14c12c ratio carbon dating
Carbon dating is used to determine the age of biological artifacts up to 50,000 years old.
This technique is widely used on recent artifacts, but teachers should note that this technique will not work on older fossils (like those of the dinosaurs which are over 65 million years old).
Imagine your sample contained 20% of the carbon-14 found in a living plant leaf.
Then, First, carbon-14 cannot be used to date biological artifacts of organisms that did not get thier carbon dioxide from the air.
The ratio of carbon-14 to carbon-12 in the atmosphere and on earth is nearly constant, although there has been some change in carbon-14 concentration over the last 10,000 years.
If you wanted to date a fossil, first you would determine the percent carbon-14 it contained compared to a living sample.Scientists now realize that production of carbon-14 has not been constant over the last 10,000 years, but has changed as the radiation from the sun has changed.Carbon dates reported in the 1950s and 1960s should be questioned, because those studies were conducted before carbon dating was calibrated by comparision with other dating methods.This restriction extends to animals that consume seafood in their diets, as well.
Carbon dating also cannot be used on artifacts over about 50,000 years old.
At any given moment all living plants and animals have approximately the same percentage of carbon-14 in their bodies.