Jean Kyle, Blossom Gulch, Coos Bay, OR THE CHANGING EARTH Appropriate for grades 3-4. OVERVIEW: One of the basic concepts of Earth Science is that the earth's crust is continually changing. It can be built up or worn down slowly by natural forces or more quickly by people. In our area (coastal Oregon) this concept is relevant because of Mt. St. Helen's recent violent eruption. PURPOSE: The purpose of this activity package is to provide easy and enjoyable science activities and observations which will give students evidence, illustrations and visualizations for some of the changes in the earth's crust. It will also develop in them an awareness of the importance of man's role in sharing with nature in the changes to be made in the future. OBJECTIVES: The student will be able to: 1. Identify by categorizing materials as either chemically or physically weathered 2. Describe how a glacier can change the earth's crust (erratic rocks, hills, scraping) 3. Identify at least five examples of changes in the earth's crust in the neighborhood within walking distance of the school. Students should be able to find such changes caused by man or by nature (construction sites, pavement, tree roots under sidewalks, weathering of buildings, etc.) ACTIVITIES: The activities listed here are designed for 9-10 year olds. However, they can be used with all ages. 1. To demonstrate physical and chemical weathering, take an S.O.S. soap pad and cut it in two (you have just physically changed the pad). Take one half of the pad and put it into a jar of water. It will rust out in a few days (chemical change). It is also easy to show the difference between chemical and physical change by taking a piece of paper and cutting it up (physical change) or by burning it (chemical change). Take your students on a field trip of the play yard at school, record all the evidence of physical and chemical weathering that can be seen on the play yard. 2. Make chunky ice cubes (ice cubes with rocks and sticks in them). Give each student an ice cube to take outside. Find a level area such as a sidewalk and push down on the cube. Watch for scratching and the debris left after the ice has melted. Explain that glaciers change our earth's crust in much the same way - except on a much larger scale. TYING IT ALL TOGETHER: --- JEOPARDY --- Divide the class into groups of three. Have each group brainstorm the answers to questions under the catagories of volcanoes, earthquakes, weathering, glaciers, and plate tectonics. Use the questions to form a Jeopardy Board (you may need to edit or write some questions, too). Depending on the make up and motivation of the group either draw or ask for volunteers to play the game. If interest is high, give additional students the chance to play by using teams rather than individuals or by playing a tournament.
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