To do this lesson and understand half-life and rates of radioactive decay, students should understand ratios and the multiplication of fractions, and be somewhat comfortable with probability.Games with manipulative or computer simulations should help them in getting the idea of how a constant proportional rate of decay is consistent with declining measures that only gradually approach zero.Include your ideas about how its half-life of 28.8 years would be important.Suggest ways that government agencies, such as your state's department of health, might test for strontium-90.The first lesson, Isotopes of Pennies, introduces the idea of isotopes.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.If they haven't changed their answers, ask them to explain why.
Ask students to explain the terms in their own words.
At the end of the lab, give them the opportunity to revisit these questions and change or justify their answers.
Procedure: Give each student a copy of the laboratory procedure called Radioactive Decay: A Sweet Simulation of Half-life.
If you lived in a city where there had been a nuclear accident, you and your family might be exposed to strontium-90, which is the principal health hazard in radioactive fallout because it can easily get into the water supply or milk and then be ingested by people.
Write about how the strontium-90 might accumulate in your body (teeth and bones) and how it might affect you.