Exploring Exponential Decay Using Limited Resources

Abstract

Science students need exposure to activities that will help them to become familiar with phenomena exhibiting exponential decay. This paper describes an experiment that allows students to determine the rate of thermal energy loss by a hot object to its surroundings. It requires limited equipment, is safe, and gives reasonable results. Students record the decreasing temperature values displayed by a thermometer, which was initially heated by body contact. The procedure is easy to repeat, taking only 3 min. The students then convert temperature changes into thermal energy losses and plot graphs. Data analysis can be used to teach graphing and ratio interpretation. This experiment can be used by high school or first-year college students in situations where resources or space may be limited or where large student populations dictate a need for uncomplicated experimental procedures, particularly those that minimize the production of chemical waste.