Curious Investigators: Exploring Our World · 3rd Class

Active learning ideas

Melting and Freezing

Active learning builds lasting understanding of melting and freezing by letting students feel the temperature changes and see materials transform. When students handle real substances and watch them shift between solid and liquid, the abstract concepts become concrete and memorable.

• NCCA Curriculum Specifications
• NCCA: Primary - Materials

• 20–35 min
• Pairs → Whole Class
• 4 activities

Activity 01

• Inquiry Circle
• 35 min · Small Groups

Melting Race: Small Groups

Provide small groups with ice, butter, and chocolate pieces. Students predict melting order in identical warm water bowls, then time each substance and record results on charts. Groups share findings and explain differences.

Explain what happens to a substance when it melts or freezes.

Facilitation Tip

During Melting Race, set identical ice cube sizes and provide two timers so each group times its own melt at room temperature and in warm water.

What to look for

Provide students with three cards: 'Ice Cube', 'Butter', 'Chocolate'. Ask them to write one sentence for each card predicting if it will melt in their hand and why, based on what they learned about melting.

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

Activity 02

• Inquiry Circle
• 30 min · Pairs

Freezing Mixtures: Pairs

Pairs mix water with salt or sugar, predict freezing times in ice trays placed in freezer. Check after 20 minutes, observe differences, and discuss why pure water freezes faster. Extend by remelting samples.

Compare the melting points of different materials.

Facilitation Tip

When pairs conduct Freezing Mixtures, ask them to record start times and temperatures to connect observations with measurable data.

What to look for

Show students a video clip of ice melting in a warm room and water freezing in a freezer. Ask them to verbally identify the processes occurring and state one observation about how the substance changed.

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

Activity 03

• Inquiry Circle
• 25 min · Whole Class

Temperature Prediction Walk: Whole Class

As a class, list classroom objects and predict if they melt or freeze at room temperature. Test select safe items like crayons or lotion, vote on outcomes, then verify with observations and class discussion.

Predict whether a substance will melt or freeze at a given temperature.

Facilitation Tip

For Ice Cube Variables, give each student a recording sheet with columns for weight, shape, and temperature so they practice careful data collection.

What to look for

Pose the question: 'If you put a cup of water outside on a very cold winter day, what do you think will happen to it? Will it melt or freeze? How do you know?' Encourage students to use the terms melting, freezing, and temperature in their answers.

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

Activity 04

• Inquiry Circle
• 20 min · Individual

Ice Cube Variables: Individual

Each student tests one ice cube in plain water, salt water, or under fan. Time melting, note conditions, and report to class. Compile data to identify fastest melt.

Explain what happens to a substance when it melts or freezes.

Facilitation Tip

In Temperature Prediction Walk, pause at each station to ask students to justify their predictions using the word ‘temperature’ in a complete sentence.

What to look for

Provide students with three cards: 'Ice Cube', 'Butter', 'Chocolate'. Ask them to write one sentence for each card predicting if it will melt in their hand and why, based on what they learned about melting.

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

A few notes on teaching this unit

Teachers approach melting and freezing by starting with familiar objects like ice and chocolate, then moving to careful measurements. Avoid rushing to explanations; instead, let students notice patterns and ask questions first. Research shows that hands-on repetition with different materials builds stronger conceptual change than lectures alone.

Students will confidently identify melting and freezing, explain that mass is conserved during these changes, and predict outcomes based on temperature differences. They will use accurate vocabulary and share clear observations with peers.

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Watch Out for These Misconceptions

• During Ice Cube Variables, watch for students who believe the melted water has less mass than the ice cube.

  Ask students to weigh their ice cube before and after melting using a simple balance scale, then compare group results to confirm the mass stays the same.

• During Melting Race, watch for students who think chocolate and ice melt at the same speed because they are both solids.

  Have groups compare their timing data for ice and chocolate, then prompt them to explain why different materials melt at different rates.

• During Freezing Mixtures, watch for students who believe frozen wax cannot melt again.

  Let students melt the wax with gentle heat, then refreeze it, and ask them to describe how this shows freezing is reversible.

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Methods used in this brief

• Inquiry Circle