Earth Science Chapter 8 – Weathering and Soil Formation
Weathering – _____
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Includes heat, cold, water, ice, and gasses in the atmosphere (oxygen and carbon dioxide)
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Can be seen anywhere there is rock
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2 types _____ and _____
 weathering is a slow process
Erosion – _____
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Weathering and erosion work together to wear down and carry away the rocks at
Earth’s surface
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Uniformitarianism – _____
The same processes that we see today are the ones at work millions of years ago that formed rocks, mountains, valleys, etc that we see now.
Mechanical Weathering
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Rock _____
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Pieces have the same composition as the rocks they came from
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Freezing and thawing (water gets in cracks, expands as it freezes, and makes the cracks bigger) called _____
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Abrasion – _____ (think of sand at the beach wearing grinding on your feet in the water)
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Release of pressure –_____
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Animal actions – moles, etc that burrow break rocks apart
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Plant growth – _____
Chemical Weathering
 process that _____
 can produce new minerals as it breaks down rock
 creates holes or soft spots so it can break apart more easily
 water – _____
 oxygen – iron combines with oxygen in the presence of water in the process called _____, creating _____
 carbon dioxide – _____
 living organisms – plant roots produce _____
 acid rain – _____
Rate of weathering
 type of rock – rocks made of minerals that dissolve easily in water weather quickly
 permeable – _____
weathers chemically quickly because holes _____
 climate – weathering occurs faster in _____ climates
 human activities are also important (creating acid rain…)

Soil – _____. It is a mixture of _____.
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Bedrock – _____. Once exposed to the elements, it weathers into small particles that are the basic ingredient of soil.
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Humus – _____, helps create spaces in soil for air and water plants need
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Fertility of soil is measure of how well the soil supports plant growth. Lots of humus = high fertility.
Soil Texture
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Depends on _____
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Clay, silt, sand, gravel small to large
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Loam – _____
Soil Formation
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Soil formation is always occurring, takes a long time
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Soil horizon – layer of soil that differs in color and texture from the layers around it
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A horizon – _____
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B horizon – _____
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C horizon – _____
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Bedrock
Soil types
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Based on climate, plants, and soil composition
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Tundra, northern forest, prairie, mountain, southern forest, desert, tropical
Organisms
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Litter – _____
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Decomposers – _____
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Worms and burrowing mammals _____
How do we keep soil in place, preventing erosion from moving it?
Sod – _____
Natural resource – anything in the environment that humans use, including soil
Causes of damage and loss
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Overuse by 1 crop takes out nutrients
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Wind and water take topsoil away if no plant cover
Conservation
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Contour farming/step or terrace farming – _____
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Conservation plowing – _____
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Crop rotation – _____
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Step farming – _____