Weathering Lesson 4
Graphic organizers—
Print off the blank pages for each
student
Mechanical Weathering
Force of Mechanical
Weathering
Abrasion
Plant Growth
Animal Actions
Freezing and Thawing
Release of Pressure
How it Works
Chemical Weathering
Chemical weathering is____________________________________________
_______________________________________________________________
Force of Chemical
How it Works
Weathering
Water
Oxygen
Carbon Dioxide
Living Organisms
Acid Rain
Mechanical Weathering
Force of Mechanical
Weathering
How it Works
Abrasion
Sand and other rock particles carried by wind and
water grind away rock like sandpaper on wood.
Plant Growth
Roots of trees and other plants grow in the cracks of
rocks and pry them apart.
Animal Actions
Animals dig in the soil and loosen and break apart
rocks.
Freezing and Thawing
When water freezes it expands. Ice in the crack of a
rock expands and makes the crack larger.
Release of Pressure
When rocks reach Earth’s surface, reduced pressure
can cause cracks and flakes in the rock.
Chemical Weathering
Chemical weathering is____________________________________________
_______________________________________________________________
Force of Chemical
How it Works
Weathering
Water
Water is the most important cause of chemical weathering. When
a rock dissolves in water, it mixes completely with the water.
Oxygen
A rock containing iron becomes soft and crumbly and reddishbrown in color. It probably has been weathered by
Carbon Dioxide
Carbon dioxide in the air dissolves in rainwater, becoming a weak
acid called carbolic acid. Acids weather rocks such as limestone
and marble.
Living Organisms
Plants, and other living organisms such as lichen, release weak
acids that slowly dissolve rocks.
Acid Rain
Burning coal, oil, and gas for energy produces pollution. This
pollution combines with air and water, to create acid rain, and fast
chemical weathering.