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Grade 10 Beginner About 15 min Version 1 Awaiting review Premium

The greenhouse effect in a jar

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, 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.

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.