Weathering, Erosion, & Deposition – Sept. 22 and 23

1. Weathering, Erosion , & Deposition –SEPT. 22 AND 23The Wearing Down and Building Up of Earth

2. FALCON FOCUS- SEPT. 23 State 2 ways in which land can change over time when exposed to different elements.

3. ESSENTIAL QUESTION • What effects can weathering, erosion and deposition have on the Earth?

4. VOCABULARY QUIZ- use the correct word from the list …. • Earthquake • Lithosphere • Plate • Seismometer • Plate tectonics • Volcano • Triangulation • Focus • Epicenter

5. FALCON FOCUS – SEPT 22 Reflect on the quiz you took yesterday and answer the following questions: • What did I find most difficult? • Was it challenging? • What could I have done differently?

6. ESSENTIAL QUESTION- SEPT. 22 How might rain water, wind, and other natural occurrences affect the surface of the Earth?

7. WEATHERING, EROSION, & DEPOSITION • Performance Indicator: 8.E.5A.1 Develop and use models to explain how the process of weathering, erosion, and deposition change surface features in the environment.

8. PEER/PAIR GROUP WORK- Sept. 22 In pairs, carry out the Erosion Cookie Experiment. Please ensure that you follow the instructions carefully.

9. WEATHERING • Weathering is any process that breaks down rocks and creates sediments. • There are two forms of weathering, chemical and mechanical (physical).

10. CHEMICAL WEATHERING • Chemical weathering is decomposition of rock caused by chemical reactions resulting in formation of new compounds.

11. EXAMPLES OF CHEMICAL WEATHERING • the process that breaks down rock through chemical changes. • The agents of chemical weathering: • water- water dissolves rock over time • oxygen- combines with iron to form rust (oxidation) • carbon dioxide- dissolves in water to form carbonic acid • living organisms- plant roots secrete acids • acid rain- from the burning of fossil fuels

12. Water • Water weathers rock by dissolving it.

13. Oxygen • Iron combines with oxygen in the presence of water in a processes called oxidation. • The product of oxidation is rust.

14. Carbon Dioxide • CO2 dissolves in rain water and creates carbonic acid. • Carbonic acid easily weathers limestone and marble.

15. Living Organisms • Lichens that grow on rocks produce weak acids that chemically weather rock.

16. Acid Rain • Compounds from burning coal, oil and gas react chemically with water forming acids. • Acid rain causes very rapid chemical weathering.

17. 2 factors that determine the rate of weathering: • rock type- Rock that is permeable (has holes that let water in), weathers faster than rock that is impermeable. The mineral content of rock also determines how fast a rock weathers. • climate- Rock weathers faster in warm, humid climates.

18. MECHANICAL WEATHERING • Mechanical (physical) weathering is the breakdown of rock into smaller pieces.

19. Mechanical Weathering • Process by which rocks are broken down into smaller pieces by physical forces. • Types of Mechanical weathering • Ice wedging • Plant roots • Abrasion • Burrowing of animals (animal action) • Temperature changes (freezing and thawing)

20. ICE (Frost) Wedging

21. Plant Roots

22. ABRASION • mechanically weathered by abrasion. • Abrasion is weathering by grinding action.

23. These mountains in Salt Lake City, Utah, were also weathered by abrasion.

24. Abrasion

25. Animal Action (Burrowing)

26. How decomposers enrich soil and make it fertile: mechanical weathering. Chipmunks live in dens in the soil and search the litter for seeds and nuts. Plant roots break up the soil and hold it in place. Earthworms break up the soil, making it easier for plant roots to spread and for air and water to enter the soil. They create waste which makes soil more fertile by adding nitrogen. Bacteria are decomposers that break down animal and plant remains and wastes.

27. Freezing and Thawing(temperature changes)

28. Erosion • Erosion is the removal of rock particles from a location. • Caused by water, wind, ice, or gravity.

29. EROSION • Erosion is the process by which natural forces move weathered rock and soil from one place to another. Gravity, running water, glaciers, waves, and wind all cause erosion. The material moved by erosion is sediment.

30. GRAND CANYON, ARIZONA

35. WATER EROSION Water sources such as rivers, streams, ocean tides, and runoff can move rock particles away....

36. Water Erosion-Rivers • Rivers and streams carry sediment. As the sediment moves mechanical weathering occurs. • Through water erosion, rivers create waterfalls, flood plains, and valleys.

40. Water Erosion-Waves • Waves- waves shape the coasts by transporting sand. While the sand is moved, mechanical weathering occurs. • Waves create sea stacks, caves, arch, and wave-cut cliffs.

41. Erosion by Runoff • As water from precipitation (rain, snow, etc.) moves over the land, it carries particles with it. The moving water is called runoff. • Runoff creates rills and gullies.

42. WIND EROSION Sometimes the wind can move rock particles away: this can lead to dust storms!

43. WIND EROSION • Wind Erosion creates dust storms, hoodoos, and arches.

44. Ice Erosion As a glacier flows over the land, it picks up rocks in a process called plucking.

45. Ice Erosion Ice erosion creates: U-shaped valleys, glacial lakes, moraines, drumlins, and kettle lakes.

46. Ice Erosion Ice erosion creates: U-shaped valleys, glacial lakes, moraines, drumlins, and kettle lakes.

47. Think about it…. • Water is NEEDED by all living things to survive. • How does water change the planet?

48. Erosion by Gravity • Gravity causes sediment to move downhill. • It creates: landslides, mudflows, and creeps.

49. DEPOSITION • Deposition occurs when the agents (wind or water) of erosion lay down sediment.  Deposition changes the shape of the land.

50. Deposition Deposition is the adding of sediment in an area as it settles out and forms new landforms. In this picture, taken in Squaw Creek, near Sisters, Oregon, rocks have been deposited along the bank of the river after heavy rains.