Pebbles, Sand, and Silt

Grade 2

The Pebbles, Sand, and Silt Module provides experiences with earth science core ideas dealing with the observable structures and properties of earth materials (rocks, soil, and water), weathering and erosion of Earth’s surface, natural sources of water, and how to represent the shapes and kinds of land and bodies of water on Earth.

Investigation 1: First Rocks

Students are introduced to the mineral portion of the planet on which they live. They investigate several kinds of volcanic rocks and begin to understand the properties of rocks. Students observe rocks (using hand lenses), rub rocks, wash rocks, sort rocks, and describe rocks. They also begin to organize a class rock collection to learn about the properties of rocks and the colorful minerals they contain.

Investigation 2: River Rocks

Students investigate a mixture of different sized river rocks. They separate the rocks using a series of three screens to identify five sizes of rocks: large pebbles, small pebbles, large gravel, small gravel, and sand. They add water to a vial of sand to discover silt and clay. Students learn how sand is formed.

Investigation 3: Using Rocks

Students learn how people use earth materials to construct objects. They make rubbings from sandpaper, sculptures from sand, decorative jewelry from clay, and bricks from clay soil. They look for places where earth materials occur naturally and where people have incorporated earth materials into building materials.

Investigation 4: Soil and Water

Students put together and take apart soils. They are introduced to humus as an ingredient in soil. Homemade and local soils are compared. Students read about sources of natural water, sort images of water sources, both fresh and salt, and discuss where water is found in their community. They compare design solutions engineered to slow the effects of wind and water erosion. They learn about different ways to represent landforms and bodies of water.