How did willard libby discover carbon dating

16 Jan

Because the activity of the carbon atoms decreases at a known rate, it should be possible, by measuring the remaining activity, to determine the time elapsed since death, if this occurred during the period between approximatively 500 and 30,000 years ago.This hypothesis was published by Libby in 1947, and with his great experimental skill it did not take him long to prove the validity of the theory.Professor Willard Libby has been selected to be the prize-winner for his method of age determination of materials of biological origin by use of carbon-14 as a measurer of time.His method has obtained widespread use and has become indispensable in archaeology, geology, geophysics and other sciences.Traces of the first human habitations in these regions were dated to about 10,000 years ago.In the southern part of France, on the other hand, beyond the advance of the ice, remnants were found of charcoal from the campfires of human cave-dwellers, remnants which proved to be 15,000 years old.It is converted into nitrogen by the emission of an electron which can be detected by a sensitive apparatus.

Fossil material, such as petroleum, was completely inactive; it comes from organisms which lived millions of years ago.

These first control experiments were preceded by a complicated enrichment procedure, but thanks to Libby's experience in working with lowactivity substances, he succeeded in refining the activity measurements so that the preliminary concentration procedures became unnecessary.

If this had not been possible, his method of age-determination would not have turned out to be the important tool for the advancement of science it has now become.

It is formed high up in the atmosphere by cosmic radiation coming from outer space. The newly formed carbon-14 has high energy at the moment of its formation, so that it rapidly oxidizes to carbon dioxide, which spreads out and distributes itself evenly in the atmosphere.

The ratio of carbon-14 in the carbon dioxide of the atmosphere is very low.