Is dendrochronology absolute or relative dating Extreme adult chatrooms
The nucleus of every radioactive element (such as radium and uranium) spontaneously disintegrates over time, transforming itself into the nucleus of an atom of a different element.In the process of disintegration, the atom gives off radiation (energy emitted in the form of waves). Each element decays at its own rate, unaffected by external physical conditions.If a certain kind of pollen is found in an archaeological site, scientists can check when the plant that produced that pollen lived to determine the relative age of the site.Absolute dating methods are carried out in a laboratory.Since certain species of animals existed on Earth at specific times in history, the fossils or remains of such animals embedded within those successive layers of rock also help scientists determine the age of the layers.Similarly, pollen grains released by seed-bearing plants became fossilized in rock layers.The age of the remains of plants, animals, and other organic material can be determined by measuring the amount of carbon-14 contained in that material.Carbon-14, a radioactive form of the element carbon, is created in the atmosphere by cosmic rays (invisible, high-energy particles that constantly bombard Earth from all directions in space).
When a piece of pottery is heated in a laboratory at temperatures more than 930°F (500°C), electrons from quartz and other minerals in the pottery clay emit light.
When the organism dies, the supply stops, and the carbon-14 contained in the organism begins to spontaneously decay into nitrogen-14.
The time it takes for one-half of the carbon-14 to decay (a period called a half-life) is 5,730 years.
Before the advent of absolute dating methods in the twentieth century, nearly all dating was relative.
The main relative dating method is stratigraphy (pronounced stra-TI-gra-fee), which is the study of layers of rocks or the objects embedded within those layers.