1. Weathering Erosion and Deposition
DO NOW:
What is a PHYSICAL change?
What is a CHEMICAL change?

2. 1. Surface area-when more is exposed, more weathering occurs.
Weathering- the process that breaks down rocks into smaller
fragments- resulting in soil.
Rates of weathering are affected by:
1. Surface area-when more is exposed, more weathering occurs.

3. 2. Rock composition- less resistant rocks weather faster.

4. 3.Rocks weather (chemically) faster in hot humid climates
Sinkholes in Guatamala

5. TYPES OF WEATHERING 1.Mechanical Weathering- (disintegration)
breaks rocks without changing the
chemical composition.
a. Abrasion- breaking up of rocks as
they rub against each other

6. b. Biologic activity
Root wedging- roots from plants grow and
break rock
(ex) sidewalk

7. Animals burrow creating more surface area available for weathering to happen on.

8. c. Frost wedging- water seeps into cracks in rock and expands breaking it (ex) pot hole.

9. Exfoliation or upward expansion-
igneous intrusions are exposed and expand from lack of pressure.
<- Agents of Erosion (wind, running water riVers, wave action, glaciers, mass wasting) weather and move layers of sedimentary rock

10. 2. Chemical Weathering (decomposition)- changes molecular structure of rock, making entirely different products.
a. Oxidation- when oxygen unites chemically with minerals in
rock (ex) rust

11. Carbon dioxide + water = carbonic acid
b. Hydration- water unites chemically with minerals in rocks – sometimes makes clay.
c. Carbonation- carbon dioxide unites chemically with minerals in rocks.
Carbon dioxide + water = carbonic acid
which dissolves rocks!
CO2
Oh no!
Slightly
Acidic
Rain!

12. and enzymes on tree roots can decompose rock
d. Biologic Activity:
Hey,
I’m a fun guy!
Lichens, mosses, fungi,
and enzymes on tree roots can decompose rock

13. YOU CAN’T GET SOMETHIN’ FROM NUTTIN’!
CaCO3 + 2 CH3COOH => Ca(CH3COO)2 + CO2 + H2O
Calcium Carbonate
(chalk)
Acetic Acid
(vinegar)
Calcium acetate
(That white stuff on the blue)
Carbon Dioxide
(The bubbles you saw in the beginning of the experiment)
Water
(The reason the chalk looks wet) +
=> + +
The Great Chalk Experiment of 2015!!!
YOU CAN’T GET SOMETHIN’ FROM NUTTIN’!
*N TICE*

15. Remember this?

16. "Cleopatra's Needle”:
                                                                    Obelisk built in 1443 BCE. It was erected first at Heliopolis, Egypt, and moved to Alexandria in 12 BCE by the Romans. Later, presented to the City of New York by the Khedive of Egypt in 1879, and erected in Central Park early in Pink granite; 69 ft. x 8 ft. 21 meters high and weighs about 180 tons.)
Hmmmm….
Why are they different?

17. Chemical weathering of chalk bedrock in England.
Sinkholes:

18. Caves are a result of chemical weathering.

19. How do caves form?
Infiltration happens

20.
What is Erosion?
The MOVEMENT of (weathered) sediment by wind, water, ice or gravity which wears away or lowers Earth’s land surfaces. *Erosion is NOT weathering!

21. What is the result of weathering and erosion?

22. A mature soil profile
Sediment
Transported soil- was brought by an agent of erosion.
Residual soil- weathered native bedrock

24. The End!
How are your notes?