Radioactive decay[ edit ] Example of a radioactive decay chain from lead Pb to lead Pb. The final decay product, lead Pb , is stable and can no longer undergo spontaneous radioactive decay. All ordinary matter is made up of combinations of chemical elements , each with its own atomic number , indicating the number of protons in the atomic nucleus. Additionally, elements may exist in different isotopes , with each isotope of an element differing in the number of neutrons in the nucleus. A particular isotope of a particular element is called a nuclide. Some nuclides are inherently unstable.
Common Types of Radiometric Dating Carbon 14 Dating As shown in the diagram above, the radioactive isotope carbon originates in the Earth's atmosphere, is distributed among the living organisms on the surface, and ceases to replenish itself within an organism after that organism is dead. This means that lifeless organic matter is effectively a closed system, since no carbon enters the organism after death, an occurrence that would affect accurate measurements. In radiometric dating, the decaying matter is called the parent isotope and the stable outcome of the decay is called the daughter product. Since the half-life of carbon is years, scientists can measure the age of a sample by determining how many times its original carbon amount has been cut in half since the death of the organism. In all radiometric procedures there is a specific age range for when a technique can be used. If there is too much daughter product in this case nitrogen , age is hard to determine since the half-life does not make up a significant percentage of the material's age. The range of practical use for carbon dating is roughly a few hundred years to fifty thousand years.
Radiometric Dating: Methods, Uses & the Significance of Half-Life
Gillaspy has taught health science at University of Phoenix and Ashford University and has a degree from Palmer College of Chiropractic. 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. Radiometric Dating The aging process in human beings is easy to see.
Key implausible assumptions There are a number of implausible assumptions involved in radiometric dating with respect to long time periods. Initial quantities One key assumption is that the initial quantity of the parent element can be determined. With uranium-lead dating, for example, the process assumes the original proportion of uranium in the sample.