Radioactive dating game answers
Suppose we have a tank partly filled with water, and a hole in the bottom through which the water is leaking out of the tank.
We wonder how long the hole has been there, that is, how old the hole is.
Modern methods can detect essentially any Carbon-14, and therefore produce dates up to about 100,000 years.
Usually, different amounts of lead will have been lost, for example more from the surface of the crystal than from the interior, so there will be a range of isotope ratios.