Science · Year 5 · Properties and Changes of Materials · Autumn Term

Evaporation and Condensation

Exploring how liquids turn into gases (evaporation) and gases turn back into liquids (condensation), linking to the water cycle.

• National Curriculum Attainment Targets
• NC-KS2-Science-Y5-PCM-3

About This Topic

Evaporation occurs when liquid particles gain enough energy to escape into the air as a gas, happening at any temperature below boiling point. Condensation is the reverse process, where gas particles lose energy and form liquid droplets upon cooling. These changes of state are central to the water cycle, as water evaporates from seas and rivers, rises, cools in the atmosphere, condenses into clouds, and falls as precipitation.

This topic fits within the Properties and Changes of Materials unit, helping Year 5 students observe how temperature, surface area, and airflow affect evaporation rates. They compare evaporation, which is gradual, to boiling, a rapid change at 100°C driven by continuous heating. Predicting condensation in situations like cold drink glasses or bathroom mirrors builds explanatory skills and links to everyday observations.

Active learning suits this topic well. Simple experiments, such as comparing water loss from dishes in sun, shade, wind, or still air, let students measure and graph changes directly. These hands-on tasks reveal patterns through data collection and discussion, turning abstract particle ideas into concrete evidence students can debate and refine.

Key Questions

1. Explain how evaporation is different from boiling.
2. Compare the processes of evaporation and condensation.
3. Predict where condensation might form in everyday situations and justify why.

Learning Objectives

• Compare the processes of evaporation and condensation, identifying key differences in energy requirements and outcomes.
• Explain how temperature, surface area, and airflow influence the rate of evaporation.
• Predict where condensation is likely to form in everyday scenarios, such as on a cold glass or a bathroom mirror, and justify the prediction based on cooling.
• Illustrate the role of evaporation and condensation in the water cycle using a labeled diagram.

Before You Start

States of Matter

Why: Students need to know that water exists as a solid, liquid, and gas to understand how it changes between these states.

Temperature and Heat

Why: Understanding that heat provides energy is crucial for explaining why liquids evaporate and gases condense.

Key Vocabulary

Evaporation	The process where a liquid changes into a gas or vapor, typically when heated. This happens at temperatures below boiling point.
Condensation	The process where a gas or vapor changes into a liquid. This occurs when the gas cools down and loses energy.
Water Cycle	The continuous movement of water on, above, and below the surface of the Earth, involving evaporation, condensation, precipitation, and collection.
Boiling Point	The specific temperature at which a liquid turns into a gas when heated continuously. For water, this is 100°C.

Watch Out for These Misconceptions

Common Misconception

Evaporation only happens at boiling point.

What to Teach Instead

Evaporation occurs slowly at room temperature as surface particles escape; boiling requires 100°C for all particles. Hands-on dish experiments show gradual water loss without heat, prompting students to revise ideas through measurement and peer comparison.

Common Misconception

Condensation needs a fridge or very cold temperatures.

What to Teach Instead

Condensation forms whenever gas cools below dew point, like on cold glasses. Window breath demos let students see it instantly, discuss air moisture, and connect to real observations, correcting over-reliance on extreme examples.

Common Misconception

Evaporated water disappears forever.

What to Teach Instead

Water vapour remains in air until condensing elsewhere. Tracking classroom humidity or jar cycles shows conservation, with group discussions reinforcing matter cycles over loss.

Active Learning Ideas

Investigation Stations: Evaporation Rates

Prepare stations with identical water volumes in dishes under different conditions: sunlight, shade, fan, and covered. Students measure and record water levels every 10 minutes, then graph results and discuss factors affecting speed. Conclude by predicting fastest evaporation.

45 min·Small Groups

Demo Pair: Condensation Jar

Pairs fill clear jars with hot water, cover with plastic wrap and ice cubes. They observe droplets forming on the wrap, wipe and time re-formation, then explain using particle theory. Extend by testing cold mirror with breath.

20 min·Pairs

Prediction Walk: Classroom Hunt

Students walk the room or school, noting spots where condensation forms like windows or pipes. In pairs, they predict causes, justify with temperature differences, and share findings in whole class vote on best examples.

30 min·Pairs

Whole Class: Evap vs Boil Timeline

Project images of evaporating puddle and boiling kettle. Class brainstorms timelines of particle movement, then acts out in role-play: slow drift for evaporation, rapid bubble for boiling. Vote on key differences.

25 min·Whole Class

Real-World Connections

• Meteorologists use their understanding of evaporation and condensation to forecast weather patterns, predicting cloud formation and precipitation events for regions across the United Kingdom.
• Brewers and distillers carefully control temperature and airflow in their facilities to manage evaporation rates during the production of beverages like beer and spirits, ensuring product quality.
• Clothing manufacturers design fabrics that wick moisture away from the skin, utilizing principles of evaporation to keep wearers dry and comfortable during physical activity.

Assessment Ideas

Exit Ticket

Provide students with two scenarios: 1) A puddle drying up on a sunny day. 2) Water droplets forming on the outside of a cold juice bottle. Ask students to write one sentence for each scenario explaining whether evaporation or condensation is occurring and why.

Quick Check

During a lesson segment on factors affecting evaporation, ask students to hold up fingers to indicate the relative effect of increasing surface area (1=little effect, 5=large effect). Then, ask them to do the same for increasing airflow. Discuss their responses.

Discussion Prompt

Pose the question: 'Imagine you are designing a system to dry clothes quickly. What two factors related to evaporation would you try to maximize, and why?' Facilitate a class discussion where students justify their choices based on scientific principles.

Frequently Asked Questions

How do you explain evaporation versus boiling to Year 5?

Evaporation is a surface process at any temperature, like wet clothes drying, while boiling happens throughout the liquid at 100°C with bubbles. Use timelines: slow particle escape for evaporation, fast vibration and bursting for boiling. Dishes in varying conditions provide evidence students measure themselves.

What everyday examples illustrate condensation?

Cold drink cans sweating on hot days, bathroom mirrors fogging after showers, or car windows misting in mornings. Students predict and observe these, linking to air holding less moisture when cooled. This builds justification skills through familiar contexts.

How can active learning help teach evaporation and condensation?

Activities like evaporation trays under fans or condensation jars with ice engage students kinesthetically. They collect data, graph rates, and debate patterns in groups, making particle movement observable. This shifts from rote recall to evidence-based understanding, boosting retention and skills like prediction.

How does this topic link to the water cycle?

Evaporation lifts water vapour from surfaces into air; condensation forms clouds as it cools. Students model with bags or terrariums, tracing paths. This connects states of matter to larger systems, preparing for weather units with practical cycle diagrams.