## At a Glance

• Physics

#### Instructional Level

• College & CEGEP
• University

• Mechanics

#### Social Plane(s)

• Individual
• Group
• Whole Class

• 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)

#### Time

Single class period (< 90 mins)

#### Instructional Purpose

• Assessment & knowledge refinement
• Application & knowledge building

• Array
• Array

## Overview

Out of class, individual students find an image of interest with two or more interacting objects. They prepare free-body diagrams of the objects in the images. Both the images and free-body diagrams are uploaded to an online collaborative platform. They write a short reflective piece on how the phrase "for every action, there is an equal and opposite reaction" applies to their image.

In class, students are assigned to groups; each group selects a single image that has been uploaded to work with. The groups prepare free-body diagrams for the objects in the images in the case when acceleration is ...

Out of class, individual students find an image of interest with two or more interacting objects. They prepare free-body diagrams of the objects in the images. Both the images and free-body diagrams are uploaded to an online collaborative platform. They write a short reflective piece on how the phrase "for every action, there is an equal and opposite reaction" applies to their image.

In class, students are assigned to groups; each group selects a single image that has been uploaded to work with. The groups prepare free-body diagrams for the objects in the images in the case when acceleration is zero. They then present their results to the class for peer review. The groups prepare free-body diagrams for the objects in the case when acceleration is non-zero. They write a statement comparing and contrasting the forces in the free-body diagrams in two cases of zero and non-zero acceleration. Finally they prepare a short written heuristic on identifying 3rd Law force pairs.

Finally, the groups present their free-body diagrams, statements and heuristics to the entire class for peer review and feedback from the instructor.

## Instructional Objectives

The objective of this activity is to understand and identify 3rd Law force pairs. Students prepare free-body diagrams from relevant images they have selected and then compare them in the accelerating and non-accelerating state.

## Contributor's Notes

Chris Whittaker

Dawson College, Montreal, QC

### Benefits

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.

### Challenges

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.

### Tips

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.

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