Carbon 14 is a radioactive isotope of carbon with six protons and eight neutrons. It is one of the three naturally occurring isotopes of carbon, along with carbon 12 and carbon 13. Carbon 14 is constantly produced in the Earth's atmosphere by the interaction of cosmic rays with nitrogen atoms.

The main difference between carbon 14 and regular carbon (carbon 12) is that carbon 14 is unstable and decays over time. This means that the amount of carbon 14 in an object decreases as time passes, which makes it a valuable tool for radiometric dating. The half-life of carbon 14 is 5,730 years, which means that it takes 5,730 years for half of the carbon 14 in an object to decay.

The decay of carbon 14 is also used in carbon-14 dating, a scientific technique that allows researchers to determine the age of an object up to about 50,000 to 60,000 years old. Carbon-14 dating is widely used in archaeology, paleontology, and other fields that study the age of ancient artifacts and fossils.

Carbon 14 is also used in medicine and other scientific fields. For example, it is used in medical imaging to help doctors diagnose and treat medical conditions. Carbon 14 is also used in tracer studies to track the movement of substances in the environment or in biological systems.