Radioactive isotopes archaeological dating
The radiation emitted by some radioactive substances can be used to kill microorganisms on a variety of foodstuffs, which extends the shelf life of these products.Produce such as tomatoes, mushrooms, sprouts, and berries are irradiated with the emissions from cobalt-60 or cesium-137.
We know these steps because researchers followed the progress of the radioactive carbon-14 throughout the process.A similar sample of fresh bone gives a count rate of 19 counts per minute. The activity A of a sample is proportional to the number of radioactive atoms within it.Radioactive isotopes have a variety of applications.A comparison between the carbon date and that due the tree rings is shown in the diagram.Example problems A piece of bone from an archaeological site is found to give a count rate of 15 counts per minute.Shroud of Turin In 1989, several groups of scientists used carbon-14 dating to demonstrate that the age of the Shroud of Turin was only 600–700 y.
Many people still cling to a different notion, despite the scientific evidence.
Carbon-14 (half-life is 5,370 y) is particularly useful in determining the age of once-living artifacts (e.g., animal or plant matter).
A tiny amount of carbon-14 is produced naturally in the upper reaches of the atmosphere, and living things incorporate some of it into their tissues, building up to a constant, although very low, level.
For example if you consider the uranium series that the final stable isotope is lead-206, and if we assume that there was no lead in the rock when it was formed the ratio of the number of atoms of lead 206 (N The carbon 14 is then absorbed by plants; these in turn are eaten by animals which may then be eaten by other animals.
As soon as the animal dies the intake of radioactive carbon-14 stops and the proportion in the body starts to decrease.
Contrary to the belief of some people, irradiation of food make the food itself radioactive.