Mankind has made some incredible scientific discoveries and radioactive dating is one of them. Also called radiometric dating, this technique is used by geologists and physicists to determine how old a substance is. We have learned some fascinating history from dating rocks and fossils, thanks to dating. Radioactive dating has an important function, history and many interesting features. There are two main types, both of which have their limitations.
Function
Radioactive dating is used to date materials like rocks, fossils and other archaeological artifacts. This technique is important to use when artifacts are found because it's the main way that we establish our geological time scale. This dating helps us put together the Earth's history, long before our time. It helps us date buildings, figure out when extinct animals lived and even tells us how old the Earth is.
Features
Radioactive dating works by using the features of radioactive isotopes in rocks and their decaying products. Isotopes differ by the number of neutrons in their atomic nuclei and some are useful for dating. The chemical element that's used in radiometric dating is the nuclide, a type of isotope, because some of these are unstable and transform spontaneously. When these nuclides transform, some of the atoms decay at an exponential rate, which can be calculated and is called half-life.
Types
There are two main types of radioactive dating, based on how old the substance is that scientists are dating. The first is long-term dating, which can be used to date rocks that are over one billion years old. Specific kinds include using the half life of uranium, potassium, rubidium and strontium. The other type is short-range dating for younger artifacts. Carbon-14 is the main method here, with a much shorter half life of almost 6000 years.
History
Humans have been trying to date materials for centuries, possibly even before the 1700s. In the 1900s, scientists discovered that there were radioactive atoms inside rocks that break down and can help us date those rocks. The technique used to date samples much smaller than a gram is the mass spectrometer, invented in the 1940s and used first in the 1950s. This uses ionized atoms and magnetic fields to develop a current and determine the concentration of different atoms. Since then, scientists have discovered that many elements can help us determine the age of rocks.
Considerations
Radioactive dating is a complicated procedure and it's easy to create inaccurate results. Precision is of the utmost importance, and if the scientist doesn't take into consideration the contamination of parent and daughter isotopes and keep in mind the time that's passed since the sample was created, the results won't be precise enough. There are also limitations of each isotope's half-life--some are longer than others. And precision can be compromised if the rock isn't large enough to run two samples from different locations to help confirm age.
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