| A | B |
|---|
| weathering | mechanical or chemical surface processes that break rocks into smaller and smaller pieces |
| mehanical weathering | physical process that breaks rocks apart without changing their chemical makeup; can be cause by ice wedging, animals, and plant roots |
| ice wedging | mechanical weathering process that occurs when water freezes in the cracks of rocks and expands, causing the rock to break apart |
| chemical weathering | occurs when chemical reactions dissolve the minerals in rocks or change them into different minerals |
| oxidation | chemical weathering process that occurs when metallic material is exposed to oxygen and water over time |
| climate | weather pattern that occurs in a particular area over many years |
| soil | mixture of weathered rock, decayed organic matter, mineral fragments, water, and air that can take thousands of years to develop |
| humus | dark-colored, decayed organic matter that supplies nutrients to plants and is found mainly in topsoil |
| horizon | each layer in a soil profile--horizon A (top layer of soil), horizon B (middle layer), and horizon C (bottom layer) |
| soil profile | vertical section of soil layers, each of which is a horizon |
| litter | twigs, leaves, and other organic matter that help prevent erosion and hold water and may eventually be changed into humus by decomposing organisms |
| leaching | removal of minerals that have been dissolved in water |
