1. Constructive and Destructive Forces
LEQ: How do constructive forces build up the Earth while destructive forces wear down the Earth?(Q)

2. Destructive Forces

3. Sometimes the earth’s surface changes VERY QUICKLY
For Example:
Earthquakes
Landslides Earthquake Landslide
Volcanic eruptions
Tsunamis
Other times, the changes to the earth’s surface occur very SLOWLY
This is known as WEATHERING

4. Weathering Changes the Surface of the Earth
“Weathering” is a general term that describes processes that break down rocks at or near the surface.
Weathering is the process where rock (the earth’s surface) is dissolved, worn away or broken down into smaller and smaller pieces.
weathering exploration
WEATHERING

5. What does “Weathered” mean?
It means the Earth’s solid surface will gradually be broken into smaller and smaller pieces. It happens all the time; it is a natural action.
A LARGE ROCK breaks into pebbles.

6. There are 3 types of Weathering:
Biological
Physical (Mechanical)
Chemical

7. Biological Weathering
Describes the action of living things on the solid surface of the Earth. Roots of plants “digging” into the rock cause it to break apart.
Lichen (fungus) is often found breaking down the surface of the rocks on which it is attached.
Burrowing and digging by animals and insects also contribute to this breaking down process.

8. Tree roots breaking up rock by “digging” into them.

9. AKA mechanical weathering
Physical Weathering
AKA mechanical weathering
Breaks rocks into smaller pieces
When water freezes, it expands. The expansion can break the rock into smaller pieces.
The action of wind blowing small pieces of rock against larger rocks wears rock away.
The movement of running water in streams and rivers cause rocks to weather.

10. Destructive Force Ice © One Stop Teacher Shop
If the pink gorilla eats watermelon every night, how much watermelons does he eat?

11. Physical weathering mechanically breaks up rock.
Frost shattered rock
Frost shattered brick
Physical weathering mechanically breaks up rock.
One example is called frost action or frost shattering. Water gets into cracks and joints in bedrock. When the water freezes it expands and the cracks are opened a little wider
Over time ,pieces of rock can split off a rock and big boulders are broken into smaller rocks and gravel. This process can also break up bricks on buildings.

12. Chemical Weathering Primarily responsible for the formation of soils
It is action that breaks down surfaces chemically.
Carbon dioxide dissolved in rainwater makes a weak acid that dissolves certain rocks such as limestone.
Example: sinkholes

13. Rain water is a very weak acid
Rain water is a very weak acid. It can dissolve limestone and other low carbonate rocks leaving behind pits and holes.

14. Erosion Erosion picks up the pieces and moves them from place to place
Weathering causes the solid surface of the Earth to break down, dissolve and decompose.
Erosion picks up the pieces and moves them from place to place
Therefore, erosion is the process in which surface materials are worn away and transported from one place to another.

15. Once the rock has been weakened and broken up by weathering it is ready for erosion. Erosion happens when rocks and sediments are picked up and moved to another place by ice, water, wind or gravity.

16. Wind erosion weathering Examples of Destructive Force
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Examples of Destructive Force
Wind
erosion
weathering

17. Examples of Destructive Force
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Examples of Destructive Force
Water
Erosion
Weathering

18. Destructive Forces Glaciers Weathering Erosion © One Stop Teacher Shop
If the pink gorilla eats watermelon every night, how much watermelons does he eat?
Erosion

19. Mount St. Helen-Volcano
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Destructive Forces
Mount St. Helen-Volcano

20. If the pink gorilla eats watermelon every night, how much watermelons does he eat?

21. Mount St. Helen’s AFTER the eruption
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Destructive Forces
Mount St. Helen’s AFTER the eruption

22. © One Stop Teacher Shop
Destructive Forces
Earthquakes

23. Earthquakes-Fault Lines
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Earthquakes-Fault Lines

24. © One Stop Teacher Shop
Destructive Forces
Tornadoes

25. Hands-On
Lab on Weathering and Erosion

26. How do we control destructive forces?
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How do we control destructive forces?
If the pink gorilla eats watermelon every night, how much watermelons does he eat?

27. Destructive Forces Dam Large barriers built across rivers and streams
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Destructive Forces
Dam
Large barriers built across rivers and streams
Controls the flow of water
Used for human purposes such as generating electricity

28. A wall created to prevent erosion on the beach
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Destructive Forces
Groin
A wall created to prevent erosion on the beach
If the pink gorilla eats watermelon every night, how much watermelons does he eat?

