Number 14 carbon 14 dating denotes amount
Fortunately, neither effect has been significant in the case of older samples submitted for carbon-14 dating.
The ultimate cause of carbon-14 variations with time is generally attributed to temporal fluctuations in the cosmic rays that bombard the upper atmosphere and create terrestrial carbon-14.
And, if so, has today’s uniform level prevailed throughout the recent past?
After showing the essential uniformity of carbon-14 in living material, Libby sought to answer the second question by measuring the radiocarbon level in organic samples dated historically—materials as old as 5,000 years from sources such as Egyptian tombs.
Newly created carbon-14 atoms were presumed to react with atmospheric oxygen to form ) molecules.
Radioactive carbon thus was visualized as gaining entrance wherever atmospheric carbon dioxide enters—into land plants by photosynthesis, into animals that feed on the plants, into marine and fresh waters as a dissolved component, and from there into aquatic plants and animals.
Among them are the removal of humic acids from charcoal and the isolation of cellulose from wood and collagen from bone.
The discovery of natural Willard Libby of the United States began with his recognition that a process that had produced radiocarbon in the laboratory was also going on in Earth’s upper atmosphere—namely, the bombardment of nitrogen by free neutrons.In short, all parts of the carbon cycle were seen to be invaded by the isotope carbon-14.Invasion is probably not the proper word for a component that Libby calculated should be present only to the extent of about one atom in a trillion stable carbon atoms.The occurrence of natural radioactive carbon in the atmosphere provides a unique opportunity to date organic materials as old as roughly 60,000 years.Unlike most isotopic dating methods, the conventional carbon-14 dating technique is not based on counting daughter isotopes.