Changes of State: Evaporation and Condensation

Active learning works well for this topic because evaporation and condensation happen all around us, but students often miss the science behind everyday events. By measuring, observing, and designing, students connect particle behavior to real phenomena they see in their lives.

• Year 5
• Science
• 4 activities
• 25 min–50 min

Learning Objectives

1. Analyze the effect of temperature, surface area, and airflow on the rate of evaporation.
2. Explain the process of condensation and its role in cloud formation.
3. Design a controlled experiment to investigate factors affecting evaporation.
4. Compare and contrast evaporation and condensation as reversible changes of state.

Inquiry Circle

⏱ 45 min·Small Groups

Investigation Stations: Evaporation Factors

Prepare stations for temperature (hot vs room temp water), surface area (wide vs narrow dishes), airflow (with fan vs still air), and humidity (covered vs open). Students predict outcomes, measure mass loss every 5 minutes for 20 minutes, record data, then rotate. Conclude with class graph discussion.

Prepare & details

Analyze the factors that increase the rate of evaporation.

Facilitation Tip: During Investigation Stations: Evaporation Factors, place the containers in different locations at the same time to minimize variables like air movement or sunlight changes.

Setup: Groups at tables with access to source materials

Materials: Source material collection, Inquiry cycle worksheet, Question generation protocol, Findings presentation template

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

Inquiry Circle

⏱ 25 min·Pairs

Cloud in a Jar: Condensation Demo

Half-fill clear jars with hot water, seal with plastic wrap, and place ice cubes on top. Students observe water droplets forming on the plastic underside and sketch changes. Guide discussion on cooling vapor and cloud formation parallels. Pairs then try variations like adding smoke for visible particles.

Prepare & details

Explain how condensation leads to cloud formation.

Facilitation Tip: When running Cloud in a Jar: Condensation Demo, use warm water and ice to create a clear temperature gradient, making the condensation layer visible.

Setup: Groups at tables with access to source materials

Materials: Source material collection, Inquiry cycle worksheet, Question generation protocol, Findings presentation template

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

Inquiry Circle

⏱ 50 min·Pairs

Design Challenge: Evaporation Experiment

Pairs brainstorm a fair test for one evaporation factor, write hypotheses and procedures, gain approval, then conduct trials measuring drying time or mass change. They present results with graphs to the class. Emphasize safety and variables control.

Prepare & details

Design an experiment to demonstrate the process of evaporation.

Facilitation Tip: In Design Challenge: Evaporation Experiment, require students to measure mass changes over time using the same balance for all containers to ensure reliable data.

Setup: Groups at tables with access to source materials

Materials: Source material collection, Inquiry cycle worksheet, Question generation protocol, Findings presentation template

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

Inquiry Circle

⏱ 30 min·Small Groups

Classroom Hunt: Real-Life Examples

Provide checklists of evaporation and condensation signs around school (wet clothesline, cold drink condensation). Students in small groups photograph or sketch examples, explain processes using particle ideas, and share in a gallery walk.

Prepare & details

Analyze the factors that increase the rate of evaporation.

Facilitation Tip: During Classroom Hunt: Real-Life Examples, have students take photos of their examples and explain the process in writing to reinforce observation and reasoning.

Setup: Groups at tables with access to source materials

Materials: Source material collection, Inquiry cycle worksheet, Question generation protocol, Findings presentation template

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

Teaching This Topic

Teach this topic with a mix of hands-on experiments and guided questioning. Start with observations to build curiosity, then move to structured investigations to test variables. Avoid explaining particle theory too early; let evidence guide their understanding first. Research shows students grasp changes of state better when they connect particle behavior to measurable outcomes, so emphasize data collection and graphing throughout.

What to Expect

Students will accurately explain how temperature, surface area, and airflow affect evaporation, and how cooling leads to condensation. They will use evidence from experiments to revise misconceptions and apply their understanding to new situations.

Watch Out for These Misconceptions

Common Misconception

During Investigation Stations: Evaporation Factors, watch for students who assume evaporation only happens at high temperatures because they see boiling in daily life.

What to Teach Instead

During Investigation Stations: Evaporation Factors, have students graph the mass loss over time for each container. Ask them to connect the gradual decrease in mass (without bubbles) to the idea that evaporation occurs at all temperatures, even when no boiling is visible.

Common Misconception

During Cloud in a Jar: Condensation Demo, watch for students who think condensation only forms on solid surfaces like glass or mirrors.

What to Teach Instead

During Cloud in a Jar: Condensation Demo, ask students to observe the cloud forming in the air inside the jar. Then, have them draw the particle movement from warm vapor cooling to liquid droplets, emphasizing that surfaces just make condensation visible.

Common Misconception

During Design Challenge: Evaporation Experiment, watch for students who claim the water has disappeared entirely after evaporation.

What to Teach Instead

During Design Challenge: Evaporation Experiment, have students weigh the containers before and after evaporation. Then, during the condensation activity, ask them to predict where the “missing” water went, using their data to reinforce the idea of conservation of mass.

Assessment Ideas

Quick Check

After Investigation Stations: Evaporation Factors, present students with three identical containers of water placed in a sunny spot, a breezy area, and a cool, shaded spot. Ask them to predict which will evaporate fastest and explain why using the terms evaporation and kinetic energy.

Discussion Prompt

After Cloud in a Jar: Condensation Demo, ask students to imagine they are scientists studying clouds. Have them design an experiment to show how condensation forms clouds, guiding them to discuss variables like cooling and water vapor.

Exit Ticket

During Classroom Hunt: Real-Life Examples, ask students to draw a simple diagram illustrating evaporation and condensation. They should label the processes and write one sentence explaining the difference between them.

Extensions & Scaffolding

• Challenge: Ask students to design an experiment to test how humidity affects evaporation rate, then compare their results to published data.
• Scaffolding: Provide pre-labeled diagrams for students to fill in during the Cloud in a Jar activity, helping them link the demo to particle behavior.
• Deeper exploration: Introduce the concept of latent heat by measuring how the temperature of the container changes during evaporation and condensation.

Key Vocabulary

Evaporation	The process where a liquid changes into a gas or vapor, typically occurring at the surface of the liquid.
Condensation	The process where a gas or vapor changes into a liquid, often seen when water vapor cools.
Water Vapor	Water in its gaseous state, invisible in the air.
Kinetic Energy	The energy an object possesses due to its motion; in this context, the energy of particles within a substance.