The numbers of C14 atoms and non-radioactive carbon atoms remain approximately the same over time during the organism’s life.
The following material has been taken from a sheet entitled Several Faulty Assumptions Are Used in all Radiometric Dating Methods.
The argument may be compared to filling a barrel which has numerous small holes in its sides.
We stick the garden hose in and turn it on full blast.
So, we have a “clock” which starts ticking the moment something dies.
Obviously, this works only for things which were once living.
C-14 is produced in the upper atmosphere when nitrogen-14 (N-14) is altered through the effects of cosmic radiation bombardment (a proton is displaced by a neutron effectively changing the nitrogen atom into a carbon isotope).
The new isotope is called "radiocarbon" because it is radioactive, though it is not dangerous.
One radioactive, or unstable, carbon isotope is C14, which decays over time and therefore provides scientists with a kind of clock for measuring the age of organic material.The water leaking out the sides of the barrel represents the loss (mainly by radioactive decay) of the atmosphere's supply of carbon-14.Love-hungry teenagers and archaeologists agree: dating is hard.Familiar to us as the black substance in charred wood, as diamonds, and the graphite in “lead” pencils, carbon comes in several forms, or isotopes.One rare form has atoms that are 14 times as heavy as hydrogen atoms: carbon-14, or C ratio gets smaller.