August 17th, 2016

This activity elicits student thinking about forces. Through the “four corners” activity, students are required to use evidence to support their argument.

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2.5 — Force: Four Corners (Optional)

App Features

The Playground Physics app is not required for this lesson.

Expected Activity Time

  • Total Activity Time: 45 minutes
  • Introduction: 10 minutes
  • Activity: 25 minutes
  • Explain: 10 minutes

Total Extension Time (optional): 45 minutes

  • Record a Video: 45 minutes

Materials and Prep

  • Force: Four Corners Worksheet
  • Sample golf putting videos (for example from YouTube).
  • Signs for room corners (Mark, Tania, Claire, Antonio).
  • iPad with Playground Physics app (Optional).


Introduction (10 minutes)

  • Have students silently read the worksheet Four Corners and individually think through their responses to the scenario on the worksheet.
  • Have students commit to an answer, and write down their explanation.

Activity (25 minutes)

  • Four Corners is an activity for prompting discussion about multiple-choice questions. In this activity, each corner of the room is designated with one of the answer options from the worksheet (Mark, Tania, Claire or Antonio). Start the activity by having each student move to the corner of the room that represents the answer that he/she thinks is right.
  • Have students in each corner discuss internally why they have chosen that answer.
  • Have students choose a representative from their corner to explain to the class why they think their answer is right, with the objective of convincing others that they are correct. Remind students to use evidence to show why they believe the answer they are supporting is the best answer.
  • Throughout the debate, the students have the opportunity to switch corners to reflect the things they have considered and discussed over the course of the conversation. As the facilitator, let the students make their arguments for who they agree with; students should do most of the talking. Be wary of peer pressure and encourage students who are unsure not to be persuaded without a sufficiently compelling argument. This activity can last a long time, so set a time limit beforehand so that you have enough time to complete the whole lesson.
  • Listen to how students talk about force and note what misconceptions they have about it. Some of this will be evident by which corners the students chose.
  • Although there is one correct answer and three incorrect answers, let students argue and don’t guide them in the correct direction.

Discussion (10 minutes)

  • Introduce students to the idea of unbalanced forces. Unbalanced forces explain why forces, such as someone hitting a golf ball with a club, can cause changes in motion. In this case the best answer is Mark.
  • Have the students go back to the worksheet and add to or edit what they wrote, reflecting on what they learned during the activity.
  • Remember to check the “Parking Lot” of questions at the end of the class period. Remove any questions that have been answered and have students add any new questions that may have come up.


Record a Video (45 minutes)

  • Have students record a video showing an example of an unbalanced force and a video showing an example of a balanced force.
  • Have students annotate their videos with push and pull stickers to indicate the forces present in the scene.

Answer Key

The best answer is Mark: The ball exerted a force on the club when the club hit it, but it wasn’t a big enough force to balance the larger force from the club. The ball will roll until friction slows it down.

Worksheet Previews

Screen Shot 2016-08-18 at 12.25.59 PM Screen Shot 2016-08-18 at 12.26.11 PM

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Big Idea

The purpose of this activity is for students to practice thinking through all of the forces acting on an object and what the resulting motion will be when forces are unbalanced. The “Four Corners” activity is designed to promote scientific reasoning and articulation of scientific thinking.

Learning Objectives

Students will use scientific reasoning to construct an argument and to explain data.

Standards Addressed


Crosscutting Concept: Patterns
Observed patterns of forms and events guide organization and classification, and they prompt questions about relationships and the factors that influence them.


Text Types and Purposes

CCSS.ELA-LITERACY.W.6,7,8.1: Write arguments to support claims with clear reasons and relevant evidence.

Comprehension and Collaboration

CCSS.ELA-LITERACY.SL.6,7,8.1: Engage effectively in a range of collaborative discussions (one-on-one, in groups, and teacher-led) with diverse partners on grade 6 topics, texts and issues, building on others’ ideas and expressing their own clearly.

CCSS.ELA-LITERACY.SL.6,7,8.3: Delineate a speaker’s argument and specific claims, distinguishing claims that are supported by reasons and evidence from claims that are not.


Standard 4: The Physical Setting

PS 5.1b: The motion of an object can be described by its position, direction of motion, and speed.

PS 5.1c: An object’s motion is the result of the combined effect of all forces acting on the object. A moving object that is not subjected to a force will continue to move at a constant speed in a straight line. An object at rest will remain at rest.


  • Force is an interaction between objects that causes a change in the motion of an object.
  • Newton’s Third Law of Motion explains that for every action, there is an equal and opposite reaction.
  • Force pairs (push/pull) are the two objects whose forces are acting on one another in equal strength and opposite directions. These forces can be in the form of a push or a pull.

Device Strategies

Single-device implementation

With only one device, you can project the iPad so that the entire class can watch and be involved in the recording and investigation/annotation of a single video.

Multiple-device implementation

With many devices, students may be broken up into teams to work collaboratively on their iPad to record, annotate and investigate their videos. Teams of three or four students  work well. Suggestions for student roles in each time can be found in the introduction.