Earth Science Textbook Chapter 10, “Weathering and Soil formation” Study Guide
Soil is a loose mixture of small mineral fragments, organic material, water, and air that can support the growth of
vegetation.
The source of mineral fragments in the soil is parent rock.
The layer of rock beneath the soil is bedrock.
The organic material formed in soil from the decayed remains of plants and animals called humus.
Soil fertility is the soil’s ability to hold nutrients and to supply nutrients to a plant.
Soil that has a pH of 9 would be considered basic.
Weathering is rock materials broken down by the action of physical or chemical processes.
The breakdown of rock into smaller pieces by physical means is called mechanical weathering.
Small rocks weather more quickly than large rocks because their surface area is larger.
Rocks at higher elevations are exposed to more wind, rain, and ice.
Transported soil is soil that is blown or washed away from its parent rock.
Abrasion is when wind blows sand and silt against exposed rock, eventually wearing away the rock’s surface.
The removal from soil of substances that can be dissolved in water is called leaching
Chemical weathering increases with greater rainfall.
When oxygen in the air reacts with iron, the result is oxidation.
Acid precipitation is rain, sleet, or snow that contains a high concentration of acids.
Explain why a single 500 kg block of granite weathers much more slowly than 100 chunks of granite weighing 5 kg
each.
A rock weathers faster when more of its surface area is exposed. A big block of granite has very little surface area
exposed relative to its large volume. Smaller blocks of granite have the same volume as the larger rock, but they have
a much greater surface area exposed.