At a Glance


  • STEM
  • Physics

Instructional Level

  • College & CEGEP
  • University


  • Mechanics

Tasks in Workflow

Social Plane(s)

  • Individual
  • Group
  • Whole Class

Type of Tasks

  • Solving problems
  • Analyzing
  • Creating & designing
  • Writing
  • Presenting
  • Taking a quiz & test

Technical Details

Useful Technologies

  • Online collaborative platform
  • In class students can work on smartboards or whiteboards

Class size

  • Small (20-49)


  • Single class period (< 90 mins)

Instructional Purpose

  • Application & knowledge building
  • Assessment & knowledge refinement


In this activity, students will learn about Newton’s Third Law force pairs. Out of class, individual students will find an image of interest with two or more interacting objects. They will prepare free-body diagrams of the objects in the images and reflect on how the phrase “for every action, there is an equal and opposite reaction” applies to their image.

In class, students will be assigned to groups and each group will select a single image to work with. The groups will prepare free-body diagrams for the objects in the images, in both zero and non-zero acceleration, and will then present their results to the class for peer review. They will then compare and contrast the forces in the free-body diagrams. Finally they will prepare a short written heuristic on identifying Third Law force pairs.

This activity scaffolds the near transfer of concepts and deepens an understanding of 3rd Law force pairs.

Instructional Objectives

Students will be able to:

  • Compare images in accelerating and non-accelerating states
  • Identify Newton’s 3rd Law force pairs

Workflow & Materials


Activity Workflow

View on CourseFlow

Contributor's Notes

Chris Whittaker

Chris Whittaker

Dawson College, Montreal


By having the students select their own image, it situates the activity in their own world and deepens their engagement. This activity leverages group learning capacities and works at multiple levels of Bloom’s taxonomy (levels of cognition). Format of the activity scaffolds the near transfer of concepts and deepens an understanding of 3rd law force pairs.


A big challenge is getting students to model the actual object in a simplified way (abstraction). Also, getting students to build a rich heuristic. As is the case with most activities, finding and implementing an appropriate online collaborative platform (OCP) is challenging. If a single group has poor overall understanding, students can try to compensate by adding every detail they can find which is not the point of the activity and complicates the matter at hand.


Potentially add more emphasis on the abstraction process. The simplified free body diagram is vital to this activity so additional time can be spent illustrating how to simplify the images.

Applied Strategies


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