Scientific definition of radioactive dating
This method is not reliable for measuring the age of rocks less than 10 million years old because so little of the uranium will have decayed within that period of time.The Science Dictionary is the most comprehensive source of science definitions online with over 38K science terms written and created by our global team of scientists and academic professionals.Uranium-238, whose half-life is 4.5 billion years, transmutes into lead-206, a stable end-product.Boltwood explained that by studying a rock containing uranium-238, one can determine the age of the rock by measuring the remaining amount of uranium-238 and the relative amount of lead-206. The long half-life of uranium-238 makes it possible to date only the oldest rocks.
In 1907, the American chemist Bertram Boltwood demonstrated that he could determine the age of a rock containing uranium-238 and thereby proved to the scientific community that radioactive dating was a reliable method.(Whether they do or not is not what I'm addressing here.) I'm going to assume you are talking about methods to find out how old things are.There is radiometric dating, which figures out how old something is by the ratio of radioactive material present to its half-life product.So, if you know the radioactive isotope found in a substance and the isotope's half-life, you can calculate the age of the substance. Well, a simple explanation is that it is the time required for a quantity to fall to half of its starting value.So, you might say that the 'full-life' of a radioactive isotope ends when it has given off all of its radiation and reaches a point of being non-radioactive.
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.