Science Chapter 7

Front 1

weathering

Back 1

mechanical or chemical surface processes that break rocks into smaller and smaller pieces

Front 2

mechanical (or physical) weathering

Back 2

physical process that breaks rocks apart without changing their chemical makeup; can be caused by ice wedging, animals, and plant roots

Front 3

chemical weathering

Back 3

occurs when chemicals reactions dissolve the minerals in rocks or change them into different minerals

Front 4

oxidation

Back 4

chemical weathering process that occurs when metallic material is exposed to oxygen and water over time

Front 5

Effects of climate on soil

Back 5

climate can affect the rate of weathering in different parts of the world. cold climates: rapid mech. warm & wet: rapid chem. dry: slow chem.

Front 6

soil

Back 6

mixture of weathered rock, decayed organic matter, mineral fragments, water, and air that can take thousands of years to develop

Front 7

humus

Back 7

dark-colored, decayed organic matter that supplies nutrients to plants and is found mainly in topsoil

Front 8

horizon

Back 8

each layer in a soil profile

Front 9

3 horizon names

Back 9

horizon A (top layer of soil), horizon B (middle layer), horizon C (bottom layer).

Front 10

soil profile

Back 10

vertical section of soil layers, each of which is a horizon

Front 11

litter

Back 11

twigs, leaves, and other organic matter that help prevent erosion, hold water, and eventually might be changed into humus by decomposing organisms

Front 12

leaching

Back 12

removal of minerals that have been dissolved in water

Front 13

terracing

Back 13

farming method used to reduce erosion on steep slopes

Front 14

human activities that affect soil erosion

Back 14

agricultural cultivation, forest harvesting, overgrazing, and urban construction

Front 15

5 factors that affect soil formation

Back 15

climate, slope of land, types of rock, types of vegetation, and the amount of time rock has been weathering

Front 16

3 ways to prevent soil erosion

Back 16

managing crops, reducing erosion on slopes, and reducing erosion at construction sites

Front 17

erosion

Back 17

process in which surface materials are worn away and transported from one place to another by agents such as gravity, water, wind, and glaciers

Front 18

sediment

Back 18

loose materials, such as rock fragments, mineral grains, and the remains of once-living plants and animals, that have been eroded

Front 19

3 sizes of sediment

Back 19

clay, silt, sand