Absolute dating is a method of determining the specific date of a paleontological or archaeological artifact or location based on a specific time scale or calendar. Scientists base absolute dating on measurable physical or chemical changes or on written records of events.
In the field of archeology, the term "absolute" is somewhat misleading. Chronometric or calendar dating is a better choice. Using these methods, the scientist determines a date range for when an event took place rather than where it fits in the overall record. They do not necessarily determine a specific date. The techniques scientist need for absolute dating did not become available until the later half of the 20th century.
Absolute dating uses clues, such as the emperor's face on a coin, to date an artifact. Tree ring dating offers over 1,000 years of clues in dates of artifacts from the American Southwest. Radiocarbon dating provides additional clues necessary for absolute dating.
Relative dating is an older method of placing events on the calendar of time. Artifacts from the earliest dates are in the lower levels or strata of Earth. With the passing of time, new strata form over them. Thus, the date of an artifact is relative to its location in the levels.