![]() Complicating matters is the fact that Earth’s carbon-14 concentrations change drastically based on various factors. Scientists must assume how much carbon-14 was in the organism when it died. Carbon dating is based on the loss of carbon-14, so, even if the present amount in a specimen can be detected accurately, we must still know how much carbon-14 the organism started with. The other major factor affecting the results of carbon dating is gauging the original proportion of carbon-14 itself. ![]() As a result, carbon dating is only plausible for objects less than about 40,000 years old. Normal errors in the test become magnified. Carbon dating therefore relies on enrichment and enhancement techniques to make smaller quantities easier to detect, but such enhancement can also skew the test results. Tiny variations within a particular sample become significant enough to skew results to the point of absurdity. So even brand-new samples contain incredibly tiny quantities of radiocarbon.Įventually, the amount of carbon-14 remaining is so small that it’s all but undetectable. Carbon-14 normally makes up about 1 trillionth (1/1,000,000,000,000) of the earth’s atmosphere. When an organism dies, it stops taking in new carbon-14, and whatever is inside gradually decays into other elements. The bodies of living things generally have concentrations of the isotope carbon-14, also known as radiocarbon, identical to concentrations in the atmosphere. Second, radiocarbon dating becomes more difficult, and less accurate, as the sample gets older. This is perhaps the greatest point of potential error, as assumptions about dating can lead to circular reasoning, or choosing confirming results, rather than accepting a “wrong” date. If the spear head is dated using animal bones nearby, the accuracy of the results is entirely dependent on the assumed link between the spear head and the animal. This makes the results subject to the researchers’ assumptions about those objects. Most archaeological items can’t be directly carbon dated, so their dating is based on testing done on nearby objects or materials. Nor can it tell if a much older spearhead was attached to a brand-new shaft. Radiocarbon dating can’t tell the difference between wood that was cut and immediately used for the spear, and wood that was cut years before being re-used for that purpose. This provides good information, but it only indicates how long ago that piece of wood was cut from a living tree. For example, a steel spearhead cannot be carbon dated, so archaeologists might perform testing on the wooden shaft it was attached to. When testing an object using radiocarbon dating, several factors have to be considered:įirst, carbon dating only works on matter that was once alive, and it only determines the approximate date of death for that sample. Carbon dating is reliable within certain parameters but certainly not infallible. For this reason, it’s preferable to date objects using multiple methods, rather than relying on one single test. Several factors affect radiocarbon test results, not all of which are easy to control objectively. ![]() Carbon dating, or radiocarbon dating, like any other laboratory testing technique, can be extremely reliable, so long as all of the variables involved are controlled and understood.
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