When did libby discover carbon dating
Also, the larger the sample the better, although new techniques mean smaller samples can sometimes be tested more effectively.The data can be a little off particularly in younger artifacts, and anything older than about 50,000 years is pretty much too old to be tested because at that point the majority of the C-14 has decayed to practically undetectable levels.Delicate operations were needed to extract a microscopic sample and process it.To get a mass large enough to handle, you needed to embed your sample in another substance, a "carrier." At first acetylene was used, but some workers ruefully noted that the gas was "never entirely free from explosion, as we know from experience."(4) Ways were found to use carbon dioxide instead.But now archaeologists studying, say, the development of agriculture across the continents are able to determine how different societies stacked up against one another throughout the millennia.Climate science required the invention and mastery of many difficult techniques.The excavator might employ relative dating, using objects located stratigraphically (read: buried at the same depth) close to each other, or he or she might compare historical styles to see if there were similarities to a previous find.
By 1950, Willard Libby and his group at the University of Chicago had worked out ways to measure this proportion precisely.Tricks also spread through visits between laboratories and at meetings, and sometimes even through publications.Any contamination of a sample by outside carbon (even from the researcher's fingerprints) had to be fanatically excluded, of course, but that was only the beginning.Frustrating uncertainties prevailed until workers understood that their results had to be adjusted for the room's temperature and even the barometric pressure.This was all the usual sort of laboratory problem-solving, a matter of sorting out difficulties by studying one or another detail systematically for months.