Which method is commonly used by scientists to determine the age of organic fossils?
A
X-ray diffraction
B
Infrared spectroscopy
C
Mass spectrometry
D
dating
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Carbon-14 dating is a method used to determine the age of organic fossils. It is based on the decay of the radioactive isotope Carbon-14 (C-14), which is present in all living organisms.
When an organism dies, it stops taking in Carbon-14, and the existing C-14 begins to decay at a known rate, called the half-life, which is approximately 5730 years.
Scientists measure the remaining amount of Carbon-14 in a fossil and compare it to the expected amount in a living organism to estimate the time since the organism's death.
The decay of Carbon-14 is a first-order reaction, and the age of the fossil can be calculated using the formula: \( t = \frac{\ln(\frac{N_0}{N})}{k} \), where \( N_0 \) is the initial quantity of C-14, \( N \) is the remaining quantity, and \( k \) is the decay constant.
Carbon-14 dating is effective for dating fossils up to about 50,000 years old, beyond which the remaining C-14 is too minimal to measure accurately.