Earth s Plates, Part 1: What Are They, Where Are They and What Do They Do?

Transcription

1 Earth s Plates, Part 1: What Are They, Where Are They and What Do They Do? A scientist named Alfred Wegener believed that, at one time, all of the continents were one landmass. Although he had no real proof, he had a theory that stated that the continents fit together like a puzzle. He called this landmass Pangaea. Wegener thought that these continents eventually drifted apart. After he proposed this, few believed him. It wasn t until scientists found fossils of the same kinds of animals in both South America and West Africa that they started to realize that he might be right. Now, scientists believe that the continents themselves do not move but that very large plates that carry the continents do move. That is what we will be exploring this week. In this inquiry, you will use a model of the earth s plates (made with lasagna noodles) to investigate what could happen where two of the earth s plates meet. Use your activity sheet to record your hypothesis, procedure, data/observations and conclusions. As you work, think about how other landforms that you ve seen or read about might be the result of moving plates on the earth s surface. 1 of 18

2 Earth s Plates, Part 1: What Are They, Where Are They and What Do They Do? Suggested Grade Span 6-8 Task A scientist named Alfred Wegener believed that, at one time, all of the continents were one landmass. Although he had no real proof, he had a theory that stated that the continents fit together like a puzzle. He called this landmass Pangaea. Wegener thought that these continents eventually drifted apart. After he proposed this, few believed him. It wasn t until scientists found fossils of the same kinds of animals in both South America and West Africa that they started to realize that he might be right. Now, scientists believe that the continents themselves do not move but that very large plates that carry the continents do move. That is what we will be exploring this week. In this inquiry, you will use a model of the earth s plates (made with lasagna noodles) to investigate what could happen where two of the earth s plates meet. Use your activity sheet to record your hypothesis, procedure, data/observations and conclusions. As you work, think about how other landforms 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 Measurement 2 of 18

3 Time Required for the Task One to two class sessions for this part of the inquiry activity. Approximately 1 1/2 weeks for the entire unit of study. Context This inquiry is part of a new unit of study in earth science for our classes. (I teach with a partner.) It builds on prior understandings of the earth s history and earth s systems. In the first lesson, students are asked to complete a map activity, The Continents Together (see end-oftask write-up), which introduces and/or reinforces related vocabulary and concepts, including continent, continental drift, fossils, plates, plate tectonics, theory, hypothesis, etc. In class, we discuss the questions on the worksheet. This gives the teacher a chance to preassess prior understandings right from the start. Activity sheets for the investigation with lasagna noodles ( Experiment: Plate Tectonics Theory ) are included with this task to guide the students in using the scientific method. Students are encouraged to formulate a theory about geologic history after a class brainstorm of possible hypotheses. During the lab, students test theories using a model and their observations. I also used an Exemplars activity, "Earth s Plates, Part 2: Movement," as an extension activity after this one. It was a great follow-up to what they had learned. What the Task Accomplishes This activity allows students the opportunity to begin to develop the vocabulary and conceptual understanding of plate tectonics. It is part of our unit, Getting to the Bottom of the Ocean. (Part 2 of this inquiry deals with building submersibles to get to the bottom of the ocean.) Pre-lab discussions and brainstorming about possible hypotheses introduce some of the basic vocabulary related to understanding plate tectonics and using the scientific method. Students apply their observation and analysis skills and work as actual geologists in teams to theorize and identify geological processes through simulation and the use of models. How the Student Will Investigate At the beginning of the unit, students are given booklets with all of the worksheets for the week. I work with a teaching partner, and not all students in both classes are working on the same activities at the same time. Other activities that we include are puzzle activities, which teach students to work cooperatively, and map activities. Students then use the materials provided to build models and investigate plate boundaries. Students manipulate noodles to observe what plates do when they meet. I stress that we are not looking for events like volcanoes or earthquakes in this activity, but rather for some of the more subtle movements of plates. As students work, they notice that plates might slide under each other (subduction) or scrunch up (mountain building). I try to have them discover these 3 of 18

