Greenhouse Analogy with Chocolate

This classroom activity models the greenhouse effect using chocolate squares instead of thermometers. By comparing how quickly chocolate melts inside and outside a transparent container under a light source or the Sun, students observe how greenhouse gases trap heat in Earth’s atmosphere.

1. Begin with a discussion about why Earth is warmer than the Moon, even though both receive the same sunlight. Explain that Earth’s atmosphere, rich in greenhouse gases, traps heat.
2. Provide each group with a transparent container, chocolate squares, and a light source or direct sunlight.
3. Place one chocolate square inside the container and another outside as a control. Seal the container with plastic wrap or modeling clay if necessary.
4. Expose both setups to sunlight or a lamp.
5. Observe the chocolates at regular intervals, noting how quickly the one inside the container softens or melts compared to the control.
6. Discuss results as a class, linking the faster melting inside the container to the role of greenhouse gases in trapping heat.

Greenhouse effect - Experiment video: an analogy of the greenhouse effect - Office for Climate Education:

📄 THE GREENHOUSE EFFECT: UNDERSTANDING WITH AN ANALOGY - oce.global: https://www.oce.global/sites/default/files/2023-04/A2%20EN_0.pdf

• Use butter instead of chocolate as the heat-sensitive material.
• Compare results using glass versus plastic containers.
• Try the experiment outside in sunlight versus inside under a lamp.
• Test with different container sizes to see how the rate of melting changes.

• Handle lamps and hot bulbs carefully to avoid burns.
• Keep the container stable so melted chocolate does not spill.
• Do not eat the experimental chocolate.

• Why did the chocolate inside the container melt faster? (The container trapped heat, similar to how greenhouse gases trap infrared radiation in Earth’s atmosphere.)
• How does this model help explain why Earth is warmer than the Moon? (Earth has an atmosphere with greenhouse gases; the Moon does not.)
• Which gases act like the container in this analogy? (Carbon dioxide, methane, nitrous oxide, and water vapor.)
• What human activities increase greenhouse gas levels? (Energy production, transportation, agriculture, and industry.)