Carbon Dating Method

In News 

• The District Court in Varanasi allowed a petition seeking Carbon Dating of the structure inside the Gyanvapi mosque that the Hindu side has claimed is a ‘Shivling’.

What is Carbon dating?

• It is a widely-used method applied to establish the age of organic material, things that were once living. 
  • Living things have carbon in them in various forms. 
• The dating method makes use of the fact that a particular isotope of carbon called C-14, with an atomic mass of 14, is radioactive, and decays at a rate that is well known.
  • The most abundant isotope of carbon in the atmosphere is carbon-12 or a carbon atom whose atomic mass is 12. 
    • A very small amount of carbon-14 is also present.
• Process : Plants get their carbon through the process of photosynthesis, while animals get it mainly through food. Because plants and animals get their carbon from the atmosphere, they too acquire carbon-12 and carbon-14 isotopes in roughly the same proportion as is available in the atmosphere.
  • when they die, the interactions with the atmosphere stop. 
  • Now, carbon-12 is stable and does not decay, while carbon-14 is radioactive. Carbon-14 reduces to one-half of itself in about 5,730 years.
    • This is what is known as its ‘half-life’.
  • So, after a plant or animal dies, the ratio of carbon-12 to carbon-14 in the body, or its remains, begins to change.
  •  This change can be measured and can be used to deduce the approximate time when the organism died.

Application

• Though extremely effective, carbon dating cannot be applied in all circumstances.
•  Specifically, it cannot be used to determine the age of non-living things, like rocks, for example. Also, the age of things that are more than 40,000-50,000 years cannot be arrived at through carbon dating. 
• There are other methods to calculate the age of inanimate things, but carbon dating can also be used in an indirect way in certain circumstances. For example, the age of the ice cores in glaciers and polar regions is determined using carbon dating by studying the carbon dioxide molecules trapped inside large ice sheets.

Source:IE