| A | B |
|---|
| weathering | breaking down of rocks and other materials on the Earth's surface |
| mechanical weathering | weathering that does not make changes in the chemical makeup of rocks |
| exfoliation | breaking off curved sheets or slabs parallel to the rock's surface |
| frost action | when water gets into the rock's cracks and freezes causing rocks to break |
| chemical weathering | weathering that involves changes in the chemical makeup of a rock |
| residual soil | soil that remains on top of the rock from which it was formed |
| transported soil | soil that is moved away from the place it was formed |
| bedrock | layer of rock beneath the soil |
| humus | soil formed by decaying material, making it rich and good for growing (fertile) |
| pore space | space between particles of soil |
| horizon | soil layer |
| soil profile | cross sections of soil horizons |
| topsoil | soil in the "A" horizon |
| subsoil | soil in the "B" horizon, or middle layer of the soil |
