Radiometric Dating: Methods, Uses & the Significance of Half-Life

Radiometric dating

Many rocks and organisms contain radioactive isotopes, such as Radioactive isotopes dating rocks and C These radioactive isotopes are unstable, decaying over time at a predictable rate. As the isotopes decay, they give off particles from their nucleus and become a different isotope. The parent isotope is the original unstable isotope, and daughter isotopes are the stable product of the decay.

Half-life is the amount of time it takes for half of the parent isotopes to decay. The decay occurs on a logarithmic scale. For example, the half-life of C is 5, years. In the first 5, years, the organism will lose half of its C isotope. In another 5, years, the organism will lose another half of the remaining C isotopes.

This process continues over time, with the organism losing half of the remaining C isotopes each 5, years. Fossils are collected along with rocks that occur from jsotopes same strata. These samples are carefully cataloged and analyzed with a mass spectrometer. The mass spectrometer is able to give information about the type and amount of isotopes found in the rock. Scientists find the ratio of parent isotope to daughter isotope. By comparing this ratio to the half-life logarithmic scale of the parent isotope, they are able to find the age of the rock or fossil in question.

There are several common radioactive isotoped that are used for dating rocks, artifacts and fossils. The most common is U U is found in many igneous rocks, soil and sediment. U decays to Pb with a half-life of million years. Due to its long half-life, U is the best isotope for radioactive dating, particularly of older fossils and rocks. C is another radioactive isotope that decays to C This isotope is found in all living organisms.

Once an organism dies, the C begins to decay. The half-life of C, however, is only 5, years. Because of its short half-life, the number of C isotopes in a sample is negligible after about 50, years, making it impossible to use for dating older samples. C is used often in dating artifacts from humans. Corina Fiore is a writer and photographer living in suburban Philadelphia. She earned a B.

Fiore taught high school science for 7 years and offered several teacher workshops to regarding education techniques. She worked as a staff writer for science texts and has been published in Praxis review materials for beginning teachers. Astronomy Biology Chemistry Electronics Energy Geology Math Nature Physics. By Corina Fiore; Updated April 24, Radioactive Decay Many rocks and organisms contain radioactive isotopes, such as U and C References Radioactive Dating Clocks in the Rocks Determining Radioacrive of Rocks and Fossils.

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