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C1 Review. Ms. Leung. Changing of the Earth’s surface by breaking it down. 2 processes- WEATHERING- the breaking down of the materials of Earth’s crust into smaller pieces. EROSION- the picking up and carrying away the pieces. 2 types of weathering. Physical Weathering Chemical Weathering.
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C1 Review Ms. Leung
Changing of the Earth’s surface by breaking it down • 2 processes- • WEATHERING- the breaking down of the materials of Earth’s crust into smaller pieces. • EROSION- the picking up and carrying away the pieces.
2 types of weathering • Physical Weathering • Chemical Weathering
Physical Weathering- WATER • Weathering happens when the crust is exposed to water, air, and changes in temperature. • Water - water can dissolve minerals right out of the crust. - Moving water can make pieces of rock bang into each other. - Small chips can break off the surface of the rock- this causes the rock to get smaller and rounder. - The churning (harsh movement) of water streams can wear down big pieces of rock into small round pebbles.
Physical weathering- Wind • Wind (moving air) • Blows sand and other broken bits of rock over the Earth’s surface (This can also wear away rock)
Physical weathering- Temperature • Temperature drops low enough for water to freeze- when the water freezes is expands- gets bigger- take up more spaces. When water freezing in cracks of rocks the force of the expanding water is great enough to split the rock apart. • Change in temperature can also cause a rock to expand and contract. (only certain types of rocks) This will eventually cause the rock to break down.
Chemical Weathering • Air contains gases that react chemically to form new substances. -Oxygen in the air reacts with iron to form rust - Carbon Dioxide and Sulfur Dioxide in the air react with rain to form acids (eat away limestone rock)
Erosion • Carrying away of pieces of weather rock by gravity • Think about it over enough time, erosion can carry away a boulder, a hill, or even a mountain. • The most important factor of erosion is WATER.
The most important factor of erosion is WATER. • From the moment a drop of water hits the ground, it erodes the land. • Once water reaches the ground, it will begin to move downhill. • The water moving down hill will pick up things and carry them along in its journey. • The faster the water is moving, the bigger the piece of rocks it can move.
Wind and ICE Erosion • Wind- picks up small particles and moves them • ICE- freezes onto the rock and scrapes away the surfaces. Ice can also tear rocks from the ground as it moves.
Let’s think about what happens to moving water • It is eventually going to slow down when it flows into a large body of water (OCEAN or lake) • When the water stops moving it also stops carrying the eroded material- these pieces are just dropped. The dropped pieces of eroded material is called deposition. • Deposition-The dropping off of bits of eroded rock.