Defining Nuclear Decay
Nuclear decay, also known as radioactivity, is the process by which an unstable atomic nucleus spontaneously loses energy by emitting radiation. This transformation results in the formation of a different, more stable nucleus. The emitted radiation can take various forms, such as alpha particles, beta particles, or gamma rays, each changing the parent nucleus in a specific way.
Understanding Half-Life
Half-life (t½) is a fundamental characteristic of a radioactive isotope, defined as the time it takes for half of the radioactive atoms in a sample to decay. It is a statistical measure; while individual decay events are random, for a large number of atoms, the half-life is constant and predictable. After one half-life, half of the original radioactive material remains; after two half-lives, one-quarter remains, and so on.
A Practical Example of Half-Life
Consider Carbon-14, which has a half-life of approximately 5,730 years. If you start with a 100-gram sample of Carbon-14, after 5,730 years, 50 grams of Carbon-14 will remain, with the other 50 grams having decayed into Nitrogen-14. After another 5,730 years (a total of 11,460 years), only 25 grams of Carbon-14 will be left.
Importance and Applications
Nuclear decay and half-life are crucial concepts with widespread applications. They form the basis of radiometric dating, used to determine the age of ancient artifacts, fossils, and geological formations (e.g., carbon-14 dating). In medicine, radioactive isotopes with specific half-lives are used for diagnostic imaging (e.g., PET scans) and targeted radiation therapy for cancer. Furthermore, understanding decay processes is vital for nuclear power generation and safely managing radioactive waste.