Radiometric dating--the process of determining the age of rocks from the decay of their radioactive elements--has been in widespread use for over half a century.
There are over forty such techniques, each using a different radioactive element or a different way of measuring them.
He was employed at Caltech's Division of Geological & Planetary Sciences at the time of writing the first edition.
He is presently employed in the Space & Atmospheric Sciences Group at the Los Alamos National Laboratory.
An element will undergo decay if: The concept of radioactive decay was first discovered in 1896 by Henri Becquerel as he was working the element uranium compounds.
In his first experiment, he placed the uranium on top of photographic film wrapped in dark paper and placed the crystals in the sunlight.
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.
The film darkened in response to some type of energy, which Bequerel assumed to be the prescence of the sun.
However, Becquerel's second experiment revealed something much more interesting.
The exercise they will go through of predicting and successively counting the number of remaining "mark-side up" candies should help them understand that 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 lesson can be done in two, 45-minute class periods.