Forces at Work


Duration: 60 minutes

Notes / Activity


Effects of forces challenges

  • 3-PS2-1: Plan and conduct an investigation to provide evidence of the effects of balanced and unbalanced forces on the motion of an object. [Clarification Statement: Examples could include an unbalanced force on one side of a ball can make it start moving; and, balanced forces pushing on a box from both sides will not produce any motion at all.] [Assessment Boundary: Assessment is limited to one variable at a time: number, size, or direction of forces. Assessment does not include quantitative force size, only qualitative and relative. Assessment is limited to gravity being addressed as a force that pulls objects down.]

By the end of this lesson, the student should able to:

  • Design and develop a tool/model to demonstrate a push or a pull. 

Lesson Plan

Lesson Introduction

Duration: 10 min

  • Have students identify objects to push and pull around them to solve a problem, such as pushing and pulling doors, chairs, books, and desks.
  •  Have each student demonstrate pushing and pulling an object such as a door, drawer, chair, or book.
  • Discuss how the force of the push or pull causes each object to change motion, direction, or speed. 
  • Discuss how motion and speed of an object are affected by the strength of a push or pull.


Duration: 50 min

Prepare the following materials before the lesson:

  • Pipe Cleaners
  • Coloured Ice cream sticks
  • Pipe Cleaners
  • Coloured Ice cream sticks
  • Present a problem to the students. 


E.g. Design a tool to move the animals around the farm without falling off.


  • Have the students think of how they will create their tool using the materials provided 
  • Make sure to elicit whether the tool uses a push or pull to move the lambs around in the barn. 


For example, students show that they are pushing the animals with the tool, teachers will ask “Is this a push or pull?”


  • Students will present and share their tools.
  • Discuss and elicit from students and ask them to compare different models/suggestions:


How is your model/design effective in moving the animals around the farm?

How is this model better than the other model?


  • Have students modify their tool/structure to make it more effective in transporting the animals – for example, can the tool be moved in all directions?
  • Get them to draw their design on paper. 
  • Share and present their ideas. 
  • Have students start building their model/structure/design.
  • Get students to test their models and see if they are able to move the animals without falling. 
  • Share and present their models. 
  • Evaluate its effectiveness and suggest modification to improve the design.
  • Have students make modifications to their model and let them test it again. 
  • Elicit from students:


What do you think are some forces acting on the tool when you are moving it?


  • Conclude the lesson by launching a learning story to have students explore the different types of forces at work. 
  • Elicit from students:


What are some forces we experience in our daily lives? (Gravitational force, Frictional force)