Anything that contains organic material can be carbon-dated.
The field of archaeology relies heavily upon radiocarbon dating. By looking at carbon found in discovered materials, objects and remains, scientists can approximate how old an item is. According to the BBC, carbon dating may be the most important scientific method utilized in archaeology today.
Basics
Simply, carbon dating can only be applied to objects that were once living or were attached to something that was once living. This includes human and animal body components (such as bones and flesh) and plant matter (such as leaves and wood). It cannot date inorganic material, such as rocks.
Carbon & C14
The backbone of all life on earth, carbon is present in all organisms on earth. One isotope of carbon --- C14 --- comes from the earth's atmosphere and becomes absorbed in plants through photosynthesis. C14, along with other isotopes of carbon, becomes part of the molecular composition of animals when they ingest plants. C14 is not a stable isotope, however, and decays at a relatively constant rate.
Radiocarbon Dating
Levels of C14 remain relatively constant during an organism's lifetime, but start to decay when the animal has died. Comparing the half-life of C14 to the amount present in a sample will determine how old an artifact is. Although accurate, the method of radiocarbon dating does not accurately determine the age of newer artifacts. In addition, according to the University of California, "the practical upper limit is about 50,000 years, because so little C-14 remains after almost 9 half-lives that it may be hard to detect and obtain an accurate reading, regardless of the size of the sample."
Application of Radiocarbon Dating
Beyond archeology, using C14 to date material has proven useful in fields including oceanography, geology, biomedicine, atmospheric science, and palaeoclimatology. Radiocarbon Web Info lists many items that can be carbon dated, including metal casting ores, blood residues, textiles and fabrics, water, leather, hair, iron, corals, paper and parchment, and charcoal. It has allowed professionals to determine historical chronologies of human and natural events.
Tags: carbon dating, once living, radiocarbon dating, relatively constant
