Changing Earth
How do Soils Form
Layers
Components of Soil
Characteristics of Soil
100
Wind, rain and ice
What are the three factors that cause weathering?
100
Soil Parent Material
What is the first factor that affects soil formation?
100
Bedrock
What is the first layer in a soil profile?
100
Minerals
What is the component in soil that comes from bedrock?
100
Sandy, silty, clay, gravel
What are the different textures you can find in soil? (four)
200
The movement of particles that have been weathered.
What is erosion?
200
Climate: Temperature, rainfall, snow and ice
What influences how parent rocks and sediments are converted into soils?
200
Weathered parent material
What is the second layer that naturally forms in a soil profile?
200
Organic matter
What is the component of soil that comes from biological influences?
200
The chemistry of the soil
What do acids or bases have to do with soil characteristics?
300
Particles which are deposited in one place.
What is depostion?
300
Thin soil on steep slopes, thicker on plains or valley floors.
What is the affect of landscape on soil formation?
300
Sub soil
What is the layer called which has an equal mix of minerals and humus/living organisms?
300
Aerate, move materials, and add to humus when they die and decay or, like earthworms, eat minerals and excrete!
What affect do animals have on soil?
300
The amount of water an object allows to pass, for example a clay like soil repels water, sandy soil absorbs it.
What is permeability?
400
Water or decay cause chemical changes.
What causes chemical weathering in rocks?
400
Organisms, including vegetation and fauna, people and farming
What are all the factors that living things affect in soil formation?
400
Topsoil and ground cover
What are the two layers that we see the most in the soil profile?
400
Air and water
What are two factors that are important for a healthy soil? (hint: deserts have lots of one but not the other)
400
Structure
What characteristic refers to the size of the particles and the amount of nutrients in soil?
500
Mechanical weathering causes physical changes.
What causes physical changes in rocks?
500
Time: 100 years in a warm, wet location, 400 years in a cold, dry location
What affects the length of time soil develops?
500
Residual and transported
What are the two ways soil profiles can be formed?
500
The type of rock formed through plate tectonics will affect how quickly soil forms or what kind of minerals are in the soil.
What is the role of plate tectonics in soil formation?
500
Soil color
What is characteristic that would look different from soil that forms from pumice versus soil that forms from obsidian?
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