2-WRITE AT LEAST TWO FULLSENTENCES- Do Now For Monday, Jan. 7th 2013-WRITE AT LEAST TWO FULLSENTENCES-Use your memory and your common knowledge to describe the difference between weathering and erosion
3GUIDED NOTES FOR 7 -1 ROCKS AND WEATHERING Weathering – The process that breaks down rock and other substances at Earth’s surface.Heat, cold, water and ice – CO2, & O2 contribute to weathering.Ontario, CA
4Erosion is the MOVEMENT of rock particles by wind, water ice or gravity. Erosion is the process that wears away surface materials and moves them from one place to another.
5Five types of mechanical weathering: Mechanical Weathering – The process that breaks rock into smaller pieces while the rock’s composition remains the same.Five types of mechanical weathering:Freezing and thawing – (Ice wedging)Release of pressurePlant growthAbrasionAnimal action
6Ice Wedging is the freezing and thawing of water in cracks in rock
7Release of pressure happens when erosion below rock causes it to crack and flake off. Ontario, CA
8Another example of pressure release is a famous 8,800 ft. mtn Another example of pressure release is a famous 8,800 ft. mtn. in Yosemite National Park. (Half Dome)
9Plant Growth refers to tree and other plant roots prying apart cracked rocks as they grow.
10Abrasion happens when sand and rock particles scrape and wear away rock surfaces like sandpaper on wood.(Ohio)
11Animal action loosens and breaks apart rocks in the soil. *
12Chemical Weathering!The process that breaks down rock through chemical changes.Chemical weathering alters (changes) the composition of the rock.As chemical weathering occurs, the new rocks are made up of different minerals than before.Many times, mechanical weathering breaks rock into smaller pieces creating greater surface area for easier chemical weathering.
13Four Types of Chemical Weathering! Water or HydrolysisOxidationCarbonic Acid or CarbonationPlant roots
14Water or Hydrolysis –Water dissolves certain types of rock.
16Oxidation – O2 in the air plus iron in the rock may cause rust, which weakens the rock’s structure.
17Carbonic Acid or Carbonation – CO2 in the air and rainwater combine to produce a weak acid (acid rain) that dissolves some types of rock.
18Plant Growth – Trees, plants and lichen produce weak acids that dissolve the rock they touch.
19Rate of Weathering is affected by two factors! Type of Rock: Rocks that are more permeable weather faster. Permeable rock has tiny air spaces that allow water to seep in.Climate: In hot and wet climates, rock weathers faster.