If we know what fraction of the carbon atoms are radioactive, we can also calculate how many radiocarbon atoms are in the lump.
Knowing the number of atoms that decayed in our sample over a month, we can calculate the radiocarbon decay rate.
The reason is that, as long as the organism is alive, it replaces any carbon molecule that has decayed into nitrogen.
After plants and animals perish, however, they no longer replace molecules damaged by radiocarbon decay.
Thus it appears that God probably created those elements when He made the original earth.
In contrast, radiocarbon forms continually today in the earth’s upper atmosphere.
The standard way of expressing the decay rate is called the half-life.5 It’s defined as the time it takes half a given quantity of a radioactive element to decay.
So if we started with 2 million atoms of carbon-14 in our measured quantity of carbon, then the half-life of radiocarbon would be the time it takes for half, or 1 million, of those atoms to decay.It’s assumed to be the same number of carbon-14 atoms as in elephants living today.With time those sand grains fall to the bottom bowl, so the new number represents the carbon-14 atoms left in the mammoth skull when we found it.We can measure in the laboratory how many carbon-14 atoms are still in the skull.If we assume that the mammoth originally had the same number of carbon- 14 atoms in its bones as living animals do today (estimated at one carbon-14 atom for every trillion carbon-12 atoms), then, because we also know the radiocarbon decay rate, we can calculate how long ago the mammoth died. This dating method is similar to the principle behind an hourglass.6 The sand grains that originally filled the top bowl represent the carbon-14 atoms in the living mammoth just before it died.The radiocarbon half-life or decay rate has been determined at 5,730 years.