In this activity, you will create a model of the earth s surface, using graham crackers and pieces of Styrofoam to represent the earth s plates. Next, you will begin to investigate some of the interactions that take place between plates at their boundaries. You will simulate diverging oceanic plates and converging oceanic and continental plates. Use your activity sheet to record your responses. As you work, think about how other land forms that you've seen or read about might be the result of moving plates on the earth s surface. 1 of 14
Suggested Grade Span 6-8 Task In this activity, you will create a model of the earth s surface, using graham crackers and pieces of Styrofoam to represent the earth s plates. Next, you will begin to investigate some of the interactions that take place between plates at their boundaries. You will simulate diverging oceanic plates and converging oceanic and continental plates. Use your activity sheet to record your responses. As you work, think about how other land forms that you've seen or read about might be the result of moving plates on the earth s surface. Big Ideas and Unifying Concepts Cause and effect Models Systems Earth Science Concepts Earth s history Earth systems and structures Mathematics Concepts Compare and contrast Data collection, organization and analysis Diagrams Graphs, tables and representations Time Required for the Task Approximately 45 minutes. Context Through the use of simple models and simulations, this activity introduces some of the basic vocabulary and earth science concepts related to understanding plate tectonics. The students have already completed an earlier unit of study that included the rock cycle, erosion and weathering, and rock classifications using basic identification strategies. This next unit expands 2 of 14
their understanding of the earth s history and earth s systems by exploring ways the movement of crystal plates create differing land forms. An activity sheet is included with this task and guides the students through the simulations. While this activity is very directive, later lessons should encourage students to raise their own questions to investigate/simulate and to make observations about the geologic history of their immediate environment. What the Task Accomplishes This activity allows students the opportunity to build concrete models of plate tectonic boundaries. It could be incorporated into a unit on oceans, volcanoes, earthquakes or plate tectonics. Prelab vocabulary development allows the teacher flexibility in planning and developing extensions. Defining scientific terms can be used as a pretest of prior knowledge and observation, as vocabulary building, or as an investigation of science content and conceptual understandings. Students apply their observation and analysis skills and work as actual geologists as they study, theorize and identify geological processes through simulations and the use of models. How the Student Will Investigate At the beginning of the lesson, students define the prelab vocabulary. I use this activity to review and build upon vocabulary terms already discussed. Students then use the materials provided to build models of plate boundaries. They will manipulate graham crackers and Styrofoam (crystal plates) on a mound of cake icing (magma). The procedures are divided into two models: divergent plate boundaries (where crystal plates are moving away from each other) and convergent plate boundaries (where crystal plates are moving toward each other). Students will build each model, draw their model and describe what occurs during each geologic activity. Students will compare their drawings with the ocean floor maps in the classroom to find places on the earth that look like their models. The ability to transfer basic, factual knowledge to real-world land forms helps the teacher to identify the conceptual understanding of students from Novices to Experts and to plan for further instruction. Interdisciplinary Links and Extensions Science Many geologic processes can be reviewed or expanded upon using variations of this activity. When plates move together, mountains are created. If the graham cracker breaks, the students have created an earthquake. As magma (cake icing) moves above the graham crackers, students have created a volcano. Another extension could include explaining why earthquakes, volcanoes and sea-floor spreading have a common cause. Breads of different kinds (rye, white, wheat) can be layered to represent different rock layers, with jelly as magma. Simulations of different types of faults can be conducted by cutting the sandwich and shifting halves up and down or side to side. Because the breads are flexible, tilting and folding rock simulations can also be demonstrated (such as the folding in the Alps and Himalayas). Folds can include 3 of 14
monoclines (steep step-like folds), anticlines (which fold up into an arch, e.g., the Jura Mountains) and synclines (downward folds that form a basin, e.g., the London Basin). Social Studies/Geography: World geography and map-reading skills are constantly reviewed by encouraging students to find areas around the world where these processes are occurring. Many social studies and science videos and CD-ROMs are also excellent in providing real-word examples. Language Arts As students become more fluent and confident using scientific vocabulary, they can begin to explore word origins. Words can be broken down into their roots to let students write their own definitions of each word or to encourage students to find other scientific terms that are built on the same roots. Student-created word searches and crossword puzzles are also ways for students to review new terms. Students may want to investigate or write their own myths and legends about geologic events and earth s history. Teaching Tips and Guiding Questions I expect each student to build his/her own model, using the activity sheet as a guide. Place all materials on the piece of wax paper. This will allow the magma (icing) to move more easily. It also keeps everything neat and clean. With every student having his/her own model, you do not need to worry about cleanup. Students can consume each model, wash their Styrofoam square and throw away their wax paper. I have had