1. Today’s Agenda…Jan. 24th Bellringer: How do volcanoes form?
Share Homework
Weathering vs. Erosion
Notes on Weathering
BrainPop on Weathering
Homework

2. 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

3. Weathering
Science 6
Study Pack #6

4. Weathering
A process that breaks down rocks
Mechanical
Chemical

5. 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

6. 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

7. 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

8. Chemical Weathering
Occurs when the chemical composition of a rock changes
Causes are
Natural acids
Oxygen

9. Natural Acids
Carbonic acid (water and carbon dioxide) can dissolve certain rocks
Some plants produce acids that can affect rocks

10. Oxygen
When oxygen reacts with the iron in rocks it turns them orange or red

11. Assignment Frayer Model for Vocabulary Weathering
Definition – In your own words
Characteristics – You may want to include types here
Examples
Nonexamples