| A | B |
|---|
| Weathering | The process that breaks down rock and other substances at Earth’s surface. |
| Erosion | The movement of rock particles by wind, water, ice, or gravity. |
| Mechanical Weathering | The type of weathering in which rock is physically broken into smaller pieces. |
| 5 types of mechanical weathering | Freezing and thawing, release of pressure, growth of plants, actions of animals, and abrasion. |
| Chemical weathering | The process that breaks down rock through chemical changes. |
| 5 agents of chemical weathering | Water, oxygen, carbon dioxide, living organisms, and acid rain. |
| 2 factors that determine rate of weathering | type of rock and climate |
| Soil | The loose, weathered material on Earth’s surface in which plants can grow |
| Bedrock | The soil layer of rock beneath the soil. |
| Of what is soil made? | A mixture of rock particles, minerals, decayed organic material, air, and water. |
| Humus | A dark-colored substance that forms as plants and animals remains decay. |
| Mature soil | Soil that has developed over thousands of years. |
| Soil profile | Cutting a vertical slice of mature soil. |
| Soil horizon | A layer of soil that differs in color and texture from the layers above or below it. |
| A Horizon | the top layer, made of topsoil |
| Topsoil | Dark brown soil that is a mixture of humus, clay, and other minerals. |
| B Horizon | The next layer after the top layer, made of subsoil |
| Subsoil | Composed of clay and minerals washed down by water seeping through the A horizon. |
| C Horizon | the next layer under the B Horizon, mostly weathered rock |
| Parent rock | below the C Horizon, unweathered bedrock |
| Sediment | The material moved by erosion. |
| Deposition | Occurs where the agents of erosion lay down sediment. changes the shape of land. |
| Human activity affecting erosion | logging, mining, farming, construction |
