Section 12.1 – Weathering
Weathering can best be described as:
Mechanical
Chemical
What is the connection between the two types:

Types of mechanical weathering
 Frost Wedging
What happens to the volume of water when it
freezes?
Provide a house-hold example of frost wedging:
What type of an environment is frost wedging
common?
How does frost wedging create potholes in the
road?
 Abrasion
Describe the abrasion process:
 Plants and Animals
How do plants help to break rocks into smaller
pieces?
What types of forces are responsible for moving
sand, pebbles, and rocks:
How do animals accelerate the weathering
process?
Important fact to remember: Water is the most efficient and effective type of
mechanical weathering & chemical weathering.

 Carbonic Acid
Carbonic acid forms by:
Types of Chemical Weathering
How does carbonic acid react
with calcite?
 Acid rain
What types of pollutants can help to cause acid
rain?
 Oxidation
Rocks that have been
transformed by oxidation
typically have what color?
What types of structures can be affected and
weathered by acid rain?
Oxidation involves the reaction
of metals with what gas?

What features are formed as
carbonic acid reacts with
calcite?
Which mineral is a red iron
oxide?
Rates of Weathering
 Surface Exposure
Why would a rock broken into several smaller pieces weather faster than a rock of the same size that
is not broken?
Draw and label picture 1
 Composition of Rock
Why is quartz resistant to chemical weathering:
Draw and label picture 2:
Why is quartz resistant to mechanical
weathering:
Why do you think limestone was a good choice for the Egyptians to build the pyramids?
 Climate
Cold and dry climates are conducive to _____ weathering. Hot and wet climates usually have higher
rates of _____ weathering.
Differences in climate can cause rocks to be exposed to different types of weathering. Use the chart
below to answer the questions involving mechanical and chemical weathering.
X-Axis values range from:
Chart Values
5 degrees / 47 cm of rain
Y-Axis values range from:
Type of Weathering
15 degrees / 150 cm of rain
13 degrees / 55 cm of rain
-10 degrees / 80 cm of rain
Colder temperatures and lower levels of precipitation are most
strongly associated with _________ weathering. Whereas
warmer temperatures and higher rates of precipitation are
associated with _______ weathering.
12.2 & 12.4 Soil

Weathering of rocks produces one of Earth’s most valuable resources, soil.
List all the things you can think of that go into the composition of soil:

Mature soils (those that have formed over thousands and thousands of years) often have layers
called horizons. Please complete the table on page 165 regarding soil horizons:
The topsoil in the A-Horizon contains a substance called humus. Humus acts as a natural
fertilizer. What materials go into forming humus?
What is the main type of
erosion for desert soils?
Why do arctic soils have
shallow soil profiles?
What two types of soils have
the deepest soil profiles?
What is “soil depletion”
How have farmers handled soil
depletion
What is the risk of using too
many artificial fertilizers
Windbreaks
Protects against:
Contour farming
Protects against:
Terraces
Protects against:
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