Mathematics · Year 2

Active learning ideas

Comparing and Ordering Capacity (Informal Units)

Active learning works because students grasp capacity through physical actions, not abstract talk. When children pour, scoop, and compare with their own hands, they build mental models that match the concept’s real meaning.

• ACARA Content Descriptions
• AC9M2M01

• 20–50 min
• Pairs → Whole Class
• 4 activities

Activity 01

• Stations Rotation
• 45 min · Small Groups

Stations Rotation: Capacity Stations

Prepare stations with pairs of containers like jars, cups, and bottles. Students fill using informal units such as small cups of water or sand, compare which holds more, and record with drawings. Rotate groups every 10 minutes, then share findings.

How can we compare the capacity of two different shaped containers?

Facilitation Tip

During Capacity Stations, circulate with a checklist to note which pairs still confuse width with capacity before moving on.

What to look for

Present students with two different-shaped containers and a collection of small blocks. Ask: 'Which container do you think holds more blocks? Now, fill both containers with blocks. Which one actually holds more? How do you know?' Observe their reasoning and use of vocabulary.

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

Activity 02

• Experiential Learning
• 30 min · Pairs

Pairs Challenge: Mystery Containers

Give pairs opaque bags with containers of varying capacities. They predict order by shaking or feeling, then fill with rice to compare and order from least to most. Discuss why shapes tricked their guesses.

Explain why filling containers with water or sand helps us understand capacity.

What to look for

Give each student a card with a drawing of three containers labeled A, B, and C. Ask them to write one sentence ordering the containers from 'holds least' to 'holds most' based on a demonstration or prior activity. For example: 'Container A holds less than B, and B holds less than C.'

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

Activity 03

• Experiential Learning
• 50 min · Whole Class

Whole Class: Design Your Test

Pose the key question on comparing shapes. Students design experiments using classroom items, test in groups, and vote on the container holding most. Chart results and explain methods.

Design an experiment to prove which container holds the most liquid.

What to look for

After an activity comparing capacity using scoops of water, ask: 'Why did we use the same scoop for all the containers? What would happen if we used a bigger scoop for one container and a smaller scoop for another? How would that change our results?'

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

Activity 04

• Experiential Learning
• 20 min · Individual

Individual: Capacity Journal

Each student selects three containers, fills with buttons or water using a standard spoon, sketches comparisons, and labels 'more', 'less', or 'same'. Share one surprising result.

How can we compare the capacity of two different shaped containers?

What to look for

Present students with two different-shaped containers and a collection of small blocks. Ask: 'Which container do you think holds more blocks? Now, fill both containers with blocks. Which one actually holds more? How do you know?' Observe their reasoning and use of vocabulary.

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

A few notes on teaching this unit

Teach this topic by letting students experience the mismatch between appearance and reality. Avoid explaining too soon—let the evidence from their pouring and counting guide their understanding. Research shows that when students confront their own predictions that fail, learning sticks more deeply.

Success looks like students using accurate language to compare containers, such as ‘holds more’ or ‘holds less,’ and revising their guesses after measuring. They should explain their choices with evidence from their trials, not just appearance.

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Watch Out for These Misconceptions

• During Capacity Stations, watch for students assuming a wider container holds more without testing.

  Prompt them to fill both containers with the same unit and compare the counts, then ask, ‘What did you notice about the number of units?’

• During Mystery Containers, watch for students assuming two identical-looking containers hold the same amount.

  Have them fill each with an informal unit and count aloud, then ask, ‘Why do two containers that look the same hold different numbers of scoops?’

• During Design Your Test, watch for students counting units without focusing on the container’s capacity.

  Redirect by asking, ‘Which container needed more scoops? What does that tell you about its space inside?’

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Methods used in this brief

• Stations Rotation
• Experiential Learning