Radio carbon dating determines the age of ancient objects by means of measuring the amount of carbon-14 there is left in an object.A man called Willard F Libby pioneered it at the University of Chicago in the 50's. This is now the most widely used method of age estimation in the field of archaeology.
Looking at the graph, 100% of radiocarbon in a sample will be reduced to 50% after 5730 years.In 11,460 years, half of the 50% will remain, or 25%, and so on.As long as there is organic material present, radiocarbon dating is a universal dating technique that can be applied anywhere in the world.It is good for dating for the last 50,000 years to about 400 years ago and can create chronologies for areas that previously lacked calendars.However, radioisotope dating may not work so well in the future.
Anything that dies after the 1940s, when Nuclear bombs, nuclear reactors and open-air nuclear tests started changing things, will be harder to date precisely.
After an organism dies, the radiocarbon decreases through a regular pattern of decay. The time taken for half of the atoms of a radioactive isotope to decay in Carbon-14’s case is about 5730 years.
Half-lives vary according to the isotope, for example, Uranium-238 has a half-life of 4500 million years where as Nitrogen-17 has a half-life of 4.173 seconds!
In a stratigraphical context objects closer to the surface are more recent in time relative to items deeper in the ground.
Although relative dating can work well in certain areas, several problems arise.
Rodents, for example, can create havoc in a site by moving items from one context to another.