Mechanical Weathering - Doral Academy Preparatory
Transcript Mechanical Weathering - Doral Academy Preparatory
What is weathering?
The process that breaks
down rock into smaller
pieces, called sediments.
Not to be
There are two types
Rocks are physically
broken into smaller
Rocks are broken down
The rate of weathering is affected by climate.
Mechanical happens faster in the cold weather.
Chemical is faster in warm weather.
Forms of Mechanical Weathering
Plants and animals
(a.k.a. Frost wedging)
The cycle of water freezing and thawing in the cracks
of rocks, causing the rock to break.
Click the picture for ice wedging animation!
Pressure causes rocks to crack and “peel’ away in slabs.
Sediments carried by wind or water rub against other
rock and wear it down. Like sandpaper!
Plant roots grow large and break apart rock.
Animals burrow into the ground and
loosen sediment and soil.
Surface Area of Rock
As rock is broken
apart by mechanical
amount of rock
exposed to air and
pieces will be
than a larger piece.
1. What is weathering?
2. How do mechanical weathering and chemical weathering
3. What type of weather conditions would increase the rate
of chemical weathering?
4. The diagram shows the process of
ice wedging. Explain how this
process physically weathers rocks.
5. How can plants and animals
contribute to the mechanical weathering process?
Forms of Chemical Weathering
When materials that
contain iron are exposed
to oxygen and water, they
become a reddish color.
Ayer’s Rock, Australia
Carbonic acid in rain dissolves rock. This
can form caves and cause sinkholes.
Water combines with the minerals in rock and
cause a chemical change.
If water combines with the mineral feldspar,
clay is formed.
Plant roots give off acids that dissolve rock.
6. Oxidation occurs when materials that contain iron are
exposed to what two compounds?
7. Dissolution can form sinkholes. Explain the process of
8. How do plants and animals chemically weather rocks?
Can you tell which
mountain is older?
What is soil?
A mixture of weathered rock, decayed organic
matters, mineral fragments, water, and air.
Factors Affecting Soil