Absolute dating and relative dating
We define the rate of this radioactive decay in half-lives.
If a radioactive isotope is said to have a half-life of 5,000 years that means after 5,000 years exactly half of it will have decayed from the parent isotope into the daughter isotopes.
There are two main methods determining a fossils age, relative dating and absolute dating.
Relative dating is used to determine a fossils approximate age by comparing it to similar rocks and fossils of known ages.
Short Answer: Both relative dating and absolute dating are tools used to give temporal characteristics to a sequence of events.
Both are attempting to get information on the history of events.
Typically commonly occurring fossils that had a widespread geographic distribution such as brachiopods, trilobites, and ammonites work best as index fossils.
The majority of the time fossils are dated using relative dating techniques.
Scientists can use certain types of fossils referred to as index fossils to assist in relative dating via correlation.
Index fossils are fossils that are known to only occur within a very specific age range.
Relative dating is a scientific process of evaluation used to determine the relative order of past events, but does not determine the absolute age of an object.
Long Answer: Sciences such as geology, paleontology and archeology are very interested in identifying the age of objects found and these scientists sometimes use either relative dating or absolute dating to characterize the age of the objects they study.Tools like radiometric dating allow some samples to be assigned a certain age to within some accuracy.Assigning a certain age or date is a form of absolute dating.Before radiometric dating it was difficult to determine the actual age of an object.