Since the rate at which this conversion occurs is known, it is possible to determine the elapsed time since the mineral formed by measuring the ratio of U, as the source of radiogenic heat.
The core also likely contains radiogenic sources, although how much is uncertain.
About 89.28% of the time, it decays to calcium-40 ( Potassium-40 is especially important in potassium–argon (K–Ar) dating.
Argon is a gas that does not ordinarily combine with other elements.
The calcium-potassium age method is seldom used, however, because of the great abundance of nonradiogenic calcium in minerals or rocks, which masks the presence of radiogenic calcium.
However, if the mineral contains any potassium, then decay of the K isotope present will create fresh argon-40 that will remain locked up in the mineral.If we knew the fraction of a radioactive element still remaining in a mineral, it would be a simple matter to calculate its age by the formula To determine the fraction still remaining, we must know both the amount now present and also the amount present when the mineral was formed.Contrary to creationist claims, it is possible to make that determination, as the following will explain: By way of background, all atoms of a given element have the same number of protons in the nucleus; however, the number of neutrons in the nucleus can vary.It has the same number of protons, otherwise it wouldn't be uranium.The number of protons in the nucleus of an atom is called its atomic number.