Science · Grade 2

Active learning ideas

Friction: The Stopping Force

Active learning works well for this topic because students need to feel friction in their hands and see its effects in motion. Building and testing devices lets them connect the concept to real movement and stopping, which makes abstract ideas concrete. The hands-on tasks also build persistence, as students learn that redesign is part of good design.

• Ontario Curriculum Expectations
• 2-PS1-1

• 20–60 min
• Pairs → Whole Class
• 3 activities

Activity 01

• Inquiry Circle
• 60 min · Small Groups

Inquiry Circle: The Great Cargo Move

Groups must design a way to move a 'heavy load' (a bag of marbles) across a 2-meter gap without touching the load directly. they must use at least two different simple machines in their design.

Explain how friction helps a car stop.

Facilitation Tip

During the Collaborative Investigation, provide only one type of material per team to limit choices and focus on function over decoration.

What to look for

Give students a toy car and two different surfaces (e.g., a smooth tile and a carpet square). Ask them to roll the car down a small ramp onto each surface and record how far it travels. On the ticket, they should write: 'Which surface made the car stop faster? Why?'

• Analyze
• Evaluate
• Create
• Self-Management
• Self-Awareness

Activity 02

• Think-Pair-Share
• 20 min · Pairs

Think-Pair-Share: The Redesign Phase

After a first round of testing their machines, students think about one thing that didn't work. They pair up with a member of another group to get a 'fresh pair of eyes' on their problem before going back to improve their design.

Compare the amount of friction on smooth and rough surfaces.

Facilitation Tip

Use a timer during the Think-Pair-Share phase so students practice concise explanations of their redesign steps.

What to look for

Ask students to stand up and pretend to ride a bicycle. Prompt them: 'Show me how you would use friction to stop your bike.' Observe if they demonstrate a pulling or squeezing motion, mimicking brake use.

• Understand
• Apply
• Analyze
• Self-Awareness
• Relationship Skills

Activity 03

• Gallery Walk
• 40 min · Whole Class

Gallery Walk: Engineering Expo

Once designs are complete, the class holds an 'expo.' Half the groups stay to demonstrate their machines while the other half rotates to ask questions and provide positive feedback on the designs.

Predict how friction will affect a toy car rolling down a ramp.

Facilitation Tip

Before the Gallery Walk, model how to ask specific questions such as, 'Which part of your device created the most friction?'

What to look for

Pose the question: 'Imagine you are designing a slide at a playground. Would you want a high friction surface or a low friction surface for the slide? Explain your choice using the word 'friction'.'

• Understand
• Apply
• Analyze
• Create
• Relationship Skills
• Social Awareness

A few notes on teaching this unit

Teach friction by letting students feel different textures first, then connect those feelings to movement. Avoid explaining friction too early; instead, let students notice it when their devices slow down or stop. Research shows that early failure followed by guided improvement builds deeper understanding than immediate success.

Successful learning looks like students using simple machines to slow or stop motion intentionally. They should explain why more friction helps stop objects and how their device meets the challenge. Listen for precise vocabulary like rough, smooth, push, pull, and brake when they describe their work.

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Watch Out for These Misconceptions

• During Collaborative Investigation: The Great Cargo Move, watch for students insisting their first design must work perfectly or they feel discouraged.

  Remind teams that every first try is a test, not a failure. Hand out sticky notes labeled 'Problem: ______' and ask students to write one issue they noticed after testing, then redesign using only three new pieces.

• During Think-Pair-Share: The Redesign Phase, watch for students overloading their devices with materials in hopes of a better result.

  Challenge students to remove half of their materials and rebuild a simpler version that still meets the goal, emphasizing function over quantity. Ask, 'Does this part help the cargo stop? If not, does it need to stay?'

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Methods used in this brief

• Inquiry Circle
• Think-Pair-Share
• Gallery Walk