STUDY GUIDE: Chapter 4 Weathering and Soil
Name ______
Geologists use the principle of 1) ______to infer that the rounded, eroded shapes of the Appalachian Mountains have been eroding for millions of years and that newer mountain ranges will erode in similar ways in the future.
Agents of mechanical weathering include: 2)______, freezing and thawing (frost wedging), plant growth, 3)______and abrasion. 4)______is when rock is worn away by the action of other rock particles that are carried away by wind, water and ice.5)______causes mechanical weathering of rock by means of freezing and thawing.
Agents of chemical weathering include: 6)______, oxygen, carbon dioxide, 7)______and acid rain.
8)______in rain water chemically weathers statues and other objects made of 9)______and limestone when left exposed to the weather.
10)______weathering causes the mineral composition of rocks to change.
11)______rocks weather easily because they contain many small, connected airspaces.
The most important factors in determining the rate of weathering are 12)______and 13)______.
Granite and other rocks will weather14)______when the climate is cool and dry. They will weather 15)______in wet and hot climates.
The 16)______, or particle size of soil, determines how much air and water the soil can hold.
Soil that is rich in humus has high 17)______.
The type of soil called 18)______is made up of nearly equal amounts of silt, sand and clay.
Most garden plants grow best in soil with a pH between 19)______.
Soil formation begins with the weathering of 20)______(in the C horizon).
In a cross section of soil, the 21)______horizon consists of clay, minerals and little humus.
In the layer called 22)_____ horizon is where loam that is rich in humus is found.
Most of the work of mixing humus within the soil is done by 23)______.
When earthworms add their wastes to the soil, then die and decay in the soil, they are contributing to the formation of 24)______.
Living organisms in soil help to mix the soil and make 25)______.
Plowing removed the grass from the Great Plains and exposed soil that contributed to the 26)______in the 1930s.
Soil is in limited supply because it takes a 27)______time to form making it a 28)______resource.
29)______describes the management of soil to prevent its destruction.
30)______is the practice of plowing fields along the curves of a slope.
In 31)______, dead weeds and stalks of the previous year are left in the ground to retain moisture and hold the soil in place, preventing erosion.
32)______weathering can cause the loss of soil that is not protected by plant cover.
The advance of desert-like conditions into areas that were once fertile is called 33)______.
The process in which soil becomes less fertile is called 34)______.
Restoring an area of land to a more productive state is called 35)______.
Sometimes we dig for natural resources. What process associated with this activity exposes soil and causes erosion? 36)______
37)______is the layer of soil where the most water and nutrients are absorbed by plant roots.
38) ___litterA. layer of soil above bedrock
39) ___topsoilB. top layer of soil containing dead leaves and grass
40)___subsoilC. the rock that makes up Earth’s crust
41)___bedrockD. layer of soil in which water and nutrients are absorbed by plant roots
Also, study and know information from your Vocabulary Packet,
Review & Reinforce worksheets and Lesson Quizzes!