Chapter 5 Flashcards
What is weathering?
The mechanical and chemical processes that change objects on Earth’s surface over time.
What is mechanical weathering? How do mechanical weathering processes break down rocks?
Mechanical weathering is when physical processes naturally break rocks into smaller pieces. Some causes of mechanical weathering are ice wedging, abrasion, plants, and animals.
What is chemical weathering? How do chemical processes change rocks?
Chemical weathering changes the materials that are part of a rock into new materials. Chemical processes that change the rocks include dissolving (by acids and water) and oxidation.
What is soil?
A mixture of weathered rock, rock fragments, decayed, organic matter, water, and air.
How is soil created?
Soil can take thousands of years to form. It is made from the weathering of rocks, which gradually breaks the rocks into smaller fragments. The fragments become good soil when plants and animals live in them, and add organic matter to the fragments of rock.
What are the organic parts of soil?
The organic parts of soil are pieces of leaves, dead insects, waste products of animals, etc. Organic matter like this is formed through decomposition.
What are soil horizons?
Soil horizons are layers of soil formed from the movement of the products of weathering.
Horizon O- top layer, organic layer
Horizon A- Contains much organic matter, likely seen when digging, darker layer, excellent for plant growth
Horizon B- Made up of clay particles, may contain other particles
Horizon C- Made up of weathered parent material (rock or sediments)
Horizon R- Bedrock
Which soil properties can be observed and measured?
Some properties can be observed just by looking at soil, including color. By feeling the soil, you can estimate the amount of sand, silt, and clay. In a laboratory, you can determine exactly what is in each soil. You can determine the suitability for farming by measuring nutrient content and soil pH in a lab.
How are soils and soil conditions related to life?
Soils and soil conditions are related to life because we grow many of our crops with soil, and we need food to eat. Also, some animals live and depend on soil for life.
What is weathering?
the mechanical and chemical processes that change objects on Earth’s surface over time
What is mechanical weathering?
when physical processes naturally break rocks into smaller pieces
What is chemical weathering?
changes the materials that are part of a rock into new materials
