Radioactive age dating equation
The decay may happen by emission of particles (usually electrons (beta decay), positrons or alpha particles) or by spontaneous nuclear fission, and electron capture.
Plotting an isochron (straight-line graph) is used to solve the age equation graphically.
These tests which were mainly performed in the early 1960s, led to an increase of tritium in precipitation over the continents of the northern hemisphere from roughly 5 TU to levels of the order of 1000 TU.
One TU (Tritium Unit) means a tritium to hydrogen ratio of 10.
Fossils may be dated by taking samples of rocks from above and below the fossil's original position.
Radiometric dating (often called radioactive dating) is a way to find out how old something is.
As radioactive Parent atoms decay to stable daughter atoms (as uranium decays to lead) each disintegration results in one more atom of the daughter than was initially present and one less atom of the parent.
The probability of a parent atom decaying in a fixed period of time is always the same for all atoms of that type regardless of temperature, pressure, or chemical conditions. The time required for one-half of any original number of parent atoms to decay is the half-life, which is related to the decay constant by a simple mathematical formula.
Radioactivity was discovered in 1896 by French physicist Henri Becquerel.
By 1907 study of the decay products of uranium (lead and intermediate radioactive elements that decay to lead) demonstrated to B. Boltwood that the lead/uranium ratio in uranium minerals increased with geologic age and might provide a geological dating tool.