2) To familiarize students with the concept of half-life in radioactive decay.
3) To have students see that individual runs of statistical processes are less predictable than the average of many runs (or that runs with relatively small numbers involved are less dependable than runs with many numbers).
The teacher should tell the students that there are two basic principles used by geologists to determine the sequence of ages of rocks.
Radioactive dating shows that
Principle of cross-cutting relations: Any geologic feature is younger than anything else that it cuts across.
Some elements have forms (called isotopes) with unstable atomic nuclei that have a tendency to change, or decay.
Return to top Each team of 3 to 5 students should discuss together how to determine the relative age of each of the rock units in the block diagram (Figure 1).
After students have decided how to establish the relative age of each rock unit, they should list them under the block, from most recent at the top of the list to oldest at the bottom.
Students not only want to know how old a fossil is, but they want to know how that age was determined.