6 rules relative age dating
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.
This activity on determining age of rocks and fossils is intended for 8th or 9th grade students.This is a stable condition, and there are no more changes in the atomic nucleus.A nucleus with that number of protons is called lead (chemical symbol Pb). This particular form (isotope) of lead is called Pb-207.U-235 is the parent isotope of Pb-207, which is the daughter isotope.Many rocks contain small amounts of unstable isotopes and the daughter isotopes into which they decay.In general, with the exception of the single proton that constitutes the nucleus of the most abundant isotope of hydrogen, the number of neutrons must at least equal the number of protons in an atomic nucleus, because electrostatic repulsion prohibits denser packing of protons.
But if there are too many neutrons, the nucleus is potentially unstable and decay may be triggered.
If the nucleus has not yet decayed, there is always that same, slight chance that it will change in the near future.
Atomic nuclei are held together by an attraction between the large nuclear particles (protons and neutrons) that is known as the "strong nuclear force", which must exceed the electrostatic repulsion between the protons within the nucleus.
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).
Where the amounts of parent and daughter isotopes can be accurately measured, the ratio can be used to determine how old the rock is, as shown in the following activities.