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Environment Climate change
Class 10 Beginner About 15 min Free

The greenhouse effect in a jar

Shine a lamp on an open jar, a covered jar and a covered jar of extra carbon dioxide, and compare how warm each gets.

Core concept

Greenhouse gases such as carbon dioxide let sunlight in but trap heat radiated from the ground, warming the Earth

Topic: Climate change

Sunlight passes through the air and warms the ground. The warm ground gives off heat as infrared radiation. Greenhouse gases in the air, such as carbon dioxide: A gas we breathe out. Plants take it in to make their food. All key words, methane and water vapour, absorb much of this infrared and send some of it back down, so the Earth stays warmer than it would otherwise be. This greenhouse effect is natural and keeps the Earth habitable, but burning fuels and cutting forests have raised the amount of carbon dioxide, trapping more heat and warming the climate. In this model a lamp is the Sun and a jar with dark soil is the Earth.

Key words explained

What you will learn

  • Compare the warming of jars with and without a cover and extra carbon dioxide.
  • Explain how greenhouse gases trap heat.
  • Link the model to global warming and its effects on Nepal.

Before you start

  • Know that heat can travel by radiation.

Materials

  • Dark soil, carbon dioxide (from vinegar and baking soda)

Equipment

  • Glass jars with lids, thermometers, desk lamp, stopwatch

Procedure

  1. Put an open jar under the lamp and record the temperature after 5, 10 and 20 minutes.
  2. Repeat with a lid on the jar, recording after 20 minutes.
  3. Repeat with a lid and extra carbon dioxide in the jar, recording after 20 minutes.

How this simulation is simplified

  • The room is at 20 °C. Under the lamp the jars warm towards 26 °C (open), 30 °C (lid) and 33 °C (lid with carbon dioxide), reaching most of the way in about 8 minutes.
Bench