| Term | Definition |
|---|---|
| Fossils | Traces or remains of living things from long ago |
| Original remains | Fossils that are the actual bodies or body parts of organisms |
| Ice core | A tubular sample that shows the layers of snow and ice that built up over thousands of years |
| Relative age | Is the age of an event or object in relation to other events or objects |
| Index fossils | Fossils of organisms that were common, that lived in many areas, and that existed only during specific spans |
| absolute age | The actual age of an event or object |
| half-life | The length of time it takes half of the atoms in a sample of a radioactive element to change from an unstable form into another form |
| uniformitarianism | Huttons theory or that the earth is an always-changing place |
| Geologic time scale | divides the earths history into intervals of time defined by major events or changes on earth |
