A child mummy is found high in the Andes and the archaeologist says the child lived more than 2,000 years ago.
How do scientists know how old an object or human remains are?
The carbon-14 atoms combine with oxygen to form carbon dioxide, which plants absorb naturally and incorporate into plant fibers by photosynthesis.
Radiocarbon dating is a method of estimating the age of organic material.
It was developed right after World War II by Willard F.
Age determinations can also be obtained from carbonate deposits such as calcite, dissolved carbon dioxide, and carbonates in ocean, lake, and groundwater sources.
Cosmic rays enter the earth's atmosphere in large numbers every day and when one collides with an atom in the atmosphere, it can create a secondary cosmic ray in the form of an energetic neutron.
In order to date the artifact, the amount of Carbon-14 is compared to the amount of Carbon-12 (the stable form of carbon) to determine how much radiocarbon has decayed.
The ratio of carbon-12 to carbon-14 is the same in all living things.Libby and coworkers, and it has provided a way to determine the ages of different materials in archeology, geology, geophysics, and other branches of science.Some examples of the types of material that radiocarbon can determine the ages of are wood, charcoal, marine and freshwater shell, bone and antler, and peat and organic-bearing sediments.But that assumes that the amount of carbon-14 in the atmosphere was constant — any variation would speed up or slow down the clock.The clock was initially calibrated by dating objects of known age such as Egyptian mummies and bread from Pompeii; work that won Willard Libby the 1960 Nobel Prize in Chemistry.To measure the amount of radiocarbon left in a artifact, scientists burn a small piece to convert it into carbon dioxide gas.