1. How do weathering & erosion work together to change the shape of Earth’s surface?

2. Erosion The movement of rock particles by wind, water, ice, or gravity

3. Weathering The process that breaks down rock & other substances on Earth’s surface

4. 2 types of weathering: Mechanical Chemical

5. Mechanical Weathering Rock is physically broken into smaller pieces By the process of: –Freezing & thawing –Release of pressure –Growth of plants –Actions of animals –Abrasion

6. Mechanical weathering can wear away more than whole rock…

7. New mechanical weathering terms: Abrasion: grinding away of rock by rock particles carried by water, ice, wind, or gravity Ice wedging: wedges of ice in rocks widen & deepen cracks

8. Chemical Weathering Breaks rocks down through chemical changes By the process of: –Water –Oxygen –CO2 –Living organisms –Acid Rain

9. Water… The most important chemical agent Water weathers rock by dissolving it

10. How does water assist in weathering & erosion? Runoff: all the remaining water that moves over Earth’s surface –It picks up soil particles as it moves across the land

11. Rills Tiny grooves in the soil caused from runoff

12. Gullies Large grooves, or channel, in the soil the carries runoff after a storm They flow only after it rains

13. Stream Channel in which water flows in constantly

14. Tributary A stream that flows into a larger stream

15. River A large stream Rivers erosion creates: – valleys – waterfalls –flood plain –meanders –oxbow lakes

16. Valley

17. Waterfalls

18. Flood Plain Flat, wide area of land that runs along side a river

19. Meander Looplike bend in the course of a river

20. Oxbow Lake A meander that has been cut off from the river

21. River Deposits Water moves sediments & rocks with it depositing them elsewhere River deposits create landforms like: –Alluvial fans –Deltas –Soil on a flood plains

22. Alluvial Fan Wide, sloping deposit of sediment formed where a stream leaves a mountain range

23. Delta Sediment deposited where a river flows into an ocean Can be shaped like an arc, triangular, bird’s foot

24. How do sediments enter rivers & streams? Most washes or falls into the river as a result of mass movement or runoff Other sediments erode from the bottom or sides of the river

25. Abrasion Wearing away of rock by a grinding action Boulders become smaller and smaller as they move down a streambed

26. How much sediment can a river carry? A load! Load: the amount of sediment that a river carries

27. Groundwater can create erosion too! Groundwater: underground water Stalactite: a calcite deposit that hangs like an icicle from the roof of a cave Stalagmite: cone shaped calcite deposit growing up from the cave floor

28. What does the amount of runoff depend on? 5 factors determine the amount of runoff an area receives: –Amount of rainfall –Vegetation –Type of soil –Shape of land –How people use land

29. How does ice change the shape of the land? Glaciers: large mass of ice that moves slowly over land 2 kinds: –Valley –continental

30. Valley Glacier Long, narrow glacier that forms when snow & ice build up high in a mountain valley

31. Continental Glaciers Glacier that covers much of a continent or island Much larger than valley glaciers They cover @ 10% of Earth

32. How do glaciers form? They form in areas where more snow falls than melts Snow builds up over time The pressure compacts the snow into ice

33. How do glaciers move? Gravity! Valley glaciers flow a few cm-a few meters each day Continental glaciers flow in all directions

34. How do glaciers change the land? Glaciers erode the land through 2 processes called plucking & abrasion

35. Plucking When a glacier flows over land, it picks up rocks in the process Rock fragments freeze to the bottom of the glacier

36. Abrasion As the glacier drags the rocks across the land it gouges & scratches the bedrock

37. What is glacial deposition? When the glacier melts, it deposits the sediment it eroded from the land creating various landforms –Moraine –Prairie pothole –Kettle Lake

38. Moraine A ridge formed by the till deposited at the edge of a glacier

39. Kettle A small depression that forms when a chunk of ice is left in glacial till

40. Wave Erosion

41. Wind Erosion

42. How does gravity assist in weathering & erosion? Gravity: a force that moves rocks & other materials downhill Gravity causes mass movement Mass Movement: any type of process that moves sediment downhill –Ex: landslides, slump, mudflows, creep

43. Landslides Most destructive kind Occurs when rock & soil slide quickly down a steep slope Caused by earthquakes, roadwork

