Science · Grade 6

Active learning ideas

Pure Substances vs. Mixtures

Active learning works because classifying materials by properties is a tactile skill. Students need to touch, observe, and manipulate substances to see how uniform composition or variable parts shape classification. These activities move beyond definitions to concrete, memorable evidence.

• Ontario Curriculum Expectations
• MS-PS1-1

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

Activity 01

• Stations Rotation
• 35 min · Small Groups

Sorting Stations: Material Classification

Prepare stations with samples like sugar water, sand, salt, and distilled water. Students observe properties such as settling or uniform texture, then classify as pure or mixture and record evidence. Groups rotate stations, comparing notes at the end.

Differentiate between a pure substance and a mixture using observable properties.

Facilitation Tip

During Sorting Stations, provide magnifying lenses for students to check uniformity closely before deciding.

What to look for

Present students with a tray of common materials (e.g., a beaker of salt water, a piece of granite, a sample of pure iron filings, a glass of air). Ask students to write down each item and classify it as a pure substance or mixture, listing one observable property that supports their choice.

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

Activity 02

• Stations Rotation
• 45 min · Pairs

Separation Lab: Extract Components

Pairs mix sand with water and salt with water. They filter the sand mixture and evaporate the salt solution, observing how components return unchanged. Discuss how this proves physical separation unlike chemical changes.

Analyze how the properties of a mixture compare to the properties of its individual components.

Facilitation Tip

In Separation Lab, circulate to ask each group to predict what will remain after evaporation before they heat the sample.

What to look for

Pose the question: 'Imagine you have a glass of lemonade. Is it a pure substance or a mixture? How do you know?' Facilitate a class discussion where students use vocabulary like 'uniform composition' and 'individual properties' to justify their answers.

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

Activity 03

• Stations Rotation
• 40 min · Small Groups

Property Comparison Chart: Test and Tabulate

Provide materials like air (balloon), water, oil, and syrup. Small groups test solubility in water, magnetism, or density layering, charting if properties match pure uniformity or component blend. Share charts whole class.

Justify why water is considered a pure substance while air is a mixture.

Facilitation Tip

For Property Comparison Chart, model how to record data with one example on the board before students begin.

What to look for

Give each student a card with the name of a substance (e.g., 'Gold', 'Saltwater', 'Air', 'Water'). Ask them to write one sentence explaining whether it is a pure substance or a mixture and one reason why, referencing its composition or properties.

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

Activity 04

• Stations Rotation
• 30 min · Whole Class

Justification Debate: Water vs Air

Whole class divides into teams. One argues water as pure using boiling tests, the other air as mixture via gas models or candle experiments. Vote with evidence after structured talks.

Differentiate between a pure substance and a mixture using observable properties.

Facilitation Tip

During Justification Debate, assign roles like 'data keeper' or 'property recorder' to keep students accountable.

What to look for

Present students with a tray of common materials (e.g., a beaker of salt water, a piece of granite, a sample of pure iron filings, a glass of air). Ask students to write down each item and classify it as a pure substance or mixture, listing one observable property that supports their choice.

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

A few notes on teaching this unit

Start with a quick demonstration of a pure substance versus a mixture to anchor vocabulary. Avoid overusing slides; instead, let students discover patterns through structured exploration. Research shows that when students generate their own evidence, misconceptions fade faster than when teachers explain them away.

Successful learning looks like students using observable traits such as boiling point consistency or visible separation to justify pure substances versus mixtures. They should explain their reasoning with examples drawn from their own data and observations at each station.

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Watch Out for These Misconceptions

• During Sorting Stations, watch for students labeling all clear liquids as pure substances.

  Ask groups to predict whether saltwater will leave a residue after evaporation and test it in the Separation Lab to see salt crystals reappear, showing it is a mixture despite its uniform appearance.

• During Property Comparison Chart, watch for students assuming mixtures always show visible separate parts.

  Use the chart to record observations of food coloring dissolving in water, then have students magnify the solution to see uniformity while discussing how air or brass are mixtures without visible separation.

• During Separation Lab, watch for students believing adding anything to water permanently changes its purity.

  After filtering sand from water, ask pairs to explain how the water returns to its original clear state, reinforcing that mixtures separate physically and do not form new substances.

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Methods used in this brief

• Stations Rotation