Carbon dating lab activity
To demonstrate that the rates of decay of unstable nuclei can be measured, that the exact time that a certain nucleus will decay cannot be predicted, and that it takes a very large number of nuclei to find the rate of decay.This is the second lesson in a three-lesson series about isotopes, radioactive decay, and the nucleus.We know that radioactive substances disintegrate at a known rate, however. It is the length of time required for the disintegration of one-half of a given number of nuclei of a radioactive element. Suppose we have 100 nuclei of a radioactive isotope.After one half-life, half of the nuclei will have disintegrated, leaving 50 nuclei." Have students write their answers to these questions in their science journals.
The final lesson, Frosty the Snowman Meets His Demise: An Analogy to Carbon Dating, is based on gathering evidence in the present and extrapolating it to the past.To help students understand the history of radioactivity, have them go to Radioactivity: Historical Figures, on the Access Excellence Classic Collection site, to read about the contributions of Wilhelm Roentgen, Antoine Becquerel, Marie and Pierre Curie, and Ernest Rutherford.As students read about these scientists, ask them to think about the following questions: Students can supplement this site with a visit to Isotopes Project.It may be combined with the Frosty the Snowman Meets His Demise: An Analogy to Carbon Dating, which can be done while students are flipping their candies.In your planning, be sure to include time at the end of the lesson for students to post their data and share the class data.