WA.4. Earth and Space Science
ES2. Earth Systems, Structures, and Processes
4-5.ES2. Formation of Earth Materials: In prior years, students learned that water plays an essential role in Earth systems, including shaping landforms and weather. In grades 4-5 students learn how Earth materials change and how they can be used for various purposes. They learn that Earth materials include solid rocks and soil, water, and gases of the atmosphere. People use many of these materials as resources to meet their needs. One of the most important Earth resources is soil, since people depend on fertile soil to grow food. The processes that produce soils offer an excellent opportunity for students to understand how Earth materials change gradually over time, and provide a solid grounding for later study of landforms and large-scale changes of Earth's surface that students will learn in middle school.
4-5.ES2B. Students know that weathering is the breaking down of rock into pebbles and sand caused by physical processes such as heating, cooling, and pressure, and chemical processes such as acid rain.
4-5.ES2B.1. Students are expected to describe and give examples of the physical and chemical processes of weathering of rock.
4-5.ES2D. Students know that soils are formed by weathering and erosion, decay of plant matter, transport by rain through streams and rivers, and deposition of sediments in valleys, riverbeds, and lakes.
4-5.ES2D.1. Students are expected to explain how the formation of soils is related to the following processes: weathering of rock; decay of plant matter; transport by rain, streams, and rivers; deposition of sediments in rivers and lakes.