Science · Year 2

Active learning ideas

Melting and Freezing

Active learning works well for melting and freezing because students need to see, touch, and time these changes themselves. Hands-on trials let them feel the temperature difference, observe the moment of phase change, and compare results side-by-side, which builds lasting understanding.

• ACARA Content Descriptions
• AC9S2U04

• 25–40 min
• Pairs → Whole Class
• 4 activities

Activity 01

• Plan-Do-Review
• 30 min · Small Groups

Prediction Challenge: Melting Race

Students predict and rank which melts fastest: ice cube, butter pat, chocolate square. Place items on plates in a warm spot, time changes every 2 minutes, and record with drawings or tallies. Groups discuss surprises and revise predictions.

Explain how adding heat changes ice into water.

Facilitation Tip

During the Melting Race, remind students to start timers at the same moment and place identical amounts of each material on the same surface.

What to look for

Provide students with a small ice cube and a piece of chocolate. Ask them to draw what each looks like at the start and then again after 5 minutes. Ask: 'Which one is melting faster and why?'

• Remember
• Apply
• Analyze
• Self-Management
• Decision-Making
• Self-Awareness

Activity 02

• Plan-Do-Review
• 40 min · Pairs

Freeze Test Stations

Set up stations with water in trays: plain, salted, different volumes. Students predict freeze times, place in freezer, check after 2 hours or next day, and compare results on class chart. Rotate stations for multiple trials.

Compare the time it takes for different materials to melt.

Facilitation Tip

At Freeze Test Stations, circulate with a timer to prompt groups to check every two minutes and record the first sign of freezing.

What to look for

Give students a card with a picture of ice and a picture of water in a freezer. Ask them to write one sentence describing what will happen to the ice in the freezer and one sentence explaining why.

• Remember
• Apply
• Analyze
• Self-Management
• Decision-Making
• Self-Awareness

Activity 03

• Plan-Do-Review
• 25 min · Pairs

Hand Heat Experiment

Give each pair ice cubes and chocolate pieces. Hold one in hand, keep one cool; observe and time melting. Record differences, then explain why heat from body speeds change. Share findings whole class.

Predict what happens to liquid water when it is placed in a freezer.

Facilitation Tip

In the Hand Heat Experiment, ask students to hold their hands still and time the first softening of chocolate to ensure fair comparisons.

What to look for

Show students a video clip of ice melting on a sunny day and water freezing in a freezer. Ask: 'What is happening to the water in each situation? What is making the water change?'

• Remember
• Apply
• Analyze
• Self-Management
• Decision-Making
• Self-Awareness

Activity 04

• Plan-Do-Review
• 35 min · Individual

Reversible Change Cycle

Students melt ice in warm water, pour into trays to refreeze, and observe full cycle. Draw before/after sketches and note time per step. Discuss if material changed identity.

Explain how adding heat changes ice into water.

Facilitation Tip

While running the Reversible Change Cycle, label each cup clearly so students can track the same water through melting and refreezing steps.

What to look for

Provide students with a small ice cube and a piece of chocolate. Ask them to draw what each looks like at the start and then again after 5 minutes. Ask: 'Which one is melting faster and why?'

• Remember
• Apply
• Analyze
• Self-Management
• Decision-Making
• Self-Awareness

A few notes on teaching this unit

Teach this topic through cycles of prediction, observation, and explanation. Begin with a quick prediction challenge to surface misconceptions, then move to structured experiments where students control variables and measure outcomes. Avoid long lectures; use short, focused discussions after each trial to reinforce the link between heat energy and particle movement. Research shows that students grasp reversible change more deeply when they physically manipulate materials and see immediate results.

Successful learning looks like students predicting outcomes, collecting data over time, and explaining their results with evidence. They should confidently describe which material melts faster and why, and recognize that freezing reverses melting without creating a new substance.

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Watch Out for These Misconceptions

• During the Prediction Challenge: Melting Race, watch for students who say the ice or chocolate is disappearing. Redirect them by having them weigh or measure volume before and after to see that the material is still there in a new form.

  After the race, ask groups to report the starting and ending weights or volumes. Use this evidence to clarify that melting changes form but keeps the same amount of material.

• During Prediction Challenge: Melting Race, watch for students who assume all solids melt at the same speed or temperature. Redirect them by comparing timed observations of different materials side-by-side.

  Prompt students to create a class chart showing how long each item took to melt. Discuss why ice melts faster than chocolate at room temperature, linking this to real-world examples like butter on toast.

• During Freeze Test Stations, watch for students who think freezing creates a new substance. Redirect them by using colored or flavored water before freezing so they see the same water turning solid.

  Ask students to predict what will happen to the color or flavor after freezing and then observe it. Use this to emphasize that freezing is the reverse of melting and does not change the material.

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Methods used in this brief

• Plan-Do-Review