Greenhouse Analogy with Chocolate
Materials: ★☆☆ Easy to get from supermarket or hardware store
Difficulty: ★☆☆ Can be easily done by most teenagers
Safety: ★☆☆ Minimal safety procedures required
Categories: Global Systems, The Atmosphere, Weather and Climate
Alternative titles: Melting Chocolate Greenhouse Model
Summary
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.
Procedure
- 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.
- Provide each group with a transparent container, chocolate squares, and a light source or direct sunlight.
- Place one chocolate square inside the container and another outside as a control. Seal the container with plastic wrap or modeling clay if necessary.
- Expose both setups to sunlight or a lamp.
- Observe the chocolates at regular intervals, noting how quickly the one inside the container softens or melts compared to the control.
- Discuss results as a class, linking the faster melting inside the container to the role of greenhouse gases in trapping heat.
Links
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
Variations
- 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.
Safety Precautions
- 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.
Questions to Consider
- 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.)