Unit 8 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity Copyright © Houghton Mifflin Harcourt Publishing Company 1

Unit 8 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity Florida Benchmarks SC.6.N.3.4 Identify the role of models in the context of sixth grade science benchmarks. SC.6.E.6.1 Describe and give examples of ways in which Earth’s surface is built up and torn down by physical and chemical weathering, erosion, and deposition. SC.6.E.6.2 Recognize that there are a variety of different landforms on Earth’s surface such as coastlines, dunes, rivers, mountains, glaciers, deltas, and lakes and relate these landforms as they apply to Florida. Copyright © Houghton Mifflin Harcourt Publishing Company 2

Unit 8 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity While taking notes, keep in mind our learning goal for 8.3!

How can wind shape Earth? Unit 8 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity How can wind shape Earth? When wind moves soil, sand, and rock particles, it acts as an agent of erosion. The grinding and wearing down of rock surfaces by other rock or sand particles is abrasion. Rocks can become smooth and polished from abrasion. Copyright © Houghton Mifflin Harcourt Publishing Company 4

How can wind shape Earth? Unit 8 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity How can wind shape Earth? The removal of fine sediment by wind is called deflation. Desert pavement results when wind carries soil and fine sediment away from an area, leaving only rocks behind. Copyright © Houghton Mifflin Harcourt Publishing Company 5

How can wind shape Earth? Unit 8 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity How can wind shape Earth? Dunes are mounds of wind-deposited sand common in deserts and along the shores of lakes and oceans. Dunes usually move in the same direction the wind is blowing. White sand dunes of Thailand Wind is responsible for the formations of sand dunes. Copyright © Houghton Mifflin Harcourt Publishing Company 6

Blowing sand grains would move faster than bouncing sand grains.

How can wind shape Earth? Unit 8 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity How can wind shape Earth? Loess are thick deposits of windblown, fine-grained sediment. The fine-grained material in loess can be carried far away from the original source and is a valuable resource for forming good soils. Copyright © Houghton Mifflin Harcourt Publishing Company 8

What kinds of ice shape Earth? Unit 8 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity What kinds of ice shape Earth? A glacier is a large mass of moving ice that forms by the compacting of snow by natural forces. A glacier is formed when snow builds up, and its weight compresses the snow below into ice. Glaciers move downhill by gravity and cause erosion. As a glacier melts, it deposits the materials it carries. Glacial drift is the general term for all materials carried and deposited by a glacier. Copyright © Houghton Mifflin Harcourt Publishing Company 9

In order for this landform, glacier, to form it must be cold and more snow falls than melts.

How can gravity shape Earth? Unit 8 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity How can gravity shape Earth? Gravity influences the movement of water and ice. Gravity also moves rocks and soils down slope. Mass movement is the shifting of materials due to gravity. QUESTIONS???? What were the two types of mass movement called? Which one was more dangerous? Copyright © Houghton Mifflin Harcourt Publishing Company 11

Creep is the extremely slow movement of materials down slope.

How can gravity shape Earth? Unit 8 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity How can gravity shape Earth? Rapid mass movements usually happen on steep slopes and are the most destructive. A rockfall happens when loose rocks fall down a steep slope. A landslide is the sudden and rapid movement of a large amount of material down slope. Copyright © Houghton Mifflin Harcourt Publishing Company 13

How can gravity shape Earth? Unit 8 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity How can gravity shape Earth? A mudflow is a rapid movement of a large mass of mud. Mudflows happen when a large amount of water mixes with soil and rock. A sparsely vegetated mountainside is most likely where a mudflow will happen. Fairy Stream 14

Unit 8 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity How can gravity shape Earth? Deforestation, volcanic eruptions, and heavy rains can all create mudflows.

So back to our learning goal… How do wind, ice, and gravity change Earth’s surface?

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