Symbolically, the process of radioactive decay can be expressed by the following differential equation, where N is the quantity of decaying nuclei and k is a positive number called the exponential decay constant.

The meaning of this equation is that the rate of change of the number of nuclei over time is proportional only to the number of nuclei.

The example used here contrasts sharply with the way conventional scientific dating methods are characterized by some critics (for example, refer to discussion in "Common Creationist Criticisms of Mainstream Dating Methods" in the Age of the Earth FAQ and Isochron Dating FAQ).

A common form of criticism is to cite geologically complicated situations where the application of radiometric dating is very challenging.

The key is to measure an isotope that has had time to decay a measurable amount, but not so much as to only leave a trace remaining.

Given isotopes are useful for dating over a range from a fraction of their half life to about four or five times their half life.

his document discusses the way radiometric dating and stratigraphic principles are used to establish the conventional geological time scale.

When an isotope decays, it often becomes a different kind of element altogether.But there are some questions that come to mind: Calculus students typically meet this problem somewhere in the second semester.It is one of the simplest examples of a differential equation.Imagine we have an undiscovered element, Parentium, that has a radioactive isotope, Parentium-123, which decays to stable Daughterium-123.This is the only way Parentium-123 decays, and there is no other source of Daughterium-123.