4 actions though experimentation. Students work in teams to investigate what the model does and to begin to describe how this relates to geologic activity. Students compare their findings to the findings of others in the class and to revise theories as appropriate. The ability to articulate basic knowledge and apply it to real world landforms 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. My students moved from this activity to exploring the ocean floor and how scientific research happens at the bottom of the ocean. (See Part 2 of this Exemplars activity.) Social Studies/Geography My students began this unit with a map of the continents and were asked to cut it apart and try to fit the parts together in order to explore continental drift theory. (See worksheet, The Continents Together, included.) Many world geography and map reading skills can be used through encouraging students to find areas around the world where earth s plates can be found. Current events and historical research can track some real-life events (volcanoes and earthquakes) related to moving plates. Geologic timelines are excellent ways to display and connect information as it is learned. Language Arts Students can create class books with factual information about continents and the movement of plates. Students may want to write their own fictional Just So Stories or nonfiction pop up books to explain geologic events and earth s history. Teaching Tips and Guiding Questions I expect students to work in small groups to build and explore models, using the activity sheets as a guide. The lasagna plates can break up while the students work. I explain to students that plates, which are huge, do not actually do this. This is a time to discuss how models can show certain aspects of a concept to help us to understand it but may not be exactly like the real world. Some questions to guide the inquiry might include: Did you observe any plate movements that surprised you? (My students did not expect plates to bunch up or slide under each other.) What does the water in the pan represent? (the upper part of the hot, convecting mantle) Which is larger, a plate or a continent? (plates) If the continent is on top of the plate, what would be happening to it as the plate moves against another plate? What about the ocean above the plate? Have you seen any land formations or pictures of land formations that resemble your 4 of 18

5 model? Can you locate a similar form on a map? Are there any patterns where these landforms are found on the earth? How might a scientist explain the pattern? How does this new information connect with what you ve already studied about the earth's 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 Content) Scientific Method: Students use the terms hypothesis, data, observation, theory and conclusions appropriately; describe cause-effect relationships with some justification, using their data and observations; and observe and explain reactions and trends when variables are controlled (cause and effect). Students build and use models to simulate or explain theories about geologic events that are difficult to observe firsthand. Eath Science Earth Systems and Structures; Earth's History: Students identify the characteristics of geological processes, events (earthquakes, volcanoes, mountain building) and land forms that are the result of plate motions (cause and effect). Mathematics: Students make precise measurements and apply the concepts of compare and contrast. Students collect, organize and analyze data and use diagrams appropriately. 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 global 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 Earth Systems and Structure: Students understand 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 (earthquakes, volcanoes, 5 of 18

6 mountain building) result from plate motions. Students also understand that landforms are the result of constructive (crustal deformation, volcanic eruption, and/or deposition of sediment) and destructive (weathering and erosion) forces. (The lithosphere is made of earth s crust and the upper part of the hot, convecting mantle.) Earth Science Earth s History: Students explain that the earth processes we see today are similar to those that occurred in the past and that fossils provide important evidence of how life and environmental conditions have changed. Suggested Materials The night before this activity, I precook a box of lasagna noodles so that they are flexible but not completely cooked. During the activity, the noodles are placed in plastic bins about 2-3 inches deep with a small amount of water in the bottom. Students work together in teams of three or four to move the plates around and record findings. My teaching partner and I have half the group work on the lab while the rest work on the puzzles. Then we switch activities. For the puzzle activities, any jigsaw puzzles can be used. These can be set up as stations around the room or different groups can do different puzzle activities, or all groups can do all activities. The purpose of these activities is to encourage cooperation and to demonstrate how scientists might have to work together to advance a common theory by putting the pieces together. This is a good class discussion to have at the end of the puzzle activities. Good resources for extending conceptual understanding of this activity include National Geographic ocean floor maps, theory maps that show Pangaea and supercontinents, and other world maps that show continents and/or plate boundaries. My students have to complete several map activities as part of their packets. Refer to worksheets on pages 8, 9 and 10. Possible Solutions Although students worked in groups, each individual was responsible for writing up the lab. All questions should be answered based upon the students' models, hypotheses, data and