Radio carbon dating made easy
: it is absorbed from the air by green plants and then passed on to animals through the food chain.
Radiocarbon decays slowly in a living organism, and the amount lost is continually replenished as ...
If carbon-14 has formed at a constant rate for a very long time and continually mixed into the biosphere, then the level of carbon-14 in the atmosphere should remain constant.
After plants and animals perish, however, they no longer replace molecules damaged by radiocarbon decay.When animals eat the plants, the carbon-14 enters their bodies.The carbon-14 in their bodies breaks down to nitrogen-14 and escapes at the same rate as new carbon-14 is added. CARBON-14 IS DEPLETED (Figure 1c): When an animal dies the carbon-14 continues to break down to nitrogen-14 and escapes, while no new carbon-14 is added.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.
Search for radio carbon dating made easy:
Instead, the radiocarbon atoms in their bodies slowly decay away, so the ratio of carbon-14 atoms to regular carbon atoms will steadily decrease over time (Figure 1c).