| A | B |
|---|
| geology | studying the history of the Earth |
| Geologic time scale | the Earth's history,written in years and put onto a scale |
| era | a division of geologic time |
| Big Bang Theory | suggests that all the matter ( anything that has weight and takes up space)and space were once concentrated in a single great dense glowing mass. The mass exploded into billions of galaxies that are moving away from each other. |
| Theory | what you think may have happened based on facts |
| Law | something that happens based on scientific facts |
| Pangaea | all the continents on earth were once one giant land mass. Pangaea is the name given to this land mass. It broke apart in the Palezoic (200 mya) era |
| fossils | imprints of former living creatures in the Earth's crust |
| index fossils | species that are wide spread & short living |
| trilobites | extinct Palezoic Era ocean creatures |
| ammonite | a type of creature with a spirial shell that lived mostly in the Mezozoic Era |
| extinct | animals that are no longer living |
| relative dating | arrange events in order |
| radiometric dating | a technique that uses radioactivity to find the approximate age of certain rocks |
| half-life | the time required for half the atoms of a radioactive substance to break apart |
| radioactive element | an element whose atoms change naturally to form new atoms. The rate of chnage stays the same. |
