Exploring Our World: Scientific Inquiry and Discovery · 3rd Year

Active learning ideas

Measuring Force

Students learn best about force when they feel it and see it in action, not just when they read about it. Designing hands-on experiments with spring scales and everyday objects helps students connect abstract concepts like Newtons to the tangible world of pushes and pulls they experience every day.

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

• 20–50 min
• Pairs → Whole Class
• 4 activities

Activity 01

• Problem-Based Learning
• 30 min · Pairs

Pairs: Object Lift Comparison

Pairs choose five classroom objects of different masses, such as erasers and books. Attach each to a spring scale and pull upward steadily at eye level, recording the newton reading. Compare results and discuss why heavier items show higher forces. Graph data to spot trends.

Explain how a spring scale measures the strength of a force.

Facilitation Tip

Before pairs begin Object Lift Comparison, circulate to ensure students hold the spring scale vertically and avoid side pulls, which skew readings.

What to look for

Provide students with a spring scale and two objects of different masses. Ask them to measure the force needed to lift each object steadily and record the measurement in Newtons. On the back, they should write one sentence explaining which object required more force and why.

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

Activity 02

• Problem-Based Learning
• 45 min · Small Groups

Small Groups: Surface Drag Stations

Set up stations with surfaces like table tops, sandpaper, and fabric. Groups drag a constant object using a spring scale, measure pull force needed to start motion, and rotate stations. Record averages after three trials per surface. Share findings in a class chart.

Design an experiment to compare the force needed to move different objects.

Facilitation Tip

At each Surface Drag Station, remind groups to keep the spring scale at a steady pace and record times to standardize pulling speed across trials.

What to look for

Present students with a scenario: 'Imagine you are designing a ramp for a toy car. What factors would affect the force needed to push the car up the ramp?' Guide them to discuss friction and the car's weight, prompting them to consider how they would measure these forces.

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

Activity 03

• Problem-Based Learning
• 50 min · Whole Class

Whole Class: Fair Test Design Challenge

Brainstorm variables affecting force, like object shape. Class votes on one, such as pulling blocks versus balls. Demonstrate consistent technique with spring scale. Students predict, test in pairs, and report data to evaluate test fairness.

Evaluate the importance of consistent measurement in scientific investigations.

Facilitation Tip

During the Fair Test Design Challenge, ask guiding questions like 'What will stay the same?' to help students isolate the variable they are testing.

What to look for

Show students a diagram of a spring scale with a weight attached. Ask: 'If the spring stretches further, does this mean the force is larger or smaller? Explain your answer using the term 'Newton'.'

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

Activity 04

• Problem-Based Learning
• 20 min · Individual

Individual: Force Diary

Each student measures forces for personal pushes or pulls, like opening doors or stretching rubber bands with a scale. Log readings with sketches. Compile into a class display to compare everyday forces.

Explain how a spring scale measures the strength of a force.

What to look for

Provide students with a spring scale and two objects of different masses. Ask them to measure the force needed to lift each object steadily and record the measurement in Newtons. On the back, they should write one sentence explaining which object required more force and why.

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

A few notes on teaching this unit

Teach this topic by letting students experience the challenges of measuring force firsthand before explaining theory. Avoid starting with definitions—instead, let them struggle with inconsistent readings due to friction or speed, then use those moments to introduce precise terms like 'Newton' and 'fair test.' Research shows these 'aha' moments stick better than direct instruction alone.

By the end of the activities, students should confidently use spring scales to measure force, explain how friction and mass affect force, and design fair tests to compare different scenarios. Success looks like clear data collection, thoughtful analysis, and accurate explanations tied to their observations.

---

Watch Out for These Misconceptions

• During the Object Lift Comparison activity, watch for students assuming that doubling the mass means doubling the force.

  After students measure the forces, have them compare the actual Newtons recorded and ask, 'Does doubling mass always mean double the force?' Use their data to guide a discussion on the role of friction and surface.

• During the Surface Drag Stations activity, watch for students thinking the spring scale measures weight rather than applied force.

  Ask pairs to lift an object vertically using the scale, then drag it horizontally. Have them compare the readings and explain why the numbers differ, reinforcing that the scale measures any push or pull.

• During the Fair Test Design Challenge, watch for students ignoring the impact of pulling speed on force readings.

  After trials, ask groups to describe how their pulling speed varied and how it might have affected results. Guide them to adjust their methods for more consistent trials in future tests.

---

Methods used in this brief

• Problem-Based Learning