1. Paste Notes here when done.79
Weathering and Erosion Notes 80
Weathering and Erosion Notes
10/27/14
10/27/14
Starter: Warm Up:
Application/Connection/: Notes
Paste Notes here when done.
Practice:
Architects change the landscape around us all the time, what are natures 4 architects?
Exit: Explain how the landscape is changed by the 4 architects.

2. October 27, 2014 AGENDA
1 Starter 2. Notes 3. Exit
Objective 7.8B Review and Analyze the effects of weathering, erosion, and deposition on the environment in ecoregions of Texas by analyzing and completing notes.

3. Table of Contents Date Lecture/ Activity/ Lab Page
10/ Disaster Writing
10/20 Disaster Mobile
10/ Texas Ecoregions Poster
10/22 Texas Ecoregions Poster and presentation
10/ Unit 5 vocabulary
10/24 Quiz/Writing
10/27 Weathering and Erosion Notes

4. She can plant trees and other vegetation.
The deposit of sediment where a river flows into an ocean or lake
She can plant trees and other vegetation.
She could reduce the slope of the land;

5. Mechanical and Chemical
Weathering
Mechanical
and
Chemical

6. What Caused This?

7. What is Weathering? First step to forming soil and sedimentary rock
Breakdown of rock into smaller pieces
The smaller pieces do not move to a new location until erosion carries them away
Many types of weathering

8. What is Mechanical Weathering?
Breakdown of rock into smaller pieces without any change in the chemical composition of its minerals
Sometimes called “physical” weathering
Rock is torn apart by physical force, rather than by chemical breakdown
Smaller pieces do not move to a new location until erosion carries them away

9. Mechanical - Ice Wedging
Water fills joints of rocks and freezes
Water expands 10% when it freezes, pushes rock apart
Repeated freeze and thaw cycles over the years causes rock to break along joint

10. Mechanical - Exfoliation
Exfoliation or unloading
Rock breaks off into sheets along joints which are parallel to the surface
Caused by expansion of rock due to uplift and removal of surface material that originally buried the rock

11. Mechanical - Thermal Thermal expansion
Repeated daily heating and cooling of rock which causes rock to expand and contract then break
Different minerals expand and contract at different rates causing the rock to split

12. Mechanical - Biotic Biotic – means life
Weathering caused by living organisms
Plant roots act as a wedge and widen cracks
Other causes of biotic weathering are digging animals, microscopic plants and animals, algae and fungi.

13. What is Chemical Weathering?
Breakdown of rock into smaller pieces because of change in the chemical composition of its minerals
Chemical reactions break down the bonds holding the rocks together, causing them to fall apart
Chemical weathering occurs in all types of rock
Rock reacts with water, gases and solutions

14. Chemical - Oxidation
Oxidation - oxygen combines with other elements in rocks to form new types of rock
New substances are usually much softer than original, easier for other forces to break rock apart
Causes a “rusting” of the rock, often causes a color change in the rock

15. Chemical - Carbonation
Carbonation – Carbon dioxide (CO2) is dissolved in water making carbonic acid
Weak acid is formed when CO2 in the air mixes with rain. This is the same acid found in soft drinks. 
Acid is too weak to harm plants and animals but slowly causes feldspars and limestone to decompose

16. Erosion and Deposition
Agents, Forces, and Results

17. What Caused This?

18. What is Erosion?
Erosion - moving of rock material from one place to a new location
For erosion to occur three processes must take place: detachment of particles, lifting them, and transporting them
Many agents of erosion - flowing water, moving ice, waves, gravity, or wind
Sand consists of small pieces of rock that have been weathered from a parent rock, eroded, and deposited somewhere else

19. What Is Wind Erosion?
Wind - responsible for wearing away rocks and creating great deserts like the Sahara Desert and Gobi
Most effective in moving loose material
Two main effects: (1) Wind causes small particles to be lifted and moved away. (2) Suspended particles may impact on solid objects causing erosion by abrasion (rubbing).
Occurs in areas where there is not enough rainfall to support vegetation

20. What Is Water Erosion? Water - most influential force in erosion
Ability to move materials from one location to another over long distances
The faster water moves in streams the larger objects it can pick up and transport
Responsible for wearing away of rocks in rivers, lakes, and the oceans

21. What Is Wave Erosion? Waves - relentless pounding
Erodes the softer, weaker parts of the rock first, leaving harder, more resistant rock behind
Can take over 100 years to erode a rock to sand
Energy of waves along with the chemical content of the water erodes the rock off the coastline

22. What Is Gravitational Erosion?
Mass movement - downward movement of rock and sediments, mainly due to the force of gravity.
Moves material from higher elevations to lower elevations where streams and glaciers can pick up the material and move it to lower elevations
Process is occurring continuously on all slopes, some act very slowly while others occur very suddenly until equilibrium is reached

23. What Is Glacial Erosion?
Ice - moves and carries rocks, grinding the rocks beneath the glacier
Glaciers pluck and abrade to cause erosion
Plucking occurs when water enters cracks under the glacier, freezing, and breaking off pieces of rock that are then carried by the glacier.
Abrasion cuts into the rock under the glacier, smoothing and polishing the rock surface

24. What is Deposition?
Deposition - laying down of sediment that has been transported by a medium such as wind, water, or ice
Process of erosion stops when the moving particles fall out of the transporting medium and settle on a surface. This settling is deposition.
If the speed of the medium slows or the resistance of the particles increases, the balance changes and causes deposition.
Speed can be reduced by large rocks, hills, vegetation, etc.

25. Deposition - Wind
Wind speed can be related to variations in heating and cooling
Wind can transport fine particles in suspension hundreds of km from its original source in the desert.
Heavier material may be blown along the ground.
Material is eventually deposited when the wind changes direction or loses its strength.
Obstacles, whether natural of man-made, will often decide where the deposition occurs and the nature of the feature formed.

26. Deposition - Water
Running water enters a large, fairly still body of water and its speed decreases.
As speed decreases, water's ability to carry sediments decreases
Sediments carried by running water are deposited where the slowing water can no longer move them. Largest particles are deposited near the shore. Increasingly smaller particles settle out farther from the shore where the water is calmer
Occurs in streams, rivers, oceans, etc.

27. Deposition - Ice
Glacial flows of ice - become slower when the ice begins melting
– Deposits left by glaciers are called moraines and
outwashes
– Moraines are large chunks of broken rock left at the base
and sides of the glacier as it melts and recedes
Finer material is carried in the rivers that form when the glacial ice melts. The deposits of these rivers look similar to normal river deposits and are called outwashes

28. What’s the Difference? WEATHERING - think weather wearing rock down
EROSION - think of a road and traveling
DEPOSITION – think of depositing money in a bank

29. Paste Notes here when done.79
Weathering and Erosion Notes 80
Weathering and Erosion Notes
10/27/14
10/27/14
Starter: Warm Up:
Application/Connection/: Notes
Paste Notes here when done.
Practice:
Architects change the landscape around us all the time, what are natures 4 architects?
Exit: Explain how the landscape is changed by the 4 architects.