Isotopes of a particular element have the same number of protons, but different numbers of neutrons.Different isotopes have different masses, because each neutron has some mass.However, cosmic radiation constantly collides with atoms in the upper atmosphere.Part of the result of these collisions is the production of radiocarbon (C, pronounced "c fourteen"), carbon atoms which are chemically the same as stable carbon, but have two extra neutrons.Scientists have debated for decades when these giant statues were built and why the civilization of Rapa Nui collapsed.
What methods do they use and how do these methods work?
Comparing the remaining 14C fraction of a sample to that expected from atmospheric 14C allows the age of the sample to be estimated.
The technique of radiocarbon dating was developed by Willard Libby and his colleagues at the University of Chicago in 1949. Libby estimated that the steady state radioactivity concentration of exchangeable carbon-14 would be about 14 disintegrations per minute (dpm) per gram.
In 1960, he was awarded the Nobel Prize in chemistry for this work.
These statues were made on Easter Island, also known as Rapa Nui, a tiny, remote, island in the Pacific Ocean, 2,000 miles away from Chile.