Weathering Lesson 4

Graphic organizers—Print off the blank pages for each

student

Mechanical WeatheringForce of Mechanical Weathering

How it Works

Abrasion

Plant Growth

Animal Actions

Freezing and Thawing

Release of Pressure

Chemical WeatheringChemical weathering is___________________________________________________________________________________________________________

Force of Chemical Weathering

How it Works

Water

Oxygen

Carbon Dioxide

Living Organisms

Acid Rain

Mechanical WeatheringForce 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.

Your completed chart

should look like this!

Chemical WeatheringChemical weathering is___________________________________________________________________________________________________________

Force of Chemical Weathering

How it Works

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 reddish-brown 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.

Your completed chart

should look like this!