Weathering and Erosion: Exploring Rocks and Agents of Change

1. Today I am collecting your labs and weathering graph practice Homework • Kickstart • Write and Answer the following questions in your notebooks: • How do you think rocks break apart? • 2. Analyze the picture. What is happening to the cement? Explain your answer.

2. Learning Outcome: I can explain how erosion and weathering occurs by using specific vocabulary when applying real-world scenarios.

3. 1 Weathering • Weathering is a mechanical or chemical surface process that breaks rocks into smaller pieces. • Mechanical • Chemical

4. 1 Mechanical Weathering • Mechanical weathering breaks rocks into smaller pieces without changing them chemically. • The small pieces are identical in composition to the original rock. • Two of the many causes of mechanical weathering are • ice wedging and • living organisms.

5. 1 Ice Wedging • Water seeps into cracks. • The deeper the cracks are, the deeper water can seep in. • The water freezes and expands, forcing the cracks to open further.

6. 1 Ice Wedging • The ice melts. • If the temperature falls below freezing again, the process will repeat itself.

7. 1 Plants and Animals • Plant roots grow deep into cracks in rock where water collects. • As they grow, roots become thicker and longer, slowly exerting pressure and wedging rock apart.

8. Learning Target: I can explain how deposition, erosion and weathering occurs by using specific vocabulary when applying real-world scenarios. 1 Plants and Animals • Gophers and prairie dogs also weather rock—as do other animals that burrow in the ground. • As they burrow through sediment or soft sedimentary rock, animals break rock apart.

9. Answer the following: 1. Which of the following is an example of chemical weathering? Plant roots grow in cracks in rock and break the rock apart? Freezing and thawing of water widens cracks in rocks Wind blows sand into rock, scratching the rock. Oxygen causes iron- bearing minerals in rock to break down.

10. 1 Chemical Weathering • Chemical weathering occurs when the chemical composition of rock changes. • This kind of weathering is rapid in tropical regions where it's moist and warm most of the time.

11. In your notebook, write and answer the following question. 1 Explain how a tree can break apart rock. Answer As the tree grows, its roots become thicker and longer. The roots exert pressure on the rocks eventually breaking them apart.

12. 1 Chemical Weathering • The table summarizes the rates of chemical weathering for different climates.

13. Natural Acids 1 • Some rocks react chemically with natural acids in the environment. • When water mixes with carbon dioxide in air or soil, for example, carbonic acids forms. • Although carbonic acid is weak, it reacts chemically with many rocks. • When carbonic acid comes in contact with rocks like limestone, dolomite, and marble, they dissolve.

14. 1 Plant Acids • Many plants produce a substance called tannin. • In solution, tannin forms tannic acid. • This acid dissolves some minerals in rocks. • Moss growing on rocks can cause chemical weathering.

15. 1 Effect of Oxygen • Oxidation is the effect of chemical changes caused by oxygen. • When iron-containing materials such as steel are oxidized, a chemical reaction causes the material to rust.

16. 1 Effect of Oxygen • When some iron-containing minerals are exposed to oxygen, they can weather to minerals that are like rust. • This leaves the rock weakened, and it can break apart.

17. Erosion

18. Kickstart:Line up around the classroom. Backs against the wallsWhen you sit.Take out your labs.Take out your notebook Answer the following: Describe the process of erosion.

19. 2 Start - Which of the following is NOT an agent that carries erosion products? • Wind • Glaciers • Gravity • Water https://www.youtube.com/watch?v=ZNJe6hrdL3M

20. Learning Outcome: I can explain how natural phenomena change the surface of Earth by identifying the agents of erosion.

21. Erosion Erosion: the wearing away and removal of rock or sediment. Erosion occurs because gravity, ice, water and wind sculpt Earth’s surface.

22. 2 Agents of Erosion • Erosion is the wearing away and removal of rock or sediment. • Erosion occurs because… • gravity, • ice, • wind, • water

23. 2 Gravity • Gravity pulls everything on Earth toward its center. • When gravity alone causes rock or sediment to move down a slope, the erosion is called mass movement. • Mass movements can occur anywhere there are hills or mountains. https://www.youtube.com/watch?v=ZefK3EVo09Q

24. Erosion of Earth’s Surface 2 Ice • When the ice in a glacier becomes thick enough, its own weight causes it to flow downhill under the influence of gravity. • Glaciers move over Earth's surface, they erode materials from some areas and deposit sediment in other areas.

25. Erosion of Earth’s Surface 2 Wind • When wind blows across loose sediments like silt and sand, it lifts and carries it. • Wind often leaves behind particles too heavy to move. • This erosion of the land by wind is called deflation.

