 Grade 4 Science
Unit 6: Planet Earth & Its Ever Changing MoonActivity 2: Rocks I (GLE 7, 8, 9, 10, 55)
The teacher will introduce the rock cycle by discussing volcanic processes and the formation of igneous rock. Draw an illustration to represent the information on chart paper. Allow students to observe the samples of igneous rocks that are in the classroom rock collection. Examples are granite, obsidian, basalt, pumice, and scoria (used for landscaping and in gas grills). Then the teacher will prompt students to consider that weathering will begin as soon as igneous material surfaces. The teacher will add weathering to the rock cycle diagram.
Explain that weathered material is deposited into layers by agents of erosion (wind, rivers, and glaciers). The weathered material carried by the agents of erosion is called sediment. As time passes these layers become compressed, or packed, and heat helps them to form the rocks. The rocks that form from sediment are called sedimentary rocks. Ask them if they have ever seen rocks that contained smaller pieces of rocks or fossils. Sedimentary rocks often contain fossils. The teacher will add erosion and deposition to the diagram.
Allow students actually to observe the particle size of sedimentary rock samples using a hand lens. They should also observe the texture of the rocks. The students will define sediment and deposit in their journals and explain how to determine the relative age of one sedimentary layer to another. The teacher will explain that each layer of sediments is covered and buried below other layers before the sediment will become rock. This process will take thousands perhaps millions of years to complete. The teacher will add compaction and compression to the rock cycle diagram. Ask students what happens to the sedimentary rock once it is exposed to the elements. (Weathering) The teacher will add weathering to the cycle. (Note the diagram is not complete at this time and will be added to later.) The students will prepare a roundhouse diagram that illustrates how sedimentary rock is formed.
Suggested websites for diagrams and more information on the rock cycle: WickED Science Stuff: The Rock
Cycle
The Rock Cycle. Find out about the rock cycle and the three kinds of
rocks.
The Rock Cycle. Learn about the rock cycle with the help of a diagram.
How rocks and minerals are
formed. More to explore
Blank Roadhouse Diagram http://www.bioone.org/perlserv/?request=display-figures&name=i0002-7685-64-7-525-f01
United Streaming videos http://www.unitedstreaming.com
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