Post on 05-Jan-2016
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RAP 1/22 pg. 41. What is weathering?2. As shown below, an
empty 1,000.-milliliter container has a mass of 250.0 grams. When filled with a liquid, the container and the liquid have a combined mass of 1,300. grams. What is the density?
RAP 1/23 pg 41. The picture below is an example of
what type of weathering?
2. Explain why you think this.
Topic: Weathering, Soil and Erosion
• Chapter 12 in book– Section: 12.1 - Weathering– Section: 12.2 - Soil– Section: 12.3 - Mass Movements & Erosion – Section: 12.4 - Soil as a Resource
Weathering: breakup of rock due to exposure to processes that occur on Earth’s surface
Two types:1. Chemical
-minerals are changed into different substances
2. Mechanical-split or broken into
smaller pieces*no change in composition
1. AbrasionMechanical
Breakdown of rock by grinding action
2. Frost Wedging
MechanicalWater freezes in the cracks of rocks and expands
Root Pry
Lichen - a symbiosis between algae and fungus. Secretes acid. It is the most important producer
of soil from rock.
3. Plant and Animal Activity
Mechanical
Chemical
Roots pry open crackx
Lichen secrete acid
4. Exfoliation
MechanicalPeeling of surface layers
5. Hydrolysis
ChemicalReaction of water with other substances
6. Acids
ChemicalDissolves minerals like calcite and rocks like limestone
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7. Oxidation
ChemicalReaction of oxygen with other substances
Example: rust
Types of Chemical Weathering
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oxidation
acid rain
hydrolysis
RAP 1/29 pg 41. Which rock was most likely found in
the bottom of a riverbed?
2. What type of weathering is responsible for the river rock?
Alka Seltzer Lab
1. Follow along with teacher demonstrations.
2. Answer Alka Seltzer Analysis Questions on pg. 6 (Due 1/30)
RAP 1/30 pg. 8
1.In the alka seltzer lab, what two things changed the weathering rates?
2. Which substance plays the most important role in chemical weathering?
Weathering Quiz (1/30)
Rates of Weathering1. Surface Area
2. Climate
3. Composition
a. More surface exposure = faster
a. Wet = faster; Dryer = slower
a. Faster = shale; Slower = quartz
Where do leaves decay faster?
quartzite
Erosion has stripped away the overlying rock and Seneca Rocks have been uplifted
=differential weathering