Argon radioactive dating
Because plants use carbon dioxide for photosynthesis, this isotope ends up inside the plant, and because animals eat plants, they get some as well.When a plant or an animal dies, it stops taking in carbon-14.With rubidium-strontium dating, we see that rubidium-87 decays into strontium-87 with a half-life of 50 billion years.By anyone's standards, 50 billion years is a long time.
This provides a built-in cross-check to more accurately determine the age of the sample.The methods work because radioactive elements are unstable, and they are always trying to move to a more stable state. This process by which an unstable atomic nucleus loses energy by releasing radiation is called radioactive decay.The thing that makes this decay process so valuable for determining the age of an object is that each radioactive isotope decays at its own fixed rate, which is expressed in terms of its half-life.When the isotope is halfway to that point, it has reached its half-life.
There are different methods of radiometric dating that will vary due to the type of material that is being dated.These two uranium isotopes decay at different rates. The half-life of the uranium-238 to lead-206 is 4.47 billion years.