The greenhouse effect: understanding with an analogy

As part of The Climate in Our Hands – Ocean and Cryosphere, the activity “The Greenhouse Effect: Understanding with an Analogy” helps students explore how greenhouse gases contribute to global warming. By constructing a physical model of a greenhouse, learners investigate how heat is trapped inside a container—and how this mimics the way Earth's atmosphere retains heat through greenhouse gases.

What is this activity about?

In this lesson, students conduct a hands-on experiment to understand the greenhouse effect. By building a simple greenhouse using transparent materials and measuring temperature changes inside and outside the structure, they simulate the effect of greenhouse gases in the atmosphere. This activity encourages experimental thinking, data collection, and critical analysis, while reinforcing the physical basis of climate change.

Key Information

• Subjects: Natural sciences

• Duration: 1 hour 30 minutes (plus 10 minutes for preparation)

• Teaching method: Scientific experimentation and guided discussion

• Key learning outcomes

  • Understand the basic mechanism of the greenhouse effect

  • Learn how greenhouse gases trap infrared radiation

  • Connect experimental results to real-world climate processes

  • Differentiate between the greenhouse effect and other atmospheric phenomena (e.g. ozone depletion)

  • Develop skills in observation, measurement, and hypothesis testing

How does it work?

Preparation (10 min)

Gather and prepare the following for each group of 3–4 students:

• A transparent container (glass or thin plastic)

• 2 thermometers

• A light bulb (60–100W incandescent or halogen), or perform the activity in direct sunlight

• Optional: Modelling clay to seal the container

Introduction (20 min)

Begin by revisiting students’ prior knowledge about global warming. Ask them to brainstorm causes of temperature increase. Discuss concepts associated with the greenhouse effect and guide the class toward identifying greenhouse gases as a key factor.

Activity (50 min)

Step 1: Ask students how they might test the greenhouse effect. They will likely suggest building a greenhouse. Step 2: Each group constructs a mini-greenhouse. One thermometer goes inside the container; one remains outside. Step 3: Students take temperature readings at regular intervals and record the data in a table. Step 4: Discuss why the temperature increases. Introduce the idea that greenhouse gases in the atmosphere behave similarly to the greenhouse cover. Step 5: Use the analogy to explain how infrared radiation is trapped by greenhouse gases, causing warming. → If you do not continue to Lesson B3, provide and analyze Worksheet B3.4, which explores sources of greenhouse gases.

Wrap-up (20 min)

Reflect on the experiment and its implications:

• The atmosphere functions like a transparent blanket that retains heat

• Greenhouse gases (CO₂, methane, water vapor…) absorb infrared radiation and re-emit it toward the Earth's surface

• Without this natural effect, Earth’s average temperature would be around –18°C instead of 15°C → Emphasize the difference between the greenhouse effect and the ozone hole

Why use this activity in your classroom?

• Hands-on and visual: Makes an invisible phenomenon observable and measurable

• Engaging: Encourages teamwork, problem-solving, and scientific questioning

• Clarifies misconceptions: Differentiates between climate change and ozone depletion

• Foundational knowledge: Lays the groundwork for understanding the causes of global warming

• Scientific literacy: Introduces the electromagnetic spectrum and the concept of infrared radiation