Radioactive decay and fossil dating
For example, uranium-lead dating can be used to find the age of a uranium-containing mineral.
It works because we know the fixed radioactive decay rates of uranium-238, which decays to lead-206, and for uranium-235, which decays to lead-207.
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Carbon-14 is continually being created in the atmosphere due to the action of cosmic rays on nitrogen in the air.
Carbon-14 combines with oxygen to create carbon dioxide.
For example, how do we know that the Iceman, whose frozen body was chipped out of glacial ice in 1991, is 5,300 years old?
Well, we know this because samples of his bones and hair and even his grass boots and leather belongings were subjected to radiocarbon dating.
The thing that makes this decay process so valuable for determining the age of an object is that each radioactive isotope decays at its own fixed rate, which is expressed in terms of its half-life.Radiometric dating, or radioactive dating as it is sometimes called, is a method used to date rocks and other objects based on the known decay rate of radioactive isotopes.Different methods of radiometric dating can be used to estimate the age of a variety of natural and even man-made materials.So, we start out with two isotopes of uranium that are unstable and radioactive.They release radiation until they eventually become stable isotopes of lead.