Fossil radioactive dating
There's a small amount of radioactive carbon-14 in all living organisms.
When they die no new carbon-14 is taken in by the dead organism.
Sometimes, scientists already know the age of the fossil because fossils of the same species have been found elsewhere and it has been possible to establish accurately from those when the dinosaur lived.
Geologists call this the principle of lateral continuity.
This technique is widely used on recent artifacts, but educators and students alike should note that this technique will not work on older fossils (like those of the dinosaurs alleged to be millions of years old).
This technique is not restricted to bones; it can also be used on cloth, wood and plant fibers.
The results showed that Ötzi died over 5000 years ago, sometime between 33 BC. Uranium has a very long half-life and so by measuring how much uranium is left in a rock its approximate age can be worked out.
Our understanding of the shape and pattern of the history of life depends on the accuracy of fossils and dating methods.
Levels of carbon-14 become difficult to measure and compare after about 50,000 years (between 8 and 9 half lives; where 1% of the original carbon-14 would remain undecayed).Darwin and his contemporaries could never have imagined the improvements in resolution of stratigraphy that have come since 1859, nor guessed what fossils were to be found in the southern continents, nor predicted the huge increase in the number of amateur and professional paleontologists worldwide.Carbon dating is used to determine the age of biological artifacts up to 50,000 years old.A process for determining the age of an object by measuring the amount of a given radioactive material it contains.If one knows how much of this radioactive material was present initially in the object (by determining how much of the material has decayed), and one knows the half-life of the material, one can deduce the age of the object.