26. Erosion of Earth’s Surface 2 Wind • Abrasion is a form of erosion that can make pits in rocks and produce smooth, polished surfaces. • Abrasion is common in some deserts and in some cold regions with strong winds.

27. Erosion of Earth’s Surface 2 Water • Water that flows over Earth's surface is called runoff. • Runoff is an important agent of erosion. • The more speed water has, the more material it can carry with it.

28. Shaping Earth’s Surface • Over long periods of time, water moving in a stream can have enough power to cut large canyons into solid rock. • Many streams together can sculpt the land over a wide region, forming valleys and leaving some rock as hills. https://www.youtube.com/watch?v=ZNJe6hrdL3M

29. 2 Which of the following is NOT an agent that carries erosion products? • Wind • Glaciers • Gravity • Water https://www.youtube.com/watch?v=ZNJe6hrdL3M

30. Task: You have 16 different scenarios, Create a table on the chart paper provided. In pairs, place the scenarios where best fits. Copy the chart in your notes and choose one example from each category to write in your notebook. Learning Target: I can explain how deposition, erosion and weathering occurs by using specific vocabulary when applying real-world scenarios.

31. What is soil? How is it made?

32. Kickstart: Answer the following questions in your notebooks: When a tree breaks through the cement. This process is called ______________ __________________. The process in which rocks break Apart is called _______________.

33. Learning Outcome: I can explain how soil is formed by determining the difference between organic material and weathered rock.

34. Chemical Weathering 1 • The table summarizes the rates of chemical weathering for different climates. • Identify the independent and dependent variable.

35. 1 Soil • Soil is a mixture of weathered rock, organic matter, water, and airthat supports the growth plant life. • Organic matter includes decomposed leaves, twigs, roots, and other material.

36. 1 Climate • Climate affects the amount of organic material in soil. • Why does soils in desert climates contain little organic material? • However, in warm, humid climates, vegetation is lush and much organic material is present.

37. Weathering and Soil Formation 1 Climate • The result is the formation of a dark-colored material called humus. • Most of the organic matter in soil is humus. • Humus helps soil hold water and provides nutrients that plants need to grow.

38. Weathering and Soil Formation 1 Time • It can take thousands of years for some soil to form. • As soils develop, they become less like the rock from which they formed. • Thicker, well-developed soils often are found in areas where weathering has gone on undisturbed for a long period of time.

39. Weathering and Soil Formation 1 Organisms • Organisms influence soil development. • Lichens can grow directly on rock. • As they grow, they take nutrients from the rock that they are starting to break down, forming a thin soil.

40. Weathering and Soil Formation 1 Organisms • After a soil has formed, many types of plants such as grasses and trees can grow. • The roots of these plants further break down the parent rock.

41. Weathering and Soil Formation 1 Organisms • Dead plant material such as leaves accumulates and adds organic matter to the soil.

42. Write and answer the following question in your notebook. How is a rusty nail an example of chemical weathering? Answer When iron-containing materials, such as a nail, are exposed to oxygen, a chemical reaction occurs and rust is produced. The rust has a different chemical composition than the nail.

43. https://ny.pbslearningmedia.org/resource/nat08.earth.geol.eros.erosion/nature-water-erosion/#.WNG9T4WcEhlhttps://ny.pbslearningmedia.org/resource/nat08.earth.geol.eros.erosion/nature-water-erosion/#.WNG9T4WcEhl

44. Shaping Earth’s Surface • When rivers enter oceans or lakes, the water slows and sediment is deposited. • This can form large accumulations of sediment called deltas.

45. Weathering and Soil Formation 1 Parent Rock • One factor affecting soil formation is the kind of parent rock that is being weather. • For example, in areas where sandstone is weathered, sandy soil forms.

46. Weathering and Soil Formation 1 The Slope of the Land • The topography, or surface features, of an area also influence the types of soil that develop. • On steep hillsides, soil has little chance of developing. • This is because rock fragments move downhill constantly.

47. Section Check 1 Which of the following does NOT affect soil formation? A. climate B. carbonic acid C. organisms D. topography

48. Section Check 1 Answer The answer is B. Many factors affect soil formation. Carbonic acid is responsible for changing the chemical composition of minerals in rock.

49. Section Check 2 Question 1 Compare and contrast continental glaciers and valley glaciers.

50. Section Check 2 Answer Continental glaciers are located in Polar Regions and are very large and thick. Valley glaciers are much smaller and are found high up in the mountains where the average temperature is not warm enough to melt the ice. Glaciers can erode rock by pulling out pieces of rock underneath them and dragging them along the surface as the glacier moves.