Science · Year 5

Active learning ideas

The Science of Dissolving

Active learning helps Year 5 students grasp the invisible process of dissolving by making particle behavior visible through hands-on experiments. When students measure, observe, and compare changes in real time, they connect abstract science concepts like conservation of mass to tangible outcomes they can see and touch.

• National Curriculum Attainment Targets
• NC-KS2-Science-Y5-PCM-4

• 20–45 min
• Pairs → Whole Class
• 4 activities

Activity 01

• Inquiry Circle
• 30 min · Pairs

Fair Test: Temperature Effects

Provide cups of cold, warm, and hot water with identical sugar amounts. Pairs time how long each takes to dissolve fully, stirring consistently. They record times and discuss patterns in a class chart.

Explain where a solid goes when it dissolves into a liquid.

Facilitation Tip

During the Fair Test: Temperature Effects activity, set the room temperature to 20°C to ensure a consistent baseline before adding hot or cold water.

What to look for

Provide students with three scenarios: 1) Sugar in tea, 2) Sand in water, 3) Salt in cooking oil. Ask them to identify which is a solution, which is a mixture, and explain why for each.

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

Activity 02

• Stations Rotation
• 45 min · Small Groups

Stations Rotation: Solutes and Solvents

Set up stations with salt, sugar, flour in water, oil, and vinegar. Small groups test dissolving at each, noting clarity and filtering attempts. Rotate every 7 minutes and share findings.

Analyze how temperature and stirring affect the rate of dissolving.

Facilitation Tip

In the Station Rotation: Solutes and Solvents activity, provide each group with a magnifying lens to inspect undissolved solute particles before and after stirring.

What to look for

Show students two identical beakers, one with cold water and one with hot water. Add the same amount of salt to each. Ask: 'Which beaker do you predict will dissolve the salt faster? Explain your reasoning using the terms solute, solvent, and temperature.'

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

Activity 03

• Inquiry Circle
• 25 min · Individual

Mixture vs Solution Challenge

Individuals mix sand-water and salt-water, then filter both. They observe residues, taste tests if safe, and classify each as mixture or solution in notebooks.

Differentiate between a mixture and a solution using examples.

Facilitation Tip

During the Mixture vs Solution Challenge, remind students to label their filters with the solute name so they can track which mixtures separate and which do not.

What to look for

Pose the question: 'Imagine you are making lemonade. You add lemon juice (solute) to water (solvent). What happens to the lemon juice? Is the lemonade a solution or a mixture? How would stirring affect the process?'

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

Activity 04

• Inquiry Circle
• 20 min · Whole Class

Stirring Speed Test

Whole class tests one spoon of coffee in water: no stir, slow stir, fast stir. Time dissolving and vote on fastest method before revealing results.

Explain where a solid goes when it dissolves into a liquid.

Facilitation Tip

In the Stirring Speed Test activity, use a metronome app on a shared device to standardize stirring speeds across groups for fair comparison.

What to look for

Provide students with three scenarios: 1) Sugar in tea, 2) Sand in water, 3) Salt in cooking oil. Ask them to identify which is a solution, which is a mixture, and explain why for each.

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

A few notes on teaching this unit

Teach dissolving by moving from concrete to abstract. Start with observable changes in mixtures and solutions, then introduce the particle model to explain why mass is conserved. Avoid rushing to the model before students see the evidence. Research shows students grasp particle behavior better when they first experience the effects of stirring and temperature, then connect those effects to particle movement.

Students will confidently explain why mass is conserved when solids dissolve and describe how temperature and stirring affect dissolving rates. They will also accurately differentiate solutions from mixtures using evidence from their tests and observations.

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Watch Out for These Misconceptions

• During the Fair Test: Temperature Effects activity, watch for students interpreting the disappearance of solute as a loss of mass.

  Have students weigh the solute and solvent before and after dissolving, using the same balance for both measurements. Ask them to compare their results with their prediction and discuss why the combined mass did not change.

• During the Station Rotation: Solutes and Solvents activity, watch for students assuming all solutes dissolve completely into clear solutions.

  After students stir their samples, ask them to hold their solutions up to a light source and compare clarity. Then, show them how to filter sand water to reveal that not all mixtures dissolve.

• During the Stirring Speed Test activity, watch for students believing stirring only mixes and does not speed up dissolving.

  Ask students to compare their timers and observations from slow versus fast stirring. Have them describe how more frequent collisions between particles, as seen in faster stirring, speed up the dissolving process.

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Methods used in this brief

• Inquiry Circle
• Stations Rotation