Science · Year 5

Active learning ideas

Separating Mixtures: Evaporation

Active learning helps Year 5 students grasp evaporation’s role in separating mixtures by letting them observe real changes over time. Hands-on experiments make abstract ideas—like water becoming vapor and solids remaining—tangible and memorable, especially when students see their own results instead of just reading about them.

• National Curriculum Attainment Targets
• NC-KS2-Science-Y5-PCM-5

• 30–50 min
• Pairs → Whole Class
• 4 activities

Activity 01

• Inquiry Circle
• 45 min · Small Groups

Fair Test: Evaporation Rates

Provide saltwater in shallow dishes. Students place dishes in sun, shade, and by a fan, measuring water level daily with rulers. They record data in tables and graph results to compare rates.

Explain how evaporation can be used to recover a dissolved solid.

Facilitation Tip

During Fair Test: Evaporation Rates, remind students to measure volumes precisely with graduated cylinders to ensure their comparisons are valid.

What to look for

Students are given a small beaker containing a saltwater solution. They are asked to draw and label what they expect to see after the water has completely evaporated. They should also write one sentence explaining why the solid material is left behind.

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

Activity 02

• Stations Rotation
• 50 min · Small Groups

Stations Rotation: Salt Recovery

Set up stations with saltwater solutions of varying concentrations. Groups heat gently on hot plates or use sunlight to evaporate, then weigh recovered salt. Rotate stations, noting differences in yield.

Analyze the limitations of using evaporation for all types of mixtures.

Facilitation Tip

In Station Rotation: Salt Recovery, circulate with a checklist to note which groups correctly identify that only dissolved solids remain after evaporation.

What to look for

Present students with three different mixtures: sand and water, salt and water, and oil and water. Ask them to identify which mixture can be separated by evaporation and explain their reasoning for each. They should justify why evaporation works for one but not the others.

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

Activity 03

• Inquiry Circle
• 40 min · Pairs

Design Challenge: Quick Evaporation

Pairs design setups to evaporate saltwater fastest, using trays, cloths, or heat sources safely. Test predictions, measure time to dryness, and present best method to class.

Design an experiment to recover salt from a saltwater solution.

Facilitation Tip

For Design Challenge: Quick Evaporation, provide timers and thermometers so students collect measurable data to support their claims.

What to look for

Pose the question: 'Imagine you need to recover pure water from a saltwater solution. Would evaporation be the best method? Why or why not? What are the advantages and disadvantages of using evaporation compared to other separation techniques you know?'

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

Activity 04

• Inquiry Circle
• 30 min · Individual

Observation Journal: Classroom Drying

Students spill saltwater drops on paper or saucers around the room. Over a week, they journal daily changes, sketching crystals and linking to evaporation theory.

Explain how evaporation can be used to recover a dissolved solid.

Facilitation Tip

In Observation Journal: Classroom Drying, model how to record daily changes with both sketches and written observations to build consistency across groups.

What to look for

Students are given a small beaker containing a saltwater solution. They are asked to draw and label what they expect to see after the water has completely evaporated. They should also write one sentence explaining why the solid material is left behind.

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

A few notes on teaching this unit

Teach evaporation by starting with what students already know about water disappearing, then connecting it to separating mixtures. Avoid rushing to conclusions; let students test their own hypotheses first. Research suggests that students learn best when they see both successful and failed attempts, so plan for controlled comparisons and guided reflection. Focus on the reversibility of the process to reinforce conservation of mass, a concept students often find challenging.

Students will confidently link evaporation to dissolving solids, predict outcomes for different mixtures, and explain why some mixtures cannot be separated this way. They will also plan fair tests, collect data, and justify their methods using scientific reasoning rather than guesswork.

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Watch Out for These Misconceptions

• During Station Rotation: Salt Recovery, watch for students who assume evaporation works for all mixtures, including sand and water.

  Have students test a sand-water mixture at one station and observe that sand remains mixed rather than forming crystals. During the group discussion, ask them to classify the mixture as soluble or insoluble before deciding on a separation method.

• During Observation Journal: Classroom Drying, watch for students who believe the salt disappears or changes into something else.

  Ask students to weigh the dish before and after evaporation, then compare results in a class table. Use the data to discuss how mass is conserved and the salt remains chemically unchanged, just in crystal form.

• During Fair Test: Evaporation Rates, watch for students who think faster heating always produces more salt crystals.

  Have groups compare gentle heat with direct strong heat and measure the amount of salt recovered. In the plenary, graph the results together to show that splattering reduces yield, linking energy input to practical outcomes.

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Methods used in this brief

• Inquiry Circle
• Stations Rotation