Range of carbon dating
You can get an idea of the relationship between C14 and age at the Carbon Dating calculator page.
Archaeology and other human sciences use radiocarbon dating to prove or disprove theories.
The Oxalic acid standard which was developed is no longer commercially available.
In the early 1980's, a group of 12 laboratories measured the ratios of the two standards.
Liquid scintillation counting is another radiocarbon dating technique that was popular in the 1960s.
In this method, the sample is in liquid form and a scintillator is added.
By knowing how much carbon 14 is left in a sample, the age of the organism when it died can be known.