Living things have about 15 disintegrations per minute per gram of carbon.
This lesson is the third in a three-part series about the nucleus, isotopes, and radioactive decay.The first lesson, Isotopes of Pennies, deals with isotopes and atomic mass.The second lesson, Radioactive Decay: A Sweet Simulation of Half-life, introduces the idea of half-life.By the end of the 8th grade, students should know that all matter is made up of atoms, which are far too small to see directly through a microscope.However, the carbon-14 that was in the organism at death continues to disintegrate.
By measuring how much carbon is left in a sample as well as its radioactivity, we can calculate when the organism died. In this activity, you will work backwards to solve a puzzle, much like scientists work backwards to find the time that an organism died." Procedure Give each student a copy of The Case of the Melting Ice student sheet.(This page has been archived and is found on the Internet Archive.) In addition to using answers to students' Analysis questions and their graphs for evaluation, consider having them respond to the following in their science journals or as a homework essay: Pretend you are on a month-long field trip to dig for artifacts that might have been left from the pre-colonial period in the United States.Write a letter to a friend explaining what radiocarbon dating is.You can refer to How Carbon-14 Dating Works, from How Stuff Works, to help you answer the question.This activity was selected for the On the Cutting Edge Reviewed Teaching Collection This activity has received positive reviews in a peer review process involving five review categories.Students should complete the Analysis section of the lab sheet, which will be used as part of their assessment.