Radiocarbon dating can be used on samples of bone, cloth, wood and plant fibers.The half-life of a radioactive isotope describes the amount of time that it takes half of the isotope in a sample to decay.Another standard, Oxalic Acid II was prepared when stocks of HOx 1 began to dwindle. The ratio of the activity of Oxalic acid II to 1 is 1.29330.001 (the weighted mean) (Mann, 1983). There are other secondary radiocarbon standards, the most common is ANU (Australian National University) sucrose.The ratio of the activity of sucrose with 0.95 Ox was first measured by Polach at 1.50070.0052 (Polach, 1976b:122).It has been determined that the rate of radioactive decay is first order.
You can get an idea of the relationship between C14 and age at the Carbon Dating calculator page. 1950 was chosen for no particular reason other than to honour the publication of the first radiocarbon dates calculated in December 1949 (Taylor, 19)., where r is a measurement of the rate of decay, k is the first order rate constant for the isotope, and N is the amount of radioisotope at the moment when the rate is measured.The rate of decay is often referred to as the activity of the isotope and is often measured in Curies (Ci), one curie = 3.700 x 10" is the initial amount of radioisotope at the beginning of the period, and "k" is the rate constant for the radioisotope being studied.Outside the range of recorded history, calibration of the 14 clock is not possible.This means the above calculations are only evolution speculation and NOT backed up by real science.