Transcript Weathering
A.Two Types 1. Mechanical 2. Chemical B. Rates of Weathering Weathering PHYSICAL (Mechanical) Refers to breaking rocks into smaller pieces. Water and Ice Frost Wedging Frost Wedging Abrasion Abrasion Plant Wedging Plant Wedging Plant Wedging CHEMICAL Changing the minerals in a rock into softer, weaker minerals by chemical changes. CHEMICAL Changing the minerals in a rock into softer, weaker minerals by chemical changes. Hydration soften with water, makes clay minerals Carbonation Carbonic acid weathers rocks Carbonation Carbonic acid weathers rocks Carbonation Carbonic acid weathers rocks Oxidation Oxygen changes minerals. Fe + O = Rust Oxidation Oxygen changes minerals. Rates of Weathering How fast something weathers depends on: •surface area •composition of rock •the climate Surface Area 6 12 18 Resistance to Weathering Granite Limestone Resistance to Weathering A good example of climate affecting weathering is a granite obelisk called Cleopatra's Needle--for almost 3500 years it was in Egypt with barely a weathered trace but present in New York City for only about 80 years it has been weathered (pitted) a lot. Fastest weathering rate happens in warm and humid climates “In reaffirming the greatness of our nation, we understand that greatness is never a given. It must be earned. Our journey has never been one of shortcuts or settling for less. It has not been the path for the faint-hearted — for those who prefer leisure over work, or seek only the pleasures of riches and fame. Rather, it has been the risk-takers, the doers, the makers of things . . .” -Your President Venn Diagram Venn Diagram Rain Forest Desert •Thick Vegetation •Nocturnal Animals •High Humidity •Reptiles •Amazon •Ants •Less than 10 inches of rain •Camels •Sahara Venn Diagram Create a Venn diagram like the one above with three points in each section. Physical Weathering • • • Chemical Weathering • • • • • •