How Does Carbon Dating Work
How Does Carbon Dating Work?
How does carbon dating work? Carbon-14 produced in our outer atmosphere as Nitrogen-14 is changed into radioactive Carbon-14 by cosmic-ray bombardment. Radioactive Carbon-14 is unstable, decaying into Carbon-12 over a period of time. The "half life" of Carbon-14 is approximately 5,730 years. This means that in 5,370 years, half of an original quantity of Carbon-14 will decay into Carbon-12. Half of the remaining quantity will decay into Carbon-12 in another 5,370 years (thus, in 10,740 years only 1/4 of the original quantity of Carbon-14 will remain).
Again, half of the remaining quantity will decay into Carbon-12 in another 5,370 years and so on. Plants synthesize Carbon-14 in the form of Carbon Dioxide. Thus, Carbon-14 enters the food chain through plants. Animals eat the plants and thus absorb Carbon-14. When an organism dies, it no longer absorbs Carbon-14, and the existing Carbon-14 decays into Carbon-12.
Thus, it is thought that by measuring the ratio of Carbon-14 to Carbon-12 found within the remains of deceased organic matter and comparing that ratio to the ratio of Carbon-14 to Carbon-12 found in the atmosphere, we can determine the approximate date that an organism died.
How Does Carbon Dating Work? The Controversy
This dating technique assumes that Carbon-14 has reached equilibrium in our atmosphere—that is, the production rate is equal to the decay rate. Recent studies indicate that Carbon-14 has not yet reached equilibrium. There is more Carbon-14 in our atmosphere today than there was at any time in the past. Thus, Carbon Dating is controversial. If there's more Carbon-14 in the atmosphere today than there was 50 years ago, then a specimen that died 100 years ago would test at an artificially higher age.