All living organisms have carbon in it. Carbon-14, a radioactive carbon component is also found in all living organisms in small quantities. By using this radio active component, scientists can easily determine the age of clothing and wood and anything that once lived or was alive. The method used to date any object with the help of carbon-14 in that organism is known as ‘radiocarbon dating’.
This technique commonly known as carbon-14 dating can be used to date objects as old as 50,000 years. All radioactive elements break down and the rate at which these radioactive substances break down is known as half-life. An objects half-life is the time that has been taken where half of the objects atoms breaks down.
Carbon-14 has a half-life of about five thousand five hundred years. If we do our maths right we can easily determine the exact date of death of an animal or plant or any object for that matter. In 5,500 years, half of the carbon-14 atoms originally present at the time of the death are present or half of the carbon-14 atoms had broken down.
Thus after eleven thousand years one-fourth(1/4th) of the carbon-14 atoms are left and after sixteen thousand five hundred years(16,500), one-eights(1/8th) of the original carbon-14 atoms are left. The calculation goes on and this is the reason we can estimate the age of any item up to 50,000 years. The actual dating of any object is done in a laboratory.
For example a piece of wood which is very old is found in an ancient tomb. This is brought to the lab and is heated and converted into carbon or it is burned which produces various types of gases that includes carbon dioxide. These carbon dioxide or carbon has few carbon-14 atoms that are breaking down constantly.
With every break down, a very minute particle is sent speeding out of the atom. The carbon dioxide or carbon is placed in a very sensitive instrument which is known as ‘Geiger Counter’. This instrument detects these particles which are exiting at high speeds i.e. it detects the carbon-14 atoms that are given off.
Scientists can determine the amount of carbon-14 left in an object by calculating the number of particles given off with the help of the Geiger counter. Similarly scientists can also determine the carbon-14 which is contained in a small piece of wood acquired from a living tree. But this technique is used for determining the age of ancient objects.
From the amount of carbon-14 left, scientists determine the age of the object. If half the amount of carbon-14 is left, then it means that the object is 5,500 years old. Scientists also use this technique to date the age of trees in rain forests so as to conserve them from further destruction by the human race.