Half lives used carbon dating
In the case of radiocarbon dating, the half-life of carbon 14 is 5,730 years.This half life is a relatively small number, which means that carbon 14 dating is not particularly helpful for very recent deaths and deaths more than 50,000 years ago.Archaeologists use the exponential, radioactive decay of carbon 14 to estimate the death dates of organic material.The stable form of carbon is carbon 12 and the radioactive isotope carbon 14 decays over time into carbon 12 and other particles.When an organism dies it ceases to replenish carbon in its tissues and the decay of carbon 14 to carbon 12 changes the ratio of carbon 12 to carbon 14.
When finding the age of an organic organism we need to consider the half-life of carbon 14 as well as the rate of decay, which is –0.693.
For example, say a fossil is found that has 35% carbon 14 compared to the living sample. We can use a formula for carbon 14 dating to find the answer.
After 5,730 years, the amount of carbon 14 left in the body is half of the original amount.
If the amount of carbon 14 is halved every 5,730 years, it will not take very long to reach an amount that is too small to analyze.
Radiocarbon dating can be used on samples of bone, cloth, wood and plant fibers.
The half-life of a radioactive isotope describes the amount of time that it takes half of the isotope in a sample to decay.