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3rd Gr Rocks & Soil
3rd Grade Rocks and Soil Study Guide
| Term | Definition |
|---|---|
| humus | Material in soil produced by the decomposition of vegetable/animal matter that is needed to fertilize the soil |
| geology | The study of the earth, its history and its rocks |
| minerals | All rocks are made of two or more of these |
| sand | This has large grains with space between grains. It has a rough texture. |
| clay | This has small grains. Water does not move through this easily, and it can be sticky. |
| topsoil | A layer of soil made of decomposed plant and animal material; it is the best soil for growing plants. |
| soil | Loose material that covers much of the earth's surface |
| loam | Soil that contains equal amounts of sand, silt and clay |
| sedimentary | Formed in layers; pressed together over years |
| igneous | Formed when magma cools above or below the ground |
| metamorphic | Formed when rocks are changed by heat or pressure |