Phrased simply, radioactive dating is the method that uses measurements relating to the radioactivity of the atoms in a fossil or an artifact. What "decay" means is that the atoms in the object or body become unstable, and, over time, begin to "decompose" by giving off radiation in the forms of subatomic particles (such as electrons and protons).
The analogy is that a single species of fossil has a range of existence through geologic time just like an individual has a range of existence through a shorter period of time.
Reconstructing the actual evolutionary ranges of different fossil species through time and comparing them to each other is like comparing the life ranges of the relatives in your family tree.
Once you know their age ranges relative to each other, you can put relative age dates on records (either government files, or in the case of fossils, sediment cores), arrange them in order of oldest to youngest, and determine if there is any missing time (in either the government records or the sediment cores).
Now that you have looked at 'relative' age dating using a family tree, you will next look at a similar set of data using fossils retrieved from Ocean Drilling Program (ODP) cores of sediment from the Marion Plateau, part of the Great Barrier Reef of Australia.
You will analyze a range chart and find the important fossil events used in this part of the geologic section to determine the age of the cores.
Using a variety of reference material, you will assign ages to these fossil events.
Finally, you will examine the stratigraphy of the cores to look for discontinuities and other features by constructing an age-depth plot of the data.
In palaeontology and archaeology, it becomes necessary to determine the age of an artifact or fossil when it is uncovered.
This, of course, is so that it can be properly catalogued, and, if valid, can be related to or associated with other objects from the same era. Fossils and artifacts don't come with labels attached that clearly state their age.
Therefore, scientists need to make use of proper techniques to adequately specify what the age of a fossil or artifact is.
Two of the most well-known and most frequently used include radioactive dating and relative dating. Organic bodies, such as you and me, as well as inanimate objects, such as stone tablets or rocks.