CORE DEFINITIONS LOOP (repeat this 3–5x)
Weathering = breakdown of rock at or near Earth’s surface.
Erosion = removal of rock by water, wind, glaciers, gravity.
Mechanical weathering = physical breakdown of rock.
Chemical weathering = decomposition by chemical change.
Frost action = water expands 9 percent when frozen.
Soil = mix of sand, clay, humus from weathered rock.
A horizon = leaching, darkest, most humus.
B horizon = accumulation.
C horizon = broken bedrock.