The ratio of normal carbon (carbon-12) to carbon-14 in the air and in all living things at any given time is nearly constant.
Maybe one in a trillion carbon atoms are carbon-14.
(For brevity's sake, hereafter I will refer to the parent isotope as ).
In addition, it requires that these measurements be taken from several different objects which all formed at the same time from a common pool of materials.
Ninety-five percent of the activity of Oxalic Acid from the year 1950 is equal to the measured activity of the absolute radiocarbon standard which is 1890 wood.
This is the International Radiocarbon Dating Standard.
However, the methods must be used with care -- and one should be cautious about investing much confidence in the resulting age...
especially in absence of cross-checks by different methods, or if presented without sufficient information to judge the context in which it was obtained.
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).
er et grundstof med atomnummer 6 i det periodiske system med symbolet C.
I det periodiske system er det det første (i række 2) af seks elementer i gruppe 14, som har sammensætningen af deres ydre elektronskal til fælles.
Carbons fysiske egenskaber kan variere voldsomt, afhængig af dets allotropiske form.
For eksempel er grafit opak og sort, mens diamant er meget transparent.