Science · Grade 6

Active learning ideas

Types of Mixtures: Solutions, Suspensions, Colloids

Active learning helps students grasp the invisible differences between mixtures by making particle behavior tangible. When students create, observe, and separate mixtures themselves, they build lasting mental models of solutions, suspensions, and colloids that go beyond textbook definitions.

• Ontario Curriculum Expectations
• MS-PS1-1

• 25–45 min
• Pairs → Whole Class
• 4 activities

Activity 01

• Inquiry Circle
• 45 min · Small Groups

Lab Stations: Mixture Creation

Prepare stations for salt water (solution), sand water (suspension), and cornstarch water (colloid). Small groups mix ingredients, record initial appearance, then let sit for 10 minutes to check settling. Shine flashlights through each to test Tyndall effect.

Compare the characteristics of solutions, suspensions, and colloids.

Facilitation Tip

During Lab Stations: Mixture Creation, prepare exact measurements for each mixture so students focus on observations rather than recipe errors.

What to look for

Provide students with three labeled beakers containing water, salt water (solution), muddy water (suspension), and milk (colloid). Ask students to write down one observation for each beaker that helps them classify it as a solution, suspension, or colloid. Include one question: 'Which mixture would you need to shake before using and why?'

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

Activity 02

• Inquiry Circle
• 30 min · Pairs

Filtration Challenge: Pairs

Pairs filter samples of a solution, suspension, and colloid using coffee filters and funnels. Note residue on filters and clarity of filtrate. Discuss how particle size predicts results and sketch findings.

Design an experiment to distinguish between a solution and a suspension.

Facilitation Tip

In Filtration Challenge: Pairs, circulate with a timer to ensure teams record data consistently so comparisons are valid.

What to look for

Present students with images of various mixtures (e.g., clear juice, orange juice with pulp, fog, sand in water). Ask them to label each image as a solution, suspension, or colloid and provide one reason for their classification, focusing on particle visibility or settling.

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

Activity 03

• Inquiry Circle
• 40 min · Whole Class

Shake and Observe Demo: Whole Class

Demonstrate shaking jars of each mixture type, then observe settling over 20 minutes as a class. Students predict and time settling, then share data on class chart. Extend with student-led predictions for new mixtures.

Explain how particle size influences the properties of different mixtures.

Facilitation Tip

For Shake and Observe Demo: Whole Class, dim lights when testing for the Tyndall effect to make light scattering unmistakable.

What to look for

Pose the question: 'Imagine you are making a science fair project that requires separating components of a mixture. How would the type of mixture (solution, suspension, or colloid) influence the method you choose for separation?' Facilitate a class discussion comparing filtration, evaporation, and settling.

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

Activity 04

• Inquiry Circle
• 25 min · Individual

Particle Size Sort: Individual

Provide images or samples of particles from fine salt to sand. Individuals sort by estimated size, predict mixture type, then test one prediction by mixing. Compare results in plenary.

Compare the characteristics of solutions, suspensions, and colloids.

Facilitation Tip

During Particle Size Sort: Individual, provide a reference chart with visual particle sizes so students connect labels to real examples.

What to look for

Provide students with three labeled beakers containing water, salt water (solution), muddy water (suspension), and milk (colloid). Ask students to write down one observation for each beaker that helps them classify it as a solution, suspension, or colloid. Include one question: 'Which mixture would you need to shake before using and why?'

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

A few notes on teaching this unit

Teach this topic by starting with what students already know about mixtures, then layer in new vocabulary and tools like microscopes or flashlights. Avoid rushing to the terms solutions, suspensions, and colloids before students see the differences themselves. Research shows students learn best when they first manipulate materials, then name their observations, rather than memorizing definitions up front.

Successful learning looks like students confidently classifying mixtures by particle size, predicting behavior like settling or light scattering, and justifying choices with evidence from their hands-on work. Clear labeling, careful observations, and collaborative discussions show growing mastery of the distinctions.

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Watch Out for These Misconceptions

• During Lab Stations: Mixture Creation, watch for students assuming all mixtures settle over time.

  Ask students to predict which mixtures will settle before leaving the station, then have them time their jars and record results in a shared class table to compare outcomes.

• During Shake and Observe Demo: Whole Class, watch for students calling colloids solutions because they look uniform at first.

  Pass flashlights around so every student sees the Tyndall effect in colloids like milk or gelatin, then ask them to revise their labels as a class.

• During Filtration Challenge: Pairs, watch for students thinking particle size does not affect filtration.

  Have pairs compare filter papers after separating mixtures, then sketch the trapped particles to connect size to separation success.

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Methods used in this brief

• Inquiry Circle