several students state they will become geologist because their Crystal plates are so good (to eat)! Some questions to guide the inquiry might include: Why is the (thinner, denser) graham cracker a good model for an oceanic plate and (the thicker, less dense) Styrofoam good for representing continental plates? Have you seen any land formations or pictures of land formations that resemble your model? Can you locate a similar form on a map? Are there any patterns with where these land forms (or earthquakes, volcanic action, etc.) are found on the Earth? How does this new information connect with what we ve already studied about the Earth s geologic history? Concepts to be Assessed (Unifying concepts/big ideas and science concepts to be assessed using the Science Exemplars Rubric under the criterion: Science Concepts and Related Concepts) Earth Science Systems; Structures and History: Students identify the characteristics of geological processes. Students explain that major geologic events (earthquakes, volcanoes, mountain building) result from plate motions and that land forms are the result of constructive (crystal deformation, volcanic eruption and deposition of sediment) and destructive (weathering and erosion) forces (cause and effect). 4 of 14
Scientific Method: Students build and use models to simulate or explain theories about geologic events that are difficult to observe firsthand. Mathematics: Students apply the concepts of compare and contrast. Students collect, organize and analyze data and use graphs, tables and representations appropriately. Students understand how to use diagrams. Skills to be Developed (Science process skills to be assessed using the Science Exemplars Rubric under the criteria: Scientific Procedures and Reasoning Strategies, and Scientific Communication Using Data) Scientific Method: Observing, predicting, recording using words and drawings, communicating, using and reading geologic and global relief maps, and interpreting and analyzing application of prior knowledge with new information. Other Science Standards and Concepts Addressed Scientific Method: Students describe, predict, investigate and explain phenomena. Scientific Theory: Students look for evidence that explains why things happen and modify explanations when new observations are made. Scientific Inquiry: Students use systematic observations, precise measurements and prior knowledge to clarify ideas and answer questions. Earth Science Systems; Structures and History: Students explain that lithospheric plates on the scales of continents and oceans constantly move at rates of centimeters per year in response to movements in the mantle and that major geologic events and land forms result from these plate motions. Suggested Materials About a week before this activity, I ask students to bring in materials needed for the lab. I ask for boxes of graham crackers and any flavor of prepared cake icing. You will need at least one box of graham crackers and two tubs of icing for 25 students. I cut Styrofoam picnic plates or recycled meat trays into 3 inch x 3 inch squares. (These can be washed, stored and reused many times.) You will need one square of Styrofoam cut to the size of the cracker per student, one whole graham cracker per student, wax paper, cake frosting, and water and paper towels for clean up. Possible Solutions Prelab vocabulary should be defined using the student's textbook, a dictionary or a science encyclopedia. The teacher may also allow students to develop definitions on their own by 5 of 14
describing the elements of each word. For example, verge (Latin meaning to turn or to incline) means to tend downward, to bend, to slope, to tend, to incline, to approach, to border. Con means with or together. (Definitions obtained from The New Webster Encyclopedic Dictionary of English Language.) A discussion of parts of words will lead to the meaning of convergent i.e., boundaries coming together. All questions will be answered based upon the student-created models. Three types of convergent boundaries are subduction zones, deep sea trenches and mountain ranges. Examples of plate boundaries found on earth are the islands of Japan, the Himalayan Mountains, the Mid-Atlantic Ridge and the Southwest Indian Ocean Ridge. A good resource for this activity is the National Geographic ocean floor maps. Task-Specific Assessment Notes Novice Definitions are complete, and there is an attempt to use scientific vocabulary (e.g., lithosphere, plates) appropriately. This student s drawings do not include directional symbols or scientific terms, and explanations and interpretations are either limited or incomplete indicating a lack of understanding of the scientific terms or their meanings. Map skills are not evident. Apprentice Definitions are complete, and there is an attempt to use scientific vocabulary (e.g., mantle, plates) appropriately. One of the student s drawings includes directional symbols, but neither includes scientific terms. Explanations and interpretations are attempted indicating an understanding of the scientific terms or their meanings. Not all requested geographic regions are identified. Practitioner Definitions are complete, and there is an attempt to use scientific vocabulary (e.g., upper mantle, plate tectonics) appropriately. The student s drawings include directional symbols and scientific terms, yet they are somewhat unclear. (See icing in the second drawing. Also, continental plate should be rising over the ocean plate.) Explanations and interpretations are attempted indicating an understanding of the scientific terms or their meanings. Requested geographic regions are all identified. Expert Definitions are complete, and there is an attempt to use scientific vocabulary (e.g., upper mantle, plate tectonics) appropriately. The student s drawings include directional symbols and scientific terms, and show the differences in thickness of the different plates and the rising action of the continental plate over the oceanic plate. Explanations and interpretations are fuller and more specific indicating an understanding of the scientific terms or their meanings. All requested geographic regions are identified, indicating use of map skills. 6 of 14
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