Activity 5: Effects of greenhouse gases

Dr. Cecilia Scorza and Moritz Strähle
Status: Mar 2023

With this central activity in the climate case, it is shown experimentally in two different ways that CO2 absorbs thermal radiation and the back radiation of the atmosphere is made vivid with a thermal imaging camera.

  1. Part: CO2 absorbs radiant energy (absorption measurement)
  2. Part: Infrared radiation is intercepted (transmission measurement).
  3. Part: Why does an absorption of infrared radiation in the atmosphere lead to a heating of the
    earth surface? (Back radiation of the atmosphere)


h5p-study unit for the activity:

More materials like h5p-study units, videos and animations with Module - The Greenhouse effect and the radiative Equilibrium.

    Video: The effect of greenhouse gases

    Technical questions and didactic comments

      Do you have a technical question about the experiment? Get in touch with us! We will gladly try to answer your question or forward it to an expert in our network. Answers to central or frequently asked questions will be published here.

      • Depending on the ambient temperature, the radiator takes approx. 25 minutes to warm up. It may therefore be advisable to switch it on before the start of the hour.
      • For the transmission measurement by thermal imaging camera a thermal imaging camera is necessary, where the temperature measuring range can be adjusted manually (e.g. FLIR C3X). To get a nice before and after comparison, a few settings are necessary, which are shown exemplarily with the FLIR C3X in the video of the experiment. It is recommended to vary the temperature range used, as the optimal setting also depends on the ceramic emitter used.
      • Instead of a thermal imaging camera, an inexpensive IR thermometer can also be used for the transmission measurement. After CO2 has been added, the indicated temperature drops because less heat radiation reaches the IR thermometer.
        Important: The IR thermometer must be fixed by means of a stand, since the temperature on the surface of the ceramic radiator is not uniform and movement of the thermometer leads to measurement errors.
      • Hazard assessment

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