Radio carbon
dating
A radio carbon or carbon -14, 14C, is a radioactive isotope of carbon, it is formed in the
atmosphere as a result of collision between cosmic rays and nucleus of atoms. Radiocarbon
is produced by the reaction of neutron with nitrogen in the air. The
radiocarbon created combine with atmospheric oxygen to form radioactive carbon(iv)oxide
. As shown by the equation below
14N + n = 14N + p where n and p are neutron and proton
respectively
14N
= 14N + -β
In the atmosphere
also there are carbon -12 isotope which is not radioactive therefore
non-radioactive carbon(iv)oxide are also formed in the atmosphere.
This radioactive carbon are absorbed by plant
during the process of photosynthesis, likewise herbivore animals that feed on
this plant will absorb and carnivores animal that feed on this herbivores will
also have this radiocarbon in their body.
When this
animal or plant dies the intake of carbon-14 stops and therefore exchange of
materials with its environment stops , the level of radiocarbon continue to
decrease by half every 5730 years .
By determining
the proportion of radiocarbon to ordinary carbon in their remains( bones, wood,
skull etc.), it is possible to evaluate
the ages of the ancient object of organic origins. With this method oldest
dates up to about 50, 000 years can be measured.
Measuring
carbon-14 from a sample can be done using beta counting devices, or an
accelerator mass spectrometer is used, the second device can count all
radiocarbon atom in the sample.
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