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Science - 4th Grade
Standard 3 Objective 3
1 class periods of 30 minutes each
Soil ingredients are sorted into organic materials and rock sediments.
For the each group of 3-4 students:
The largest percentage of soil (usually about 45%) consists of very small rock particles formed as a result of weathering and erosion (the processes of wearing down rocks into sediments and moving them). Twenty-five percent of a given soil is air. Another twenty-five percent is water. The remaining five percent is organic material, or the remains of plants and animals, called humus. Topsoil (the top-most layer of soil) usually contains more humus than does subsoil (the soil layers under topsoil). Topsoil is usually darker than subsoil.
Ask the student to list four ingredients of soil. Beside each ingredient, ask them to identify it as living, nonliving, or once living.