Radiometric dating is used to estimate the age of rocks and other objects based on the fixed decay rate of radioactive isotopes.Learn about half-life and how it is used in different dating methods, such as uranium-lead dating and radiocarbon dating, in this video lesson. As we age, our hair turns gray, our skin wrinkles and our gait slows.So, if you know the radioactive isotope found in a substance and the isotope's half-life, you can calculate the age of the substance. Well, a simple explanation is that it is the time required for a quantity to fall to half of its starting value.So, you might say that the 'full-life' of a radioactive isotope ends when it has given off all of its radiation and reaches a point of being non-radioactive. This is an enormous branch of geochemistry called Geochronology. It is an accurate way to date specific geologic events.For example, a problem I have worked on involving the eruption of a volcano at what is now Naples, Italy, occurred 38500 years ago with a plus or minus of 300 years.
The best estimate from this dating technique says the man lived between 33 BC. From the ratio, the time since the formation of the rock can be calculated.
However, rocks and other objects in nature do not give off such obvious clues about how long they have been around.
So, we rely on radiometric dating to calculate their ages.
The technique of comparing the abundance ratio of a radioactive isotope to a reference isotope to determine the age of a material is called radioactive dating.
Many isotopes have been studied, probing a wide range of time scales.