1. Carbon dating is the method used to calculate the age of rocks, minerals or fossils. 

2. The breakdown of radioactive isotopes of certain elements such as carbon, uranium and potassium takes place at a known rate. So the age of rock or mineral containing isotopes can be calculated. 

3. Archaeologists use the exponential, radioactive decay of carbon 14 to estimate the death dates of organic material. 

4. The earth’s atmosphere contains various isotopes of carbon, roughly in constant proportions. 

5. These include the main stable isotope¹²C and an unstable isotope¹⁴C. 

6. Through photosynthesis, plants absorb both forms from carbon dioxide in the atmosphere.

7. When an organism dies, it contains the standard ratio of ¹⁴C to ¹²C. 

8. But as the ¹⁴C decays with no possibility of replenishment, the proportion of carbon 14 decreases at a known constant rate. 

9. The time taken for it to reduce by half is known as the half-life of ¹⁴C, which is 5730. 

10. The measurement of the remaining proportion of ¹⁴C in organic matter thus an estimation of its age. 

11. As the half life of carbon – 14 is 5,700 years, it is useful for dating objects up (o about 60,000 years old.