Carbon 14 decay dating
How do scientists know how old an object or human remains are?What methods do they use and how do these methods work?
The stable form of carbon is carbon 12 and the radioactive isotope carbon 14 decays over time into nitrogen 14 and other particles.
Carbon14 has a halflife of 5,730 ± 40 years—, half the amount of the radioisotope present at any given time will undergo spontaneous disintegration during the succeeding 5,730 years.
Carbon 14 decay dating comments 

Carbon14  Wikipedia
paulette60

Carbon14 Dating  edu
paulette60

Carbon14 dating scientific technology
paulette60

Carbon 14 dating 1 video Khan Academy
paulette60

Carbon 14 Dating  Math Central
paulette60

How Carbon14 Dating Works HowStuffWorks
paulette60