Use melting ice to teach students about radioactive decay. With a ring stand, set a funnel of ice over a graduated cylinder and students can construct a decay curve by plotting meltwater volume against time. The author suggests setting up the apparatus shortly before class starts, so that the students come in to find the ice already melting, and must work out when the ice was put in the funnel. As the ice melts, explain how the demonstration relates to radioactive decay rates, and how radioactive decay can be used to date various materials, breaking periodically to take new meltwater measurements.
An extension of the experiment is to spike one cylinder with saltwater concentration and to leave the beaker and information about its salt concentration beside the cylinder. This can serve as a demonstration of a contamination and the problems it presents for dating. The article also contains information about different kinds of funnels.
ISSN 1089-9995
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