential Learning

⏱ 35 min·Pairs

Mass Variation: Toy Car Races

Set up ramps for toy cars of light, medium, heavy masses. Release from same height or give identical pushes, timing speed to finish line. Groups swap masses and repeat three times for averages. Compare results on class chart.

Prepare & details

How hard do you need to push a swing to make it go high?

Facilitation Tip: For Mass Variation races, have students record both mass and push force on a shared class chart to spot patterns across trials.

Setup: Varies; may include outdoor space, lab, or community setting

Materials: Experience setup materials, Reflection journal with prompts, Observation worksheet, Connection-to-content framework

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

Experiential Learning

⏱ 40 min·Small Groups

Swing Force Challenge: Pendulum Pushes

Use string pendulums with bob masses. Students give gentle, medium, strong initial pushes, measuring swing height or period with protractors and timers. Predict outcomes before testing, then verify with data.

Prepare & details

Can a small push make a big object move?

Facilitation Tip: In the Swing Force Challenge, ask each group to measure the angle of release and relate it to the push force needed to reach that height.

Setup: Varies; may include outdoor space, lab, or community setting

Materials: Experience setup materials, Reflection journal with prompts, Observation worksheet, Connection-to-content framework

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

Experiential Learning

⏱ 30 min·Whole Class

Whole Class Demo: Cart Pull Relay

Divide class into teams with carts of increasing mass. Each team pulls with fixed force over 5m, timing completion. Relay results to board for collective graph of mass vs time.

Prepare & details

What happens if you push a light toy car compared to a heavy one?

Facilitation Tip: For the Cart Pull Relay, assign roles so timers, pushers, and recorders work in quick rotation to sustain momentum and engagement.

Setup: Varies; may include outdoor space, lab, or community setting

Materials: Experience setup materials, Reflection journal with prompts, Observation worksheet, Connection-to-content framework

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

Teaching This Topic

Teachers often start with a quick demo showing two identical pushes on a light and heavy object, then ask students to predict which moves farther. Avoid explanations before trials; let students test their ideas first. Research shows that early prediction followed by observation builds stronger conceptual links than lecture alone.

What to Expect

By the end of these activities, students should confidently relate force magnitude, mass, and acceleration, explaining why a light object moves faster under the same push as a heavy one. They should use data from trials to support claims about inertia and net force.

Watch Out for These Misconceptions

Common Misconception

During Mass Variation: Toy Car Races, watch for students assuming the heaviest car will always finish last, even when pushed harder.

What to Teach Instead

Ask students to push each car with the same measured force and record distances. Have them compare results to see how force can overcome mass differences, prompting reflection on inertia.

Common Misconception

During Trolley Push: Varying Forces, watch for students believing any push makes an object speed up regardless of direction or existing motion.

What to Teach Instead

Set up a trolley moving toward a spring-loaded barrier and ask students to predict what happens when they push it forward or backward. Observe the change in speed and direction to clarify that forces alter velocity vectors.

Common Misconception

During Swing Force Challenge: Pendulum Pushes, watch for students using weight and mass interchangeably when predicting push strength.

What to Teach Instead

Have students weigh each pendulum bob and measure its mass separately. Ask them to push the same mass at different weights to observe that mass, not weight, determines resistance to acceleration.

Assessment Ideas

Quick Check

After Trolley Push: Varying Forces, give students a 3kg trolley pushed with 6N of force on a frictionless surface and ask them to calculate acceleration using F=ma. Collect answers to identify any confusion about the relationship between force, mass, and acceleration.

Discussion Prompt

During Mass Variation: Toy Car Races, pose the question: 'If you push a full shopping trolley and an empty one with the same effort, what differences do you see in how they move?' Circulate to listen for explanations that include mass and inertia.

Exit Ticket

After Swing Force Challenge: Pendulum Pushes, ask students to draw a pendulum bob with arrows showing a push force and the resulting acceleration direction. Have them write one sentence explaining how increasing the push force would change the acceleration.

Extensions & Scaffolding

• Challenge: Ask students to design a push that makes a 500g cart match the speed of a 200g cart pushed with 1N of force.
• Scaffolding: Provide a data table with columns for mass, push force, and distance traveled to guide students who struggle with independent recording.
• Deeper exploration: Have students calculate acceleration from time and distance data, then graph force versus acceleration for constant mass to introduce Newton’s Second Law visually.

Key Vocabulary

Force	A push or a pull that can cause an object to change its motion, shape, or size.
Mass	A measure of the amount of matter in an object; it is a property that resists acceleration.
Acceleration	The rate at which an object's velocity changes over time, indicating how quickly it speeds up, slows down, or changes direction.
Friction	A force that opposes motion between surfaces in contact, often converting kinetic energy into heat.