| A | B |
| acid rain | a weak acid solution formed when rain mixes with pollution |
| chemical weathering | breaking down of earth's surface by changing the chemical composition |
| oxidation | the chemical reaction of rusting |
| physical weathering | mechanical breaking down of rock |
| weathering | slow process of rocks breaking down |
| alluvial fan | like a delta, but it forms upstream where fast-moving water enters a shallow, wide area and slows down, dropping sediment |
| base level | the level at which the stream enters a lake or ocean |
| delta | formed when a stream reaches it base level and deposits its sediment at the mouth of the stream |
| erosion | when weathered materials are carried away |
| floodplain | broad, flat area surrounding a streambed where flooding occurs |
| levee | elevated ridges along rivers built by sediment or man |
| meander | curves in a streambed formed by slow-moving water |
| sediment | soil, sand, rock suspended in water |
| deposition | when material settles to the bottom of a stream |
| particle | small bit of material |
| slope | the angle of incline of a streambed |
| variable | any factor that can change an experiment |