The time necessary for half of any given amount of one element (the “parent element”) to decay to become another element (the “daughter element”) is called the element’s “half-life.” Ice cores, for example, contain data about Earth’s past climate.
Geologists use a dating technique called K-Ar geochronology to find the age of layers of volcanic ash in ice cores. By measuring the ratio of K to Ar in feldspar crystals in volcanic ash, geologists can determine the time of the eruption and, thus, the age of ice in which the ash is found. Heating causes the kernels to begin popping, thereby starting your simulated “radioactive decay clock” and producing popped “daughter” popcorns.
Once they determine the age of a volcanic ash layer, geologists can study the materials in that ice core layer for clues about climate conditions at that time. The half-life of your kernel-popcorn material is the time necessary for half of the given kernels to become popcorns.
Radiometric dating or radioactive dating is a technique used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed.
To better understand how radiometric dating helps us determine the age of rocks, it will help us to gain a better understanding of how elements decay.
Radioactive decay is the term used for the process by which an unstable atomic nucleus loses energy by releasing radiation.
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).
Together with stratigraphic principles, radiometric dating methods are used in geochronology to establish the geological time scale.
Among the best-known techniques are radiocarbon dating, potassium-argon dating and uranium-lead dating.
The latest high-tech equipment permits reliable results to be obtained even with microscopic samples.
Radiometric dating is self-checking, because the data (after certain preliminary calculations are made) are fitted to a straight line (an "isochron") by means of standard linear regression methods of statistics.