Friday, April 13, 2012

What impact has the fossil dating tecnology made on the field of science?


Most methods of dating of artefacts are using techniques based on radioactive properties of certain chemicals. The best known method is based on radiocarbon dating, also known as carbon-14.
Carbon-14 dating allows age determination of biological origin artifacts, not older than 50-60 thousand years. The method is used in particular for dating bones, clothing items, wood and plant fiber products of human activity, in relatively recent past of the planet,from the archaeological point of view.
Carbon-14 which occurs as a result of interactions between Earth's atmosphere and cosmic radiation is combined with atmospheric oxygen giving rise to carbon dioxide atoms, which plants absorb it and store it in plant fibers by photosynthesis.Carbon atoms are present in nature as an overwhelming proportion of the isotope carbon-12, which is not radioactive.The proportion in which the two isotopes are scattered in nature is a constant, at least in the air and within living organisms, plants or animals.
About one in a trillion carbon atoms is of the carbon-14. Although carbon-14 atom decays with a half-life rate constant, cosmic radiation gives rise to others, and thereby preserve the ratio of carbon 14 and carbon-12 within living organisms. The ratio of carbon 14 and carbon-12 is the same for all people, and this proportion is kept in the plants or animals.
When a body dies, taking the carbon-14 from the atmosphere or from the plant or animal food ceases. Reasoning applies to plants, where photosynthesis does not occur. But the process of radioactive decay of carbon-14 already existing in the structure of dead bodies, whether animals or plants, continues.
If the isotope carbon-14 has a half-life of 5700 years, the amount of carbon-12 does not change even after the death of living organisms. Estimating the proportion of atoms of carbon-14 reported carbon-12 atoms in a sample taken from plant or animal remains unearthed in archaeological sites, scientists can estimate the age of the sample with a satisfactory accuracy, so the artifact or human remains, after case.








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