Benchtop Global-Warming Demonstrations Do Not Exemplify the Atmospheric Greenhouse Effect, but Alternatives Are Available

摘要

The atmospheric greenhouse effect is a topic in many science courses. A number of lecture demonstrations with carbon dioxide purport to show how infrared-absorbing atmospheric gases "trap" energy. The demonstration described here shows that the temperature change observed in these demonstrations is a consequence of the density of carbon dioxide relative to air, not its infrared-absorbing property. Since the pedagogical value instructors report for the usual demonstration is based on an incorrect interpretation of the temperature change and can lead to a misconception about global warming, suggestions are made for possible replacement demonstrations.