Concept radiometric dating
Isotopes of a particular element have the same number of protons in their nucleus, but different numbers of neutrons.
Because of this, radiocarbon chemists are continually developing new methods to more effectively clean materials.
Radioactive decay can be used as a “clock” because it is unaffected by physical (e.g. For instance, the amount varies according to how many cosmic rays reach Earth.
This is affected by solar activity and the earth’s magnetic field.
Luckily, we can measure these fluctuations in samples that are dated by other methods.
Tree rings can be counted and their radiocarbon content measured.
In this way large domed tombs (known as tholos or beehive tombs) in Greece were thought to predate similar structures in the Scottish Island of Maeshowe.