Half life dating activity
BEFORE DECAY BEGINS, ALL OF THE MATERIAL IS RADIOACTIVEAFTER ONE HALF LIFE, HALF OF THE SAMPLE REMAINS RADIOACTIVE AND THE OTHER HALF IS STABLEAFTER EACH ADDITIONAL HALF LIFE, HALF OF THE REMAINING RADIOACTIVE MATERIAL DECAYSWe use several radioactive isotopes to find the absolute age of events and objects because we know their half life.
The older a sample is, the less (the period of time after which half of a given sample will have decayed) is about 5,730 years, the oldest dates that can be reliably measured by this process date to around 50,000 years ago, although special preparation methods occasionally permit accurate analysis of older samples.
Using the half life for carbon-14 and comparing the amount of carbon-14 in on ancient artifact with the amount of carbon-14 we would expect in a fresh sample today we can date an object.
The method was developed by Willard Libby in the late 1940s and soon became a standard tool for archaeologists.
The resulting data, in the form of a calibration curve, is now used to convert a given measurement of radiocarbon in a sample into an estimate of the sample's calendar age.
Other corrections must be made to account for the proportion of throughout the biosphere (reservoir effects).