Using Melting Ice to Teach Radiometric Dating

• Explore ice melting as an analogue to radiometric decay.

This activity is appropriate for use in an introductory geology course as a means to discuss the issues of radiometric dating and geologic time.

• Funnel and Ring Stand
• Medium sized graduated cylinder
• Chopped/Cubed Ice
• Graph Paper for plotting the melting curve

The author's original article has suggestions for a storyline to go along with the activity.

• Large, thin-walled metal funnels are best because of their high thermal conductivity.
• Don't allow too much time between taking the ice out of the freezer and putting it into the apparatus. Some supercooling is desirable.
• Use a large vertical scale on the graphs to produce a steep slope and enable students to easily project the line back to time-zero.
• Start the activity before class begins so that students don't have to deal with the thermal disequilibrium issues at the outset.
• The first couple of data point can be supplied to shorten the activity.

When students have finished plotting their data, they should check their answer for time-zero against the answer provided by the instructor. Student participation is the aim of this exercise.

Quantiative Skills Addressed

Geoscience Topics Covered