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Today’s Agenda…Jan. 24 th. Bellringer: How do volcanoes form? Share Homework Weathering vs. Erosion Notes on Weathering BrainPop on Weathering Homework. BEFORE: Weathering or Erosion?. An old tombstone that is hard to read A mountain after a landslide Sand dunes
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Today’s Agenda…Jan. 24th • Bellringer: How do volcanoes form? • Share Homework • Weathering vs. Erosion • Notes on Weathering • BrainPop on Weathering • Homework
BEFORE: Weathering or Erosion? • An old tombstone that is hard to read • A mountain after a landslide • Sand dunes • Rocks broken into tiny pieces • A crack in a sidewalk • A ditch where water has once flowed
Weathering Science 6 Study Pack #6
Weathering • A process that breaks down rocks • Mechanical • Chemical
Mechanical Weathering • Breaks rocks into smaller pieces WITHOUT changing them chemically • Smaller pieces are identical to the original rock • Two causes are: • Ice (or Frost) Wedging • Plants and Animals
Ice Wedging • Water from rain or snow seeps into cracks in rocks • The water freezes and expands making the cracks open further until the rock breaks
Plants and Animals • Roots grow into cracks in rocks where water collects and force the rock apart • Some animals burrow through rocks and break them apart
Chemical Weathering • Occurs when the chemical composition of a rock changes • Causes are • Natural acids • Oxygen
Natural Acids • Carbonic acid (water and carbon dioxide) can dissolve certain rocks • Some plants produce acids that can affect rocks
Oxygen • When oxygen reacts with the iron in rocks it turns them orange or red
Assignment • Frayer Model for Vocabulary • Weathering • Definition – In your own words • Characteristics – You may want to include types here • Examples • Nonexamples