Weathering and Erosion

Vocabulary 7.5 Weathering Mechanical weathering Ice wedging Chemical weathering Biological weathering 7.6 Erosion Deposition Valley Plains Delta Fiords

7.5 Weathering Breaks Down Rocks Weathering- slowly breaking down natural materials into smaller pieces

3 Kinds of Weathering Mechanical Weathering Physical forces Ice wedging Wind Water Glaciers

Chemical reactions with rocks Chemical weathering Chemical reactions with rocks CO2 (air)+ H2O (rain) H2CO3 (an acid) Acid dissolves limestone= caves Acid rain (pollution gas mixing with water in the air) = dissolved minerals Oxygen in air + water = rust

3. Biological weathering Living things that cause mechanical or chemical weathering Lichen = produces an acid Roots grown in cracks = split rocks

7.6 Erosion The movement of weathered rock from one place to another = erosion Fast or slow movement Big or small sizes Small to large distances When the material stops moving = deposition

Weathered rock can move by: Gravity (rock slide, avalanche)

2. Wind (particles in the wind, dust storm)

3. Water (rivers, streams)

Valley= V- shaped Plains = flat areas Delta= large triangle shaped area as a river enters a lake or ocean (sediment build up)

4. Ice (glaciers)

U shaped valleys, round bottoms, steep sides

Fiords Along the coast Long narrow inlets of the sea