||Students learn about Earth materials through their own observations. They learn to distinguish between natural materials and those that have been changed by people. They study natural substances such as rocks and soil, and find that these Earth materials are made up of smaller parts and different components. They learn to use common terms, such as hard, soft, dry, wet, heavy, and light, to describe what they see. These observations help students become familiar with the materials in the world around them in terms of properties and to think about how people use natural materials in various ways.