1. Weathering, Erosion, and Deposition

2. 1. Weathering
Weathering is the breakdown of rock at the Earth’s surface.
Some of these changes happen quickly and some happen slowly.
There are 2 Types:
Mechanical and Chemical

3. 2. Mechanical Weathering
Mechanical Weathering – the type of weathering where rock is broken down into smaller pieces without changing the chemical properties of the rock.
This can be caused by freezing and thawing, release of pressure, growth of plants, and actions of
animals (including
humans).

4. 3. Freezing and Thawing Example: Water seeps into a crack in a rock
When the water freezes, it expands
The force of the water expanding causes the rock to crack more.
This is called ice wedging

5. 4. Plant Growth
Roots of trees and other plants enter into cracks of rocks.
As the plants get bigger, so do the roots.
The growing roots force the cracks further apart.

6. 5. Abrasion
Abrasion is the grinding away of rock by other rock particles.
These particles scrape away at other rocks like sandpaper on wood as they rub or roll against the surface.

7. 6. Chemical Weathering
Chemical weathering is the processes of breaking down rock through chemical changes.
5 things that cause chemical weathering: water, oxygen, carbon dioxide, living organisms (like lichens) and acid rain.
Chemical weathering occurs more rapidly in warm wet climates.

8. 7. Chemical Change
Chemical Weathering causes the rock to experience a chemical change (changes its makeup)
Water dissolves rocks over time
Oxygen causes oxidation (rusting)
Acid rain reacts with marble and limestone
Living organisms – plant roots produce weak acids to dissolve rock around the roots,

9. ACID RAIN
OXIDATION

10. CHECK- UP What type of weathering do each example cause?
A. Chemical Weathering
B. Mechanical Weathering
C. Both types of weathering
What type of weathering do each example cause?
The roots of a plant
An animal scratching
Oxygen
Water freezing
Acid rain
Wind
Water

11. What type of weathering???

12. What type of weathering???

13. What type of weathering???

14. What type of weathering???

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17. What type of weathering???

18. 8. Erosion
When rock and soil are moved from one place to another by natural forces, this is called Erosion.
The agents of Erosion are
Water (rain water runoff, streams, rivers, groundwater, and waves)
Ice (Glaciers)
Wind
Gravity ( landslides,
mudslides, avalanches etc.)

19. 9. Sediment The material moved by erosion is sediment.
Sediment is small, solid particles of rocks or organisms.

20. 10. Deposition
When the sediment being carried is dropped (or deposited) in a new area, it is called deposition.
Depositions can create new landforms like beaches and sand dunes.

21. CHECK-UP Choose one of the following for each example: A.) Erosion
B.)Deposition
A river carrying sand
Dropping sediment in a new location
A glacier picking up a rock in it’s path.
A beach is formed.
How a sand dune is created
How sediment is moved
Sand being carried by the wind in a sandstorm.