| A | B |
|---|
| radioactive decay | the process in which an unstable atom tends to break down into a stable atom of another element |
| radioactive dating | A technique used to determine the actual age of a fossil on the basis of the amount of a radioactive element it contains |
| absolute dating | A technique used to determine the actual age of a fossil - also known as radioactive dating |
| relative dating | A technique used to determine the age of a fossil by comparing its placement with that of fossils in other layers of rock - also known as the law of superposition |
| Law of Superposition | states that younger layers of rock are deposited on top of older layers |
| half-life | length of time required for half of the radioactive atoms in a sample to decay |
| Isotopes | Atoms of the same element that have different numbers of neutrons |
| parent element | the original element before radioactive decay |
| daughter element | the new element that results from the radioactive decay of the parent element |
| Atom | Smallest particle of an element |
