What are the scientific principles that allow archaeologists to date charcoal, bone, or other organic materials that they find in archaeological contexts?
"Carbon dating" is one of several dating techniques that use our understanding of radioactivity. A radioactive element is one that periodically emits electrons into the environment, a process called decay.
The element carbon exists in several atomic variants (called isotopes), the most common of which comes with 12 electrons (12C, referred to as carbon 12), while the least common has 14 electrons and is radioactive (14C, also know as carbon 14 or radiocarbon). We know the relative abundance of 14C to 12C in nature. We also know that 14C's decay rate is constant, and what that rate is. In any sample of pure carbon exactly half of the 14C atoms will decay in 5,730 years (this is known as radiocarbon's half-life). ...