Chemical workings of carbon dating
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Free 5-day trial Ever wondered how scientists know the age of old bones in an ancient site or how old a scrap of linen is?
The technique used is called carbon dating, and in this lesson we will learn what this is and how it is used. Carbon dating, or radiocarbon dating, is a method used to date materials that once exchanged carbon dioxide with the atmosphere. In the late 1940s, an American physical chemist named Willard Libby first developed a method to measure radioactivity of carbon-14, a radioactive isotope.
Libby was awarded the Nobel Prize in chemistry for his work in 1960.
For the record, a beta-particle is a specific type of nuclear decay. Image 1 shows carbon-14 production by high energy neutrons hitting nitrogen-14 atoms, while in Image 2, carbon-14 naturally decomposes through beta-particle production.Once they die, they stop taking in carbon-14, and the amount present starts to decrease at a constant half-life rate.Then the radiocarbon dating measures remaining radioactivity.You will notice that after around 40,000 years (or 8 half-lives), the amount left is starting to become very small, less than 1%.Scientists often use the value of 10 half-lives to indicate when a radioactive isotope will be gone, or rather, when a very negligible amount is still left.
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By measuring the amount of carbon-14 left in the organism, it's possible to work out how old it is.