Changes to Earth’s Surface.

1. Changes to Earth’s Surface. What Processes Change Landforms?

2. Changing Landforms • The earth’s surface is always changing around you. • Flowing water, waves, wind, ice, internal movements all change existing landforms. • Def: • Landforms-physical features on the earth’s surface

3. What are some of the forces that change landforms? • Write your answer in your notes.

4. A: What are some of the forces that change landforms? • Flowing water • waves • wind • ice • movements inside the Earth transform the landforms or Earth’s surface

5. Water • Much of the earth’s surface is made of rock. • Shaping occurs when weathering wears away rock • Def: Weathering- the process of breaking rock into silt, sand, clay, and other tiny pieces called sediment.

6. Water • After weathering has broken rock into sediment, erosion and deposition move the sediment to new places. • Def: erosion-the process of moving sediment from one place to another. • Def: deposition- the process of dropping or depositing sediment in a new location.

7. Water • Some rivers deposit sediment in wide areas at their mouths, which are called deltas.

8. Wind • Wind also causes weathering and erosion. • Like a sandblaster, it uses particles to erode surfaces. • Wind also carries sediment from place to place. • Wind erodes dry surfaces easier than wet or damp rock.

9. Wind • Sand can be blown into large mounds called dunes. • Beach dunes are built by the constant blowing sea breezes.

10. Sleeping Bear Dunes in Michigan.

11. Ice • Glaciers can also change landforms. • Def: Glaciers- thick sheets of ice, formed in areas where more snow falls in the winter than melts in the summer. • Glaciers are actually moving. • Because of their size and weight, glaciers erode everything under them.

12. Ice • There are two kinds of glaciers: • 1.valley glaciers-found in high mountains valleys, and flow slowly down mountainsides. Only a few left in North America, and even those are melting rapidly.

13. Ice • 2. Continental glaciers- ice sheets that cover large areas of Earth. These are the glaciers that thousands of years ago covered Europe, Canada, and the Northern United States.

14. Mass Movement • When large amounts of soil and sediment move quickly. • Two examples of mass movement are mudslides and landslides. • Def: mudslides- move wet soil. • Def: landslides- move dry soil and rock. • Both occur when gravity becomes stronger than the friction holding the soil in place on a hill.

15. Mass Movement • Def: creep- occurs when soil moves slowly downhill because of gravity. • Creep can occur so slowly that it is hardly noticeable. • Most of the time, it is noticed when things seem out of place, like fences, utility poles, roads, and railroad tracks. Or then a sinkhole can form.

16. Mass Movement • A sinkhole forms when the rock under the soil dissolves or erodes away. • Def: sinkhole- a large hole in the ground that opens suddenly.

17. New Landforms • Glaciers are a major way new landforms occur. • They push mounds of sediment in front of them, and when they melt, the rock and soil leave ridges of new landforms. • Def: terminal moraines- when glaciers melt and leave ridges of sedimentary rock and soil to mark their leading edge of movement.

18. New Landforms • New islands can be formed by volcanic eruptions, especially underwater volcanoes. • Underwater volcanoes increase their height by depositing melted rock and ash. • The Hawaiian islands formed this way. • A new island called Loihi is forming this way, growing slowly on the ocean floor.

19. Questions to answer • What is erosion? • What is deposition? • What is weathering? • Describe how water, wind, and ice cause erosion, deposition, and weathering. • What are glaciers? • What is mass movement? • How do terminal moraines form? • How did the islands of Hawaii form? • How does an oxbow lake form?

20. Questions to answer • What is erosion? • Answer:The process that picks up sediment and moves it elsewhere.

21. Questions to answer What is deposition? • Answer: The process that leaves sediment in other places.

22. Questions to answer • What is weathering? • Answer: the process of breaking rock into silt, clay,and other tiny pieces, called sediment.

23. Questions to answer • Describe how water, wind, and ice cause erosion, deposition, and weathering. • Answer: Water causes weathering,erosion, and deposition when water runs over land formations for a long period of time. When the water flows slows or stops, it deposits the particles that broke off.

24. Questions to answer • Describe how water, wind, and ice cause erosion, deposition, and weathering. • Answer: Wind causes weathering and erosion when it picks up loose particles of soil and rock and blows it around. When the wind stops blowing, it deposits the particles.

25. Questions to answer • Describe how water, wind, and ice cause erosion, deposition, and weathering. • Answer: Ice causes weathering and erosion when the giant glaciers slide against the ground. Deposition occurs when the ice begins to melt and the soil and rock particles it has moved get left behind.

26. Questions to answer • What are glaciers? • Answer: Glaciers are thick slabs or sheets of ice that form in areas of the Earth where it snows more than is able to melt away in the summer.

27. Questions to answer • What is mass movement? • Answer: Mass movement occurs when the gravitation pull overcomes the friction holding the soil in place.

28. Questions to answer • How do terminal moraines form? • Answer: When glaciers melt away, they leave behind long ridges of soil and rock.

29. Questions to answer • How did the islands of Hawaii form? • Answer: Underwater volcanoes formed these islands by building up melted rock and ash until it appears above sea level.

30. Questions to answer • How does an oxbow lake form? • Answer: An oxbow lake forms when a slow moving river forms a broad loop, which eventually closes off and the river forms a new path through the land. The leftover loop forms a crescent shaped body of water.