1. Weathering 01/05/15 10-1 pgs. 246-250 IN: How is sediment/soil formed?

2.  Weathering - the breakdown of rock into smaller and smaller pieces. This is constantlyhappening!

3.  Mechanical  Chemical Types of Weathering

4.  Mechanical Weathering - the breakdown of rock by physical means. –Ice –Wind –Water –Gravity –Plants –Animals

5.  When water seeps into a crack in a rock and freezes it expands.  When it expands, it pushes against the sides of the crack, forcing it to open wider. Ice Wedging

6.  An enormous mass of moving ice. Glaciers

7. Glaciers Form when average temperatures are at or near freezing  Alpine glaciers create U-shaped valleys.  They push all the rock and sediment underneath them.

8. Rivers create V-Shaped valleys

9. Wind and Water

10.  Abrasion - the action of rocks and sediment grinding against each other and wearing away exposed surfaces. Wind and Water

11. Abrasion  When rocks grind against each other and wear away exposed surfaces.  Wind blows sand and dust against rocks.  Water in rivers and oceans cause rocks and sand to roll against each other.  Gravity causes rocks to fall

12.  Like ice wedging –Plants get into smaller cracks and as they grow they split the rock apart.

13.  Burrowing  Worms  Chemical Weathering

14.  Chemical Weathering - the chemical breakdown of rocks and minerals into new substances. –Water –Weak acids –Air –Soil

15.  Water causes many things to dissolve. –Even hard rock, like granite, is broken down by water.

16.  Acid rain is caused due to pollution.  Can cause very rapid weathering of rock.

17.  Breaks down limestone found underground –Forms caves

18.  Lichens produce organic acids that can slowly break down rock.

19.  Oxidation - a chemical reaction in which an element, such as iron, combines with oxygen to form an oxide.

20.  Water speeds up this process. –rust

21. Red Rock Canyon

22. OUT: Name three ways abrasion occurs in nature.