# How does Carbon-14 Dating Work?

Ever since its introduction more than 60 years ago by scientist Willard Libby, carbon-14 dating technique has been instrumental in determining the age of organic objects of historical and archeological origin.

ScienceStruck Staff

Last Updated: Nov 27, 2018

Did you know?

Carbon-14 dating technique has been successfully used on the Minoan ruins, Dead Sea Scrolls, and tombs of the Pharaohs.

How Carbon-14 is formed?

All living organisms and our environment are made of carbon. The most common form of carbon in the atmosphere is carbon-12, which is a stable isotope of carbon. An unstable form of carbon isotope, carbon-14, also known as radiocarbon, is formed when cosmic rays hit atoms in the upper atmosphere of the earth.

How Carbon-14 Dating Works

Plants get their share of carbon atoms from the atmosphere. Animals and humans get it from what they eat. It is seen that at any given point of time, the ratio of stable carbon and radiocarbon in the atmosphere, is almost same as the ratio of stable carbon and radiocarbon in living organisms like plants, animals, and humans.

Calculating with Carbon-14 Dating Technique

Formula to calculate the age of a sample by carbon-14 dating is as follows:

where,

**t = [ ln (N**_{f}/N_{o}) / (-0.693) ] x t_{1/2}where,

**ln**is the natural logarithm,**N**is the percentage of carbon-14 in the sample compared to that in a living sample,_{f}/N_{o}**t**is the half life of carbon-14,_{1/2}**t**is the age of the samplet = [ ln (.15) / (-.693) ] x 5700 years

= [ ln (-1.897) / (-.693) ] x 5700 years

= 1.3146 x 5700 years

= 7493 years old

Shortcomings

► Carbon dating can only be used to date objects up to 5700 years. Things older than that have only about 1% carbon-14 left in them and hence, it is not possible to calculate their age accurately.