C 14 carbon dating
The ratio of normal carbon (carbon-12) to carbon-14 in the air and in all living things at any given time is nearly constant.
Maybe one in a trillion carbon atoms are carbon-14.
The atomic number corresponds to the number of protons in an atom.
Atomic mass is a combination of the number of protons and neutrons in the nucleus.
Radiocarbon present in molecules of atmospheric carbon dioxide enters the biological carbon cycle: it is absorbed from the air by green plants and then passed on to animals through the food chain.The carbon-14 method was developed by the American physicist Willard F. It has proved to be a versatile technique of dating fossils and archaeological specimens from 500 to 50,000 years old.The method is widely used by Pleistocene geologists, anthropologists, archaeologists, and investigators in related fields.There are two main applications for radiometric dating.One is for potentially dating fossils (once-living things) using carbon-14 dating, and the other is for dating rocks and the age of the earth using uranium, potassium and other radioactive atoms.