Carbon dating range accuracy - What s the effective range of Carbon dating? | Yahoo Answers


Consider the dating of a piece of wood. As long as the tree lives, it absorbs carbon from the atmosphere in the form of carbon dioxide, both C-12 and C-14. Once the tree dies, it ceases to take in new carbon, and any C-14 present begins to decay. The changing ratio of C-12 to C-14 indicates the length of time since the tree stopped absorbing carbon, ., the time of its death.

The measurement of the rate of radioactive decay is known as its half-life, the time it takes for half of a sample to decay. Libby calculated the half-life of c14 as 5568 ± 30 years. This means that half of the c14 has decayed by the time an organism has been dead for 5568 years, and half of the remainder has decayed by 11,136 years after death, etc. The diminishing levels via decay means that the effective limit for using c14 to estimate time is about 50,000 years. After this time, there is little if any c14 left. Subsequent work has shown that the half-life of radiocarbon is actually 5730 ± 40 years, a difference of 3% compared to the Libby half-life. However, to avoid confusion all radiocarbon laboratories continue to use the half-life calculated by Libby, sometimes rounding it to 5570 years.


Carbon dating range accuracy

Carbon dating range accuracy