44. Slump A mass of rock& soil that suddenly slips down a slope

45. Mudflows Rapid, downhill movement of a mixture of water, rock, & soil Amount of water can be as much as 60% Can occur during heavy rains or earthquakes

46. Creep Very slow downhill movement of rock & soil It’s barely noticeable It can tilt telephone poles, fenceposts, or gravestones in weird ways

47. At what rate does rock weather? Depends on type of rock & climate

48. Type of rock Permeable: material is full of tiny, connected air space that allow water to seep through it

49. Climate Average weather conditions in an area Chemical & Mechanical weathering occurs faster in wet climates Chemical reactions occur faster in higher temperatures

50. What is soil? Soil is loose, weathered material on Earth’s surface

51. How does soil form? It forms when rock that is broken down by weathering mixes with other materials on the surface Soil is constantly formed where bedrock (layer of rock beneath the dirt) is exposed

52. What’s in the soil? Soil is a mixture of rock particles, minerals, dead stuff, air, & water Type of rock depends on bedrock & weathering Humus: dark substance that forms as plant & animal remains decay

53. How does the soil feel? Sand is gritty while clay is smooth Texture depends on size of individual soil particles Texture is important for plant growth Largest to smallest: –Gravel –Sand –Silt –Clay

54. Loam Soil made of equal parts of clay, sand, & silt Holds both water & air Best for growing most types of plants

55. What is a soil horizon? Layer of soil that differs in color & texture from the layers above or below it Soil is divided into 4 horizons: –Horizon A-Topsoil: dark brown, crumbly layer –Horizon B-Subsoil: clay, little humus, particles –Horizon C-Parent Material: partly weathered rock –Horizon D-Bedrock: large pieces of rock`

57. What lives in the soil? Organisms make space in the soil for air & water –Ex: mice, ants, snails, beetles, worms, lots of plants

58. What do these organisms do to the soil? Plants shed leaves which is called litter Litter & dead plants become part of the soil The organisms living there turn the dead organic stuff into humus This process is called decomposition –Decomposers: organisms that break down the remains of dead organisms –Ex: fungi, bacteria, worms

59. Is the soil in Montana the same as in Georgia? NO! Soil is classified into groups according the climate, plants, composition 7 groups: tundra, n. forest, prairie, mountain, s. forest, desert, tropical

60. How do people use soil? Agriculture, development, mining, recreation

61. Is soil important to me & you? YES! Everything needs soil It’s a renewable resource However it can take a long time for new soil to form

62. How is our soil being damaged? Overused Polluted Eroded away Desertification: the advance of desertlike conditions in an area due –Caused by climate change, overgrazing, cutting down trees

63. What was the Dust Bowl? 1930’s Most of the Great Plains had been turned into farm or ranch land This caused the topsoil to dry out and dust to form Lots of people moved away abandoning their farms

64. What does it mean to conserve soil? Soil conservation: the management of soil to prevent its destruction

65. What are some ways to conserve soil? Crop rotation Contour plowing Conservation plowing Windbreaks Terracing

66. Is it possible to restore destroyed land? Yes! Land reclamation: restoring an area of land to a more natural, productive state

67. Where does our trash go? In the soil!

68. Municipal Solid Waste Waste materials produced in homes, businesses, and other places in a community 3 ways of handling solid waste: –Bury it –Burn it –Recycle it

70. Staten Island Landfill New York City

71. Burying Trash PROS –Can be used for parks CONS –Pollute groundwater –Pollute soil –They eventually fill to capacity Landfill: holds solid waste

72. Burning Trash PROS -Doesn’t take up as much space as a landfill -Doesn’t pollute groundwater -Heat produced can be changed into electricity CONS –Pollute the air –Some waste still remains –More expensive than landfills Incineration: burning of solid waste

73. Recycling Trash Recycling: process of reclaiming of reusing raw materials PROS –Conserves nonrenewable resources –Inexpensive –Saves trees –Can be used to make other products CONS –You can’t recycle everything

74. What can you do to help? Reduce, Reuse, & Recycle –Reduce: create less waste in the 1 st place –Reuse: reuse items in your house –Recycle: take your recycling to a local center where they can break it down & make new things from it

75. The Decomposition Times we used were: Glass Bottles/Jars 1,000,000 years Aluminum Cans 80-100 years Plastic Bags 10-20 years Plastic Coated Paper 5 years Orange and Banana Peels 2-5 weeks Newspaper 2-4 weeks