Carbon-14 dating, also known as radiocarbon dating, is a scientific method that can accurately determine the age of organic materials as old as approximately 60,000 years. It is based on the fact that living organisms absorb carbon-14 into their tissue, and when they die, the carbon-14 starts to change into other atoms over time. Scientists can estimate how long the organism has been dead by counting the remaining carbon-14 atoms. Here are some key points about carbon-14 dating:
- Carbon-14 is an isotope of the element carbon that is unstable and weakly radioactive.
- Carbon-14 is continually being formed in the upper atmosphere by the effect of cosmic ray neutrons on nitrogen-14 atoms.
- Plants and animals assimilate carbon-14 from carbon dioxide throughout their lifetimes. When they die, they stop exchanging carbon with the biosphere and their carbon-14 content then starts to decrease at a rate determined by the law of radioactive decay.
- Carbon-14 dating has been used for historical studies, atmospheric science, and archaeology.
- The technique was developed in the late 1940s at the University of Chicago by chemistry professor Willard Libby, who would later receive the Nobel Prize for the work.
- Carbon-14 dating has proved to be a versatile technique of dating fossils and archaeological specimens from 500 to 50,000 years old.
- There are three principal techniques used to measure carbon-14 content of any given sample— gas proportional counting, liquid scintillation counting, and accelerator mass spectrometry.
- Forensic scientists use carbon-14 measurement to determine the year of birth or death of an organism from which the tissue was derived.
- Carbon-14 dating can be used to determine the age of everything from human body parts like bones to plant fibers, wood, and pollen.