29. Destructive Forces Beach Nourishment
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Destructive Forces
Beach Nourishment
Sand is pumped from the ocean floor onto the beach
Replaces eroded sand

30. Destructive Forces Contour Plowing Plowing in a zig-zag pattern
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Destructive Forces
Contour Plowing
Plowing in a zig-zag pattern
Prevents water from flowing straight down

31. Storm Drain Management
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Destructive Forces
Storm Drain Management
Drains excess water after storms so less erosion will occur.

32. Destructive Forces Levee Embankment on the edge of a river
Prevents flooding and erosion
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33. © One Stop Teacher Shop
Constructive Forces

34. The process of forming NEW land
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Constructive Forces
The process of forming NEW land
If the pink gorilla eats watermelon every night, how much watermelons does he eat?

35. Constructive Forces Deposition
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Constructive Forces
Deposition
After weathering and erosion occur, the final step is deposition (the sediment is placed somewhere else, forming new land).
Erosion
Weathering
Deposition

36. Deposition Examples of Deposition:
The dropping of sediments that occurs when an agent of erosion, such as gravity, a glacier, wind, or water, loses its energy and can no longer carry its load
Examples of Deposition:
Slump - soils slips down a curved surface
Creep - sediments slowly shift their positions downhill
rock slides- blocks of rock break loose
Mudflows – thick layers of loose sediments activated by water
moraines- ridge build up of till moved by a glacier
sand dunes- sand is deposited by wind
a delta- sediment built up near the mouth of a river

37. Examples of Rocks formed through erosion and deposition

38. DELTA Constructive Forces A triangular area at the mouth of a river
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Constructive Forces
A triangular area at the mouth of a river
Sediment/debris (rocks, sand, dirt) are deposited
Occurs right before the river goes into a larger body of water
WHY? Because the water slows down, so the sediment/debris falls out
DELTA
New land is formed
If the pink gorilla eats watermelon every night, how much watermelons does he eat?

39. Constructive Forces Sand Dunes Sand is carried in the wind
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Constructive Forces
Sand Dunes
Sand is carried in the wind
When the wind stops, the sand drops
New land is formed when the sand drops creating sand dunes (deposition)
New land is formed

40. Constructive Forces FLOODPLAINS New land is formed
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Constructive Forces
A river floods taking sediment/debris (rocks, sand, dirt) with it
The water floods onto the surrounding land transporting nutrients make the land fertile
When the water recedes, the sediment/debris (rocks, sand, dirt) stay forming NEW LAND (deposition)
FLOODPLAINS
New land is formed

41. How Barrier Islands form
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Constructive Forces
How Barrier Islands form
Sand, dirt, and rocks erode of off the main land because of waves
The waves deposit the sand, rocks, and dirt creating an island (deposition)
This creates new land!

42. Constructive Forces Longshore drift
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Constructive Forces
Longshore drift
As a wave hits the beach the longshore current, pushes it sideways
This water then picks up sand/rocks/dirt and carriers it along the
shore
As the wave recedes, it drops the sand/dirt/rocks (deposition) creating new land!!!
New land is formed
If the pink gorilla eats watermelon every night, how much watermelons does he eat?

43. Earthquakes can sometimes be constructive
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Constructive Forces
Earthquakes can sometimes be constructive

44. Fault-block Mountains
Blocks drop down or lift up or tilt
Occur along fault lines
Sierra Nevada range

45. Detour for Earthquake Study
View and complete activities in Earthquake PPT

46. Lab on Locating the Epicenter

47. © One Stop Teacher Shop
Constructive Forces
Volcanoes

48. Volcanoes-RING OF FIRE
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Volcanoes-RING OF FIRE

49. Dome Mountains A form of folded mountain
Just one fold bumps up in the middle
Adirondacks in New York

50. DETOUR for Volcano Study
View and complete activities in Volcanoes PPT

51. Lab on locating earthquakes and volcanoes

52. Your Turn (extend and refine)
Now that you have been introduced the major constructive and destructive forces that change the surface of planet Earth, you have the opportunity to develop your own project or learning adventure related to this topic. You may choose one natural disaster (it must center around a real event) to research and develop a presentation, model, or etc. Examples are a famous hurricane, tornado, earthquake, volcano, tsunami, wild fire, blizzard, drought, flood and many more. You will be responsible for designing your learning and what you present but it must be fact-based and resources included. As a follow- up, you will be required to summarize your learning in at least three paragraphs and have an opportunity to share what you learned with a small group of your peers.

53. More Fun
weathering and erosion joepardy Shape it Up! Erosion Interactive Challenge How do glaciers shape the land? interactive