However, open-air nuclear testing between 1955–1980 contributed to this pool.
90% of the time, speakers of English use just 7,500 words in speech and writing.
These words appear in red, and are graded with stars.
The translations of radiocarbon from English to other languages presented in this section have been obtained through automatic statistical translation; where the essential translation unit is the word «radiocarbon» in English.
The graph expresses the annual evolution of the frequency of use of the word «radiocarbon» during the past 500 years.
Carbon-14 was discovered on 27 February 1940, by Martin Kamen and Sam Ruben at the University of California Radiation Laboratory in Berkeley.
Its existence had been suggested by Franz Kurie in 1934.
Atmospheric nuclear weapon tests almost doubled the concentration of Radiocarbon dating, also known as the C14 dating method, is a way of telling how old an object is. Plants take up atmospheric carbon dioxide by photosynthesis, and are eaten by animals, so every living thing is constantly exchanging carbon-14 with its environment as long as it lives. In 1958 Hessel de Vries showed that the concentration of carbon-14 in the atmosphere varies with time and locality.
Carbon has different isotopes, which are usually not radioactive; C is the radioactive one, its half-life, or time it takes to radioactively decay to one half its original amount, is about 5,730 years.
Click on the thesaurus category heading under the button in an entry to see the synonyms and related words for that Blog A must for anyone with an interest in the changing face of language.
Radiocarbon dating is one of the best known archaeological dating techniques available to scientists, and the many people in the general public have at least heard of it.
Bei diesen Prozessen findet eine sehr geringe Fraktionierung nach der Isotopenmasse statt (siehe unten), der Anteil an Radiokohlenstoff in Lebewesen ist also zunächst fast so wie in der Atmosphäre.