Carbon dating used
This means that although they are very similar chemically, they have different masses.The total mass of the isotope is indicated by the numerical superscript.Carbon dating is used by archeologists to date trees, plants, and animal remains; as well as human artifacts made from wood and leather; because these items are generally younger than 50,000 years.
Professor Willard Libby produced the first radiocarbon dates in 1949 and was later awarded the Nobel Prize for his efforts.
The uncalibrated date is given with the unit BP (radiocarbon years before 1950).
The calibrated date is also presented, either in BC or AD or with the unit cal BP (calibrated before present - before 1950).
While the lighter isotopes C has decayed that what remains can no longer be measured. In 5,730 years half of the C in the atmosphere, and therefore in plants and animals, has not always been constant.
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.Geologists measure the abundance of these radioisotopes instead to date rocks.