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However, when the organism dies, the amount of c14 declines such that the longer the time since death the lower the levels of c14 in organic tissue.date of organic material - but an approximate age, usually within a range of a few years either way.Because carbon-14 decays at this constant rate, an estimate of the date at which an organism died can be made by measuring the amount of its residual radiocarbon.­ ­You probably have seen or read news stories about fascinating ancient artifacts.Once the organism dies, however, it ceases to absorb carbon-14, so that the amount of the radiocarbon in its tissues steadily decreases.Carbon-14 has a half-life of 5,730 ± 40 years— during the succeeding 5,730 years.Today, the radiocarbon-14 dating method is used extensively in environmental sciences and in human sciences such as archaeology and anthropology.It also has some applications in geology; its importance in dating organic materials cannot be underestimated enough.

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This discovery meant that there are three naturally occurring isotopes of carbon: Whereas carbon-12 and carbon-13 are stable isotopes, carbon-14 is unstable or radioactive.How do scientists know how old an object or human remains are?What methods do they use and how do these methods work?In 1979, Desmond Clark said of the method “we would still be foundering in a sea of imprecisions sometime bred of inspired guesswork but more often of imaginative speculation” (3).Radiocarbon dating may only be used on organic materials.It is used in dating things such as bone, cloth, wood and plant fibers that were created in the relatively recent past by human activities. Since carbon is fundamental to life, occurring along with hydrogen in all organic compounds, the detection of such an isotope might form the basis for a method to establish the age of ancient materials.In this article, we will examine the methods by which scientists use radioactivity to determine the age of objects, most notably carbon-14 dating.Carbon-14 dating is a way of determining the age of certain archeological artifacts of a biological origin up to about 50,000 years old.Carbon-14 is produced in the upper atmosphere when cosmic rays bombard nitrogen atoms.The ensuing atomic interactions create a steady supply of c14 that rapidly diffuses throughout the atmosphere. Libby, a Professor of Chemistry at the University of Chicago, predicted that a radioactive isotope of carbon, known as carbon-14, would be found to occur in nature.Working with several collaboraters, Libby established the natural occurrence of radiocarbon by detecting its radioactivity in methane from the Baltimore sewer.Later called Ötzi the Iceman, small samples from his body were carbon dated by scientists.The results showed that Ötzi died over 5000 years ago, sometime between 33 BC. It is found in the air in carbon dioxide molecules.




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