1. Weathering and Erosion

2. Weathering
Alteration of rock materials during exposure to air, moisture, and organic matter.
Responsible for limited changes in the Earth’s surface
Two Types of Weathering
Chemical Weathering
Physical Weathering

3. Rocks
Consists of mixtures of elements and chemical compounds that combine in different proportions to make different kinds of rocks
Rocks include: marble, quartz and feldspar

4. Minerals Elements and compounds found in rocks are called minerals
All minerals are solid and possess a crystal structure
Minerals include diamond (carbon and kaolinite)

5. Physical Weathering
Disintegration or breaking of rock materials into smaller fragments or pieces
Rocks reduced to smaller particles over thousands or millions of years
Chemical components of the rock remain unchanged
6 Important Factors that expose unexposed surfaces to weathering
Freezing and Thawing cycles
Plants and Animals
Temperature
Exfoliation
Gravity

6. EXPOSES NEW SURFACES TO WEATHERING !!
PHYSICAL WEATHERING
EXPOSES NEW SURFACES TO WEATHERING !!

7. Chemical Weathering
Chemicals react with the minerals of the rock to convert them to a new chemical compound
Often these new compounds do not have the same physical properties as the original minerals
Decomposition of rock materials due to chemical reaction of compounds in the rock with the chemicals in the environment

8. Chemical Weathering
Marble consists mostly of calcium carbonate and quartz if exposed to acids it will reach and chemical weathering will occur
Only the calcium carbonate will react not the quartz

9. Chemical Weathering
Naturally occurring chemical that can chemically weather marble is Carbonic Acid Carbonic Acid (H₂CO₃) is formed when Carbon Dioxide (CO₂) mixes with Water (H₂O) in the atmosphere
Occurs very slowly over millions of years
Hydrochloric and sulfuric acids are not found naturally and can create acid rain when factors release chemicals into the air

10. Difference between Physical and Chemical Weathering
Rocks are Physically weathered by breaking them into smaller and smaller pieces.
Rocks are Chemically weathered when compounds in the rock react chemically with another chemical

11. Physical and Chemical Weather Combine to Weather Rocks
By breaking rocks into smaller pieces, physical weathering exposes more of a rocks surface to chemical weathering.
The combination of the two speeds the overall process of weathering

12. Investigation Two

13. Erosion
Erosion occurs when rock and soil is moved from one place to another
Large amounts of rock and soil are transported over large distances
Responsible for the formation of rivers, valleys, canyons, etc.
Disintegrates rock and transport it great distances

14. Erosion
Wind and Water are both capable or moving large amounts of materials over long distances
Wind
Slowly wear down rock until the surfaces of the rock are smooth- windblown sand will help erode rock when particles strike the rock- gradually chipping away
Water
Water flow eventually wear down solid rock if the particles and soil are small enough the water is able to quickly carry them away

16. Rate of Erosion
The amount of erosion that takes places can be decreased so the overall rate of the erosion- how much erodes in a certain period of time- can be slowed
Anything that tends to protect soil and rock from erosion by wind and water will slow the rate of erosion down
Obstacles on a slope will affect the erosion of soil from the slope
Rocks
vegetation: trees, grasses, and other plants

17. What occurs when erosion takes place?
When erosion takes place, soil is moved from one location to another. If erosion occurs on a slope, soil will be washed down the slope

18. Factors Increasing and Decreasing Erosion
Soil from a steep slope will be eroded more than the soil from a less steep slope.
Obstacles such as rocks and vegetation will decrease the erosion of soil from the slope.

19. Investigation Three

20. Soil Mixture of different components
Organic Component
Remains of dead plants animals
Extremely important providing nutrients for other plants to grow
Inorganic Component
Rocks
Result of weathering and erosion
Both weathering and erosion contribute to forming and depositing soil

21. Weathering, Erosion, and Soil
Physical weathering and Erosion tend to help break up rock into smaller particles due to physical grinding and movement of rock.
New rock surface is exposed to chemical weathering each time a small piece breaks off
Erosion helps transport soil materials so that soil may accumulate in certain locations

22. Particles in Soil
Not all rocks are affected the same way by weathering and erosion and result in different sized rock fragments in the soil
Pieces of rocks also provide nutrients from the minerals for plants to grow

23. Soil Components
Some components of soil include, gravel, organic components, and sand

24. Components Different from Each other
Soil components are different chemically and in size.