| A | B |
|---|
| Weathering | Surface processes that break rock into smaller and smaller pieces – can be mechanical (done by growing plant roots, expanding ice or burrowing animals) or chemical (done by reactions with natural acids in the air) |
| Soil | Mixture of weathered rock and mineral fragments, decayed organic matter, water, and air that can take thousands of years to develop |
| Erosion | Process in which surface materials are worn away and transported from one place to another by agents such as gravity, water, wind, and glaciers |
| Deposition | Dropping of sediments that occurs when an agent of erosion, such as gravity, a glacier, wind, or water, loses its energy and can no longer carry its load |
| Runoff | Any rainwater that does not soak into the ground or evaporate but flows over Earth’s surface; generally flows into streams and has the ability to erode and carry sediments |
| Drainage basin | A land area from which a river or stream collects runoff |
| Groundwater | Water that soaks into the ground and collects in pores and empty spaces and is an important source of drinking water |
| Permeable | Describes soil and rock with connecting pores through which water can flow |
| Impermeable | Describes materials that water cannot pass through |
| Aquifer | Layer of permeable rock that allows water to flow through |
| Water table | Upper surface of the zone of saturation; drops during a drought |
| Spring | Forms when the water table meets Earth’s surface; often found on hillsides and used as a freshwater source |
| Geyser | Hot spring that erupts periodically and shoots water and steam into the air – for example, Old Faithful in Yellowstone National Park |
| Cave | Underground opening that can form when acidic groundwater dissolves limestone |
| Beach | Deposit of sediment whose materials vary in size, color, and composition and is most commonly found on a smooth, gently sloped shoreline |
