| A | B |
|---|
| Uniformitarianism | Geological principle that the same geological process that operated in the past to change earth’s surface is the same one working now |
| Erosion | Process by which water ice and wind and gravity move particles of rock and soil |
| Weathering | Chemical and physical process that breaks down rock and other substances |
| Mechanical weathering | Rock is physically broken into smaller pieces |
| Chemical weathering | Process that breaks down rock through chemical changes |
| Abrasion | Grinding away of rock by other rock particles carried in water, ice or wind |
| Frost wedging | Splits rock, water seeps into cracks freezes and expands |
| Oxidation | Substance combines with oxygen, as when iron oxidized, forming rust |
| Permeable | Characteristic of a material that contains connected arir spaces or pores that water can seep through |
| Soil | Loose weathered material on Earth’s surface in which plants grow |
| Bedrock | Rock that makes up Earth’s crust; also the solid rock layer beneath the soil |
| Humus | Dark-colored organic material in soil |
| Loam | Rich, fertile soil made up of about equal parts of clay, sand, and silt |
| Topsoil | Crumbly, topmost layer of solid made of clay and other minerals |
| Subsoil | Layer of soil below topsoil w/ less plant and animal, contains mostly clay and other minerals |
| Decomposer | Organism that gets energy by breaking down biotic wastes and dead organisms and returns raw materials to soil and water |
| Soil conservation | The management of soil to limit its destruction |
| Crop rotation | Planting of different crops in a field of each year to maintain soil’s fertility |
| Contour plowing | Plowing fields along curves of a slope to prevent soil loss |
| Conservation plowing | Soil conservation method in which weeds and dead stalks from the previous year’s crop are plowed into ground |
