Effective range of radiocarbon dating
By measuring the ratio of the radio isotope to non-radioactive carbon, the amount of carbon-14 decay can be worked out, thereby giving an age for the specimen in question.But that assumes that the amount of carbon-14 in the atmosphere was constant — any variation would speed up or slow down the clock.
Since the 1960s, scientists have started accounting for the variations by calibrating the clock against the known ages of tree rings.
The half life of carbon-14 is about 5,700 years, so if we measure the proportion of C-14 in a sample and discover it's half a part per trillion, i.e.
half the original level, we know the sample is around one half life or 5,700 years old.
A wide range of sample types can be submitted for dating.
We can advise on the suitability of different materials and the most effective pretreatments.
It is in knowing what made past cultures cease to exist that could provide the key in making sure that history does not repeat itself.