Exponential decay carbon 14 dating formula

26 Nov

As you learned in the previous page, carbon dating uses the half-life of Carbon-14 to find the approximate age of certain objects that are 40,000 years old or younger.In the following section we are going to go more in-depth about carbon dating in order to help you get a better understanding of how it works.If the life of a radioactive substance is taken to mean the time that elapses before the activity drops to zero, then it is clear from the graph below that we would be waiting forever!A much more useful quantity for dealing with the life of radioactive substances is the half-life.As the activity of a sample is proportional to the number of radioactive nuclides present it is also possible to say that the half-life is the time taken for half of the radioactive nuclides in a sample to decay.We can also plot a graph of ln (that's small L and small N) N against t (Note ln N is the natural logarithm of N.Libby and coworkers, and it has provided a way to determine the ages of different materials in archeology, geology, geophysics, and other branches of science.Some examples of the types of material that radiocarbon can determine the ages of are wood, charcoal, marine and freshwater shell, bone and antler, and peat and organic-bearing sediments.

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Radiation counters are used to detect the electrons given off by decaying Carbon-14 as it turns into nitrogen.

Or Carbon-14 Dating is a useful example of the concept of half-life in practice.

Carbon-14 is a radioactive isotope of carbon with a half-life of 5730 years.

It is possible to compare the activity of a living sample of material with an ancient specimen (of the same mass) and estimate the age.

For example if a specimen has half the activity of a living sample of equal mass it is around 5730 years old i.e. If the activity were quarter it would be 2 x 5730 = 11460 years old i.e.