| A | B |
|---|
| fossils | impressions and remains of organisms |
| fossil record | information about changes of life from fossils |
| geologic time scale | time line of changes on Earth |
| fossils form when | organisms are buried in mud or quicksand |
| why are not fossils in igneous rocks? | because fossils burn in magma |
| weathering | process that breaks rocks into smaller pieces |
| what breaks rocks? | temperature, wind, rain, snow |
| three kinds of weathering | mechanical, chemical, biological |
| mechanical weathering | caused by physical forces |
| examples of mechanical weathering | ice when expands breaks the rocks |
| Other example on mech. weathering | wind rubs the surface of rocks |
| chemical weathering | caused by chemical reactions |
| examples of chemical weathering | caused by carbon dioxide or acids |
| biological weathering | caused by living things like plants |
| erosion | movement of weathered rocks |
| deposition | laying down of sediments |
| how weathered rock move? | due to gravity, wind, water and ice |
| caused by gravity | landslides and avalanches |
| caused by wind | dust storms |
| caused by water | rivers carry sediments |
| caused by ice | weight of ice causes glaciers to move downhill |
| rock cycle | change from one type of rock to another |
| from igneous to sedimentary | igneous rock breaks and deposits as sediment |
| sedimentary to metamorphic | by heat and pressure changes to metamorphic rock |
| metamorphic to igneous | metamorphic rock melts into magma and then cools |
