During their lifetime, all plants and
animals in the world absorb radioactive carbon atoms. These atoms
are also called C-14 for carbon 14.
As these atoms decay (or die) they are
replaced by new ones, so the amount of radioactive carbon in our atmosphere
is always the same.
All living things keep on absorbing C-14
during life, but the process stops when the plant or animal dies.
After this, the C-14 in that plant or animal very slowly begins to disappear.
But, luckily for archaeologists, radiocarbon decays at a fairly steady
rate, it doesn't speed up or slow down
a whole lot, it just disappears steadily.
This rate has been calculated by scientists.
They know that C-14 has a half-life of 5730 years. After 5730 years,
the amount of C-14 that was in the organism at the time it died is half
decayed. After another 5730 years, half of that amount has decayed
and so on and so on. Because the amount of C-14 in the atmosphere
is always the same (or constant), the amount of C-14 which is left in the
dead animal or plant can tell us how much time has gone past since its
Radiocarbon dating can be used on a lot
of things that archaeologists recover from excavations. The best
is charcoal because it is made mainly of carbon. Other things have
to be reduced to their carbon content before dating can be carried out.
We can do radiocarbon dating on anything that was once living such as wood,
plant, human and animal bones, shells
and sometimes even pottery.
In a nutshell, all plants and animals
absorb radioactive carbon during their lifetimes. When they die,
the carbon 14 decays. After 5730 years, it has half the original
amount, after another 5730 it is a quarter the original amount and so on.
So, measurement of the carbon 14 content remaining can be used to date
any material that was once living.
PHEW!! IF YOU GOT THROUGH
THAT, YOU CAN GET THROUGH ANYTHING!!!!
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