Carbon Dating 14

Carbon dating 14

Carbon-14 dating is a way of determining the age of certain archaeological artefacts of a biological origin up to about 50,000 years old. It is used in dating things such as bone, cloth, wood and plant that were created in the quite recent past by human activities. Carbon-14 is a radioactive isotope of carbon (it has two extra neutrons in its nucleus making it unstable).

http://s.hswstatic.com/gif/carbon-14.gifAt an ar­chaeological dig, a piece of wooden tool is unearthed and the archaeologist finds it to be 5,000 years old. What methods do they use and how do these methods work? In this article, we will examine the methods by which scientists use radioactivity to determine the age of objects, most notably carbon-14 dating.

There's a small amount of radioactive carbon-14 in all living organisms. The amount of carbon-14 in the atmosphere has not changed in thousands of years. Even though it decays into nitrogen, new carbon-14 is always being formed when cosmic rays hit atoms high in the atmosphere. When they die no new carbon-14 is taken in by the dead organism. The carbon-14 it contained at the time of death decays over a long period of time. By measuring the amount of carbon-14 left in dead organic material the approximate time since it died can be worked out.

Because the half-life of carbon-14 is 5,700 years, it is only reliable for dating objects up to about 60,000 years old. However, the principle of carbon-14 dating applies to other isotopes as well. Potassium-40 is another radioactive element naturally found in your body and has a half-life of 1.3 billion years.

The use of various radioisotopes allows the dating of biological and geological samples with a high degree of accuracy. However, radioisotope dating may not work so well in the future. Anything that dies after the 1940s, when Nuclear bombs, nuclear reactors and open-air nuclear tests started changing things, it got harder to date precisely.