Radiometric dating or radioactive dating is any technique used to date organic and also inorganic materials from a process involving radioactive decay. The method compares the abundance of a naturally occurring radioactive isotope within the material to the abundance of its decay products, which form at a known constant rate of decay. All these methods are based on the fact the rate at which radioactive nuclei disintegrate is unaffected by their environment, it can be used to estimate the age of any material sample or object which contains a radioactive isotope. Calculations of the decay of radioactive nuclei are relatively straightforward, owing to the fact that there is only one fundamental law governing all decay process. The radioactive decay law states that the probability per unit time that a nucleus will decay is a constant, independent of time. This constant probability may vary greatly between different types of nuclei, leading to the many different observed decay rates.
What Is Half-Life?
What Half Life Means for Evolution
Uranium 92 U is a naturally occurring radioactive element that has no stable isotope. It has two primordial isotopes , uranium and uranium , that have long half-lives and are found in appreciable quantity in the Earth's crust. The decay product uranium is also found. Other isotopes such as uranium have been produced in breeder reactors.
Carbon has a large number of stable isotopes. All carbon atoms contain six protons and six electrons, but the different isotopes have different numbers of neutrons. The amount of carbon in the atmosphere has not changed in thousands of years.
Perhaps the most widely used evidence for the theory of evolution through natural selection is the fossil record. The fossil record may be incomplete and may never fully completed, but there are still many clues to evolution and how it happens within the fossil record. One way that helps scientists place fossils into the correct era on the geologic time scale is by using radiometric dating. Also called absolute dating, scientists use the decay of radioactive elements within the fossils or the rocks around the fossils to determine the age of the organism that was preserved. This technique relies on the property of half-life.