Science · Grade 6

Active learning ideas

Sources of Water Pollution

Active learning helps students connect abstract pollution concepts to their own communities by making invisible processes visible. Hands-on mapping and simulations build spatial reasoning and systems thinking, which are essential for understanding how pollutants move through local watersheds.

• Ontario Curriculum Expectations
• MS-ESS3-3

• 30–45 min
• Pairs → Whole Class
• 4 activities

Activity 01

• Gallery Walk
• 45 min · Pairs

Mapping Activity: Local Watershed Audit

Provide maps of a nearby watershed. Students in pairs identify potential pollution sources like farms, roads, and factories, mark point and non-point locations, and draw pathways to water bodies. Discuss findings as a class and propose mitigation ideas.

Identify the primary sources of pollution in a local watershed.

Facilitation Tip

During the Mapping Activity, provide students with large laminated maps of their local watersheds to allow for repeated erasing and redrawing as they revise their pollution source placements.

What to look for

Present students with images of different scenarios (e.g., a factory pipe discharging into a river, a farmer's field after rain, litter on a street). Ask them to label each as either 'point source' or 'non-point source' pollution and briefly explain their reasoning.

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

Activity 02

• Gallery Walk
• 30 min · Small Groups

Demonstration: Point vs Non-Point Runoff

Create two model landscapes: one with a pipe (point source) dripping dye into a stream, another with sloped soil (non-point) where rain simulates runoff carrying 'pollutants'. Observe and compare how contaminants enter water. Groups record differences and clean-up challenges.

Explain how human activities on land affect the quality of water sources.

Facilitation Tip

For the Demonstration, use two separate trays labeled ‘point’ and ‘non-point’ to show students how to set up their runoff simulations clearly.

What to look for

Pose the question: 'Imagine a plastic bottle is dropped on a sidewalk in your neighbourhood. Describe the most likely pathway that bottle, or the chemicals it might contain, could take to reach a local lake or river.' Encourage students to use vocabulary like 'runoff' and 'watershed'.

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

Activity 03

• Gallery Walk
• 35 min · Whole Class

Role-Play: Pollution Pathway Simulation

Assign roles as raindrop, fertilizer particle, or fish. Students move through a simulated watershed, showing how pollutants travel from fields to lakes. Pause for discussions on barriers like wetlands. Debrief on prevention strategies.

Analyze the difference between point source and non-point source pollution.

Facilitation Tip

In the Role-Play, assign specific roles like ‘farmer,’ ‘factory worker,’ or ‘stormwater’ to ensure students embody different perspectives during the simulation.

What to look for

On an index card, have students list two common sources of water pollution they might find in their own community. For each source, they should identify if it is a point source or non-point source and explain one way it could enter a local water system.

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

Activity 04

• Gallery Walk
• 40 min · Individual

Data Analysis: Pollution Case Studies

Distribute charts of real Ontario incidents, like algal blooms from runoff. Individually analyze sources, impacts, and solutions, then share in small groups. Create posters summarizing key differences between source types.

Identify the primary sources of pollution in a local watershed.

What to look for

Present students with images of different scenarios (e.g., a factory pipe discharging into a river, a farmer's field after rain, litter on a street). Ask them to label each as either 'point source' or 'non-point source' pollution and briefly explain their reasoning.

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

A few notes on teaching this unit

Teachers often find that starting with familiar local examples, like a nearby farm or parking lot, helps students grasp the concept of non-point sources more readily than abstract factory images. Avoid overwhelming students with too many pollutants at once; focus on two or three key examples per activity to build confidence. Research suggests that using colored dyes or tracers in simulations makes pathways memorable and improves long-term retention of watershed connections.

Students will confidently distinguish point and non-point sources, trace pollutants through watersheds using local examples, and explain how human activities impact water quality. Successful learning includes accurate labeling, clear pathway descriptions, and thoughtful reflections on community impacts.

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Watch Out for These Misconceptions

• During the Demonstration: Point vs Non-Point Runoff, watch for students assuming all pollution must come from visible pipes or smokestacks.

  Use the two trays to show how non-point sources spread across large areas, then ask students to compare the concentrated flow in the ‘point’ tray to the diffuse spread in the ‘non-point’ tray.

• During the Demonstration: Point vs Non-Point Runoff, watch for students believing pollutants disappear quickly after entering water.

  Use food coloring or washable dye in the runoff trays to track movement, then have students observe how the dye persists and spreads downstream over time.

• During the Mapping Activity: Local Watershed Audit, watch for students attributing pollution primarily to natural events like storms.

  Have students highlight areas with impervious surfaces on their maps, then discuss how human development intensifies pollution during storms compared to natural landscapes.

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Methods used in this brief

• Gallery Walk