Radiocarbon dating is a method that provides objective age estimates for carbon-based materials that originated from living organisms. The impact of the radiocarbon dating technique on modern man has made it one of the most significant discoveries of the 20th century. Archaeology and other human sciences use radiocarbon dating to prove or disprove theories. Over the years, carbon 14 dating has also found applications in geology, hydrology, geophysics, atmospheric science, oceanography, paleoclimatology and even biomedicine. Radiocarbon, or carbon 14, is an isotope of the element carbon that is unstable and weakly radioactive.
How Does Carbon Dating Work
Nuclear Chemistry: Half-Lives and Radioactive Dating - dummies
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 nitrogen 14 and other particles. Carbon is naturally in all living organisms and is replenished in the tissues by eating other organisms or by breathing air that contains carbon. At any particular time all living organisms have approximately the same ratio of carbon 12 to carbon 14 in their tissues.
Radiometric dating is a means of determining the "age" of a mineral specimen by determining the relative amounts present of certain radioactive elements. By "age" we mean the elapsed time from when the mineral specimen was formed. Radioactive elements "decay" that is, change into other elements by "half lives. The formula for the fraction remaining is one-half raised to the power given by the number of years divided by the half-life in other words raised to a power equal to the number of half-lives.
Each element is a substance composed of atoms with an identical number of protons in their nuclei. For example, an atom of the element nitrogen always has seven protons. All elements except hydrogen also have neutrons in their nuclei, and the element's atomic weight is the sum of the weights of the protons and neutrons. The periodic table of the elements lists the atomic weight of each element, which is the weighted average of the isotope weights based on the abundance of each. You could easily look up the percent abundance of each isotope in a chemistry book or on the Web, but you may have to calculate the percent abundance by hand, for example, to answer a question on a chemistry test at school.