It is a technique that can yield absolute dates with accuracy up to approximately 5000 years before present.However its application has caused extreme confusion and misunderstanding of the archaeological record.
There are three forms of carbon that naturally occur forming the building blocks of all plant and animal life.
The stable C12 and C13, and the unstable or radioactive Carbon 14. Only one C14 atom exists for every one trillion C12 atoms.
You probably have seen or read news stories about fascinating ancient artifacts.
At an archaeological dig, a piece of wooden tool is unearthed and the archaeologist finds it to be 5,000 years old.
As plants enter the human and animal food chains the C14 dioxide enters their living tissue.
As with any radioactive particle it decays over time. Libby in 1948 at the University of Chicago, showed that C14, tested in his laboratory, decayed at the rate that, projected out, would cause half of its weight to be lost in 5568 years.A child mummy is found high in the Andes and the archaeologist says the child lived more than 2,000 years ago.How do scientists know how old an object or human remains are?Nitrogen atoms in the upper atmosphere are struck by cosmic radiation and create C14 atoms.These atoms rapidly decay into radiocarbon-dioxide and along with ordinary CO2 are absorbed by living plants.Archaeologists can use this method to date bone, teeth, plants, seeds, burned food remains, coprolites, wood, and any artefact that contains organic materials such as an iron axe head (iron cannot be tested using C14) with a wooden handle or a bronze spear with a wooden shaft.