Notes on carbon dating
magazine has been continuously published since 1978, we are publishing some of the articles from the archives for historical interest, such as this.For teaching and sharing purposes, readers are advised to supplement these historic articles with more up-to-date ones suggested in the Related Articles below.Carbon-14 reacts identically to Carbon-12 and is rapidly oxidised to form (Carbon-14)Dioxide.Since all living organisms on Earth are made up of organic molecules that contain Carbon atoms derived from the atmosphere, they therefore contain Carbon-14 atoms.
Over time there is a gradual decrease in the amount of Carbon-14 and the ratio of Carbon-14 atoms to other Carbon atoms declines. Therefore half of the Carbon-14 has decayed after 5730 years.Libby thus reasoned that by measuring carbon 14 levels in the remains of an organism that died long ago, one could estimate the time of its death.This procedure of radiocarbon dating has been widely adopted and is considered accurate enough for practical use to study remains up to 50,000 years old.The layers of sedimentary rock, or strata, can be seen as horizontal bands of differently colored or differently structured materials exposed in this cliff.The deeper layers are older than the layers found at the top, which aids in determining the relative age of fossils found within the strata. Such index fossils must be distinctive, globally distributed, and occupy a short time range to be useful.