4) To demonstrate how the rate of radioactive decay and the buildup of the resulting decay product is used in radiometric dating of rocks. (A single watch or clock for the entire class will do.) 6) Piece of paper marked TIME and indicating either 2, 4, 6, 8, or 10 minutes.5) To use radiometric dating and the principles of determining relative age to show how ages of rocks and fossils can be narrowed even if they cannot be dated radiometrically. 2) Large cup or other container in which M & M's can be shaken. 7) 128 small cards or buttons that may be cut from cardboard or construction paper, preferably with a different color on opposite sides, each marked with "U-235" all on one colored side and "Pb-207" on the opposite side that has some contrasting color.On a piece of notebook paper, each piece should be placed with the printed M facing down. The candy should be poured into a container large enough for them to bounce around freely, it should be shaken thoroughly, then poured back onto the paper so that it is spread out instead of making a pile.This first time of shaking represents one half life, and all those pieces of candy that have the printed M facing up represent a change to the daughter isotope.Students should be able to understand the principles and have that as a background so that age determinations by paleontologists and geologists don't seem like black magic. Geologists in the late 18th and early 19th century studied rock layers and the fossils in them to determine relative age.
Return to top A tasty way for students to understand about half life is to give each team 100 pieces of "regular" M & M candy.
It is estimated to require four hours of class time, including approximately one hour total of occasional instruction and explanation from the teacher and two hours of group (team) and individual activities by the students, plus one hour of discussion among students within the working groups.
Explore this link for additional information on the topics covered in this lesson: This activity will help students to have a better understanding of the basic principles used to determine the age of rocks and fossils. Objectives of this activity are: 1) To have students determine relative age of a geologically complex area.
This happens at any time when addition of the fleeting "weak nuclear force" to the ever-present electrostatic repulsion exceeds the binding energy required to hold the nucleus together.
Very careful measurements in laboratories, made on VERY LARGE numbers of U-235 atoms, have shown that each of the atoms has a chance of decaying during about 704,000,000 years.