Once an organism is decoupled from these cycles (i.e., death), then the carbon-14 decays until essentially gone.The half-life of a radioactive isotope (usually denoted by $$t_$$) is a more familiar concept than $$k$$ for radioactivity, so although Equation $$\ref$$ is expressed in terms of $$k$$, it is more usual to quote the value of $$t_$$.What methods do they use and how do these methods work?In this article, we will examine the methods by which scientists use radioactivity to determine the age of objects, most notably carbon-14 dating.All organisms have a certain amount of 14C present in their bodies – it is absorbed out of the atmosphere by plants during the process of photosynthesis, and transferred to animals when the plants are eaten.While alive, organisms experience a balance of 14C intake and dissipation.Carbon 14 is continually being created in the Earth's atmosphere by the interaction of nitrogen and gamma rays from outer space.Since atmospheric carbon 14 arises at about the same rate that the atom decays, the Earth's levels of carbon 14 have remained constant.