Weathering and soil review

Mechanical Weathering

Rock is physically broken into smaller pieces.

Chemical Weathering

Rock is broken down through chemical changes.

Weathering

A process that breaks down rocks and other substances at Earth's surface.

Erosion

The movement of rock particles by wind,water,ice or gravity.

Agents of Chemical Weathering

Water,oxygen, carbon dioxide,living organisms, and acid rain.

Agents of Mechanical Weathering

Release of pressure, animal activity, growth of plants, actions of animals and abrasion.

Soil

Loose weathered rock on Earth's surface.

Soil Horizon

A layer of soil that differs in color and tecture from the layer above and below it

Topsoil

A Crumbly dark brown material that is a mixture of humus and other materials. Akso called "A Horizon.

Humus

Dark substance that forms as plants and animals decay.

C Horizon

This layer contains only partly weathered rock.

B Horizon

Also called, "subsoil" and usually consists of clay and other particles washed down from the topsoil layer.

Two Examples of Chemical Weathering

1)Lichen on Stone Mountain produce weak acids that weather Stone Mountain. 2) A rock rusting over time changes to a red or brown color.

Two Examples of Mechanical Weathering

1)A gopher breaks apart rock as he builds his new home. 2) A creepy tree seems to spread its long black roots into rocks breaking them as it grows.

Bedrock

Solid rock

Decomposer

Organisms that break the remains of dead organisms into smaller pieces and digest them with chemicals

Permeable

Means that a material is full of tiny, connected air spaces that allow water to seep through it.