Evaporation and Condensation

Active learning works for this topic because evaporation and condensation happen in everyday moments that students notice but rarely explain. By measuring puddles, observing bags of vapour, and testing glass surfaces, students connect abstract gas–liquid changes to tangible experiences they can touch, time, and talk about.

• Year 2
• Science
• 4 activities
• 20 min–45 min

Learning Objectives

1. Explain how heat causes liquid water to change into water vapor during evaporation.
2. Identify the role of cooling in transforming water vapor back into liquid water through condensation.
3. Construct a model that demonstrates the processes of evaporation and condensation within a closed system.
4. Analyze why puddles disappear more quickly on a warm, windy day compared to a cool, still day.

Experiential Learning

⏱ 30 min·Small Groups

Outdoor Hunt: Puddle Measurements

Students find school puddles, outline with chalk, and measure length and width at start, midday, and end. Note sun, wind, and shade effects in notebooks. Groups compare data to identify patterns.

Prepare & details

Analyze how puddles disappear on a sunny day.

Facilitation Tip: During Outdoor Hunt: Puddle Measurements, prompt students to read their rulers at consistent intervals so comparisons across groups are meaningful.

Setup: Varies; may include outdoor space, lab, or community setting

Materials: Experience setup materials, Reflection journal with prompts, Observation worksheet, Connection-to-content framework

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

Stations Rotation

⏱ 45 min·Small Groups

Stations Rotation: Evaporation Conditions

Prepare trays of water: one in sun, one shaded, one fanned, one still. Rotate groups every 10 minutes to measure water levels hourly. Predict and record which dries fastest.

Prepare & details

Explain the process of condensation on a cold glass.

Facilitation Tip: During Station Rotation: Evaporation Conditions, rotate student roles at each station so everyone handles the thermometer and fan at least once.

Setup: Tables/desks arranged in 4-6 distinct stations around room

Materials: Station instruction cards, Different materials per station, Rotation timer

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

Experiential Learning

⏱ 20 min·Pairs

Condensation Bags: Cooling Vapour

Fill clear plastic bags halfway with hot water, seal, and tape to windows. Observe droplets forming inside as vapour condenses. Wipe and repeat with ice inside to speed it up; draw changes.

Prepare & details

Construct a model to demonstrate the water cycle's evaporation and condensation stages.

Facilitation Tip: During Condensation Bags: Cooling Vapour, ask students to predict droplet size before tilting the bag so they connect their prediction to the outcome.

Setup: Varies; may include outdoor space, lab, or community setting

Materials: Experience setup materials, Reflection journal with prompts, Observation worksheet, Connection-to-content framework

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

Experiential Learning

⏱ 25 min·Whole Class

Whole Class Demo: Glass Mystery

Place cold glasses amid classroom steam from hot water bowls. Students predict and watch condensation form, then wipe and retest. Discuss why it happens on cold surfaces.

Prepare & details

Analyze how puddles disappear on a sunny day.

Facilitation Tip: During Whole Class Demo: Glass Mystery, invite students to feel the temperature difference between the outside and inside of the glass to reinforce the role of cooling.

Setup: Varies; may include outdoor space, lab, or community setting

Materials: Experience setup materials, Reflection journal with prompts, Observation worksheet, Connection-to-content framework

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

Teaching This Topic

Teachers approach this topic by anchoring lessons in objects students can manipulate: water, ice, bags, and glasses. Avoid telling students the answers; instead, ask them to compare what they see in sun versus shade or with and without wind. Research shows that repeated observation of the same phenomenon, paired with talk, helps students revise ideas about invisible gases and where water goes.

What to Expect

Successful learning looks like students using the terms evaporation and condensation accurately, explaining where water goes on dry days and how droplets form on cold surfaces. They should describe heat and cooling as key causes, supported by evidence from their own tests and measurements.

Watch Out for These Misconceptions

Common Misconception

During Outdoor Hunt: Puddle Measurements, watch for students saying the water disappeared or was drunk by the sun.

What to Teach Instead

Use the puddle measurements and class data to show that the water is still present as vapour in the air; later, during Condensation Bags, students will see vapour reforming as droplets, revising their idea through direct observation.

Common Misconception

During Station Rotation: Evaporation Conditions, watch for students attributing evaporation to the sun 'sucking up' water.

What to Teach Instead

Have students compare drying times in sun versus shade and note the thermometer readings; the data will show that heat energy, not magical action, drives the change.

Common Misconception

During Whole Class Demo: Glass Mystery, watch for students thinking condensation only happens outside on windows or leaves.

What to Teach Instead

Use the glass demo to show condensation forming inside the classroom on a cold drink glass; ask students to list other cold surfaces they know to generalize the concept.

Assessment Ideas

Quick Check

After Whole Class Demo: Glass Mystery, show students a glass of ice water and ask, 'What do you see forming on the outside of the glass? Where did that water come from?' Record their answers to gauge understanding of condensation.

Exit Ticket

After Outdoor Hunt: Puddle Measurements, provide students with two scenarios: 'A puddle on a sunny, windy day' and 'A puddle on a cool, cloudy day'. Ask them to write one sentence explaining which puddle will disappear faster and why, using the terms evaporation and condensation.

Discussion Prompt

During Station Rotation: Evaporation Conditions, pose the question: 'Imagine you are a water droplet in a puddle. Describe what happens to you on a hot day and then what happens when the sun goes down.' Encourage students to use scientific vocabulary in their explanations.

Extensions & Scaffolding

• Challenge: Ask students to design a mini-experiment to test whether a wet paper towel evaporates faster in a closed bag or open air, then present their plan to the class.
• Scaffolding: Provide sentence stems like 'When the sun warms the puddle, the water changes to...' to support students who need help articulating the process.
• Deeper: Invite students to create a comic strip showing a water droplet’s journey through evaporation, condensation, and precipitation, labeling each stage with the cause and effect.

Key Vocabulary

Evaporation	The process where liquid water turns into a gas, called water vapor, usually when heated or exposed to wind.
Condensation	The process where water vapor in the air cools down and changes back into liquid water, forming droplets.
Water Vapor	Water in its gas form, which is invisible and mixes with the air.
Water Cycle	The continuous movement of water on, above, and below the surface of the Earth, including evaporation and condensation.