A Simple Calorimetric Experiment That Highlights Aspects of Global Heat Retention and Global Warming
Joel D. Burley
Department of Chemistry, Saint Mary's College of California, Moraga, CA 94575-4527
Harold S. Johnston
Department of Chemistry, University of California and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
In this laboratory experiment, general chemistry students measure the heating curves for three different systems: (i) 500 g of room-temperature water heated by a small desk lamp, (ii) 500 g of an ice–water mixture warmed by conduction with room-temperature surroundings, and (iii) 500 g of an ice–water mixture heated by a small desk lamp and by conduction with room-temperature surroundings. The students verify that heat is consumed in the melting of ice, with no increase in temperature until all the ice has melted. The fundamental calorimetric principles demonstrated by the lab results are then directly connected to the topic of global warming, and a more precise terminology—one that distinguishes between global heat retention and global warming—is developed to help students better assess and understand the experimental evidence associated with global warming.
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Further descriptions of this experiment including quantitative, homework-style problems, the student laboratory handout, and alternative experimental configurations are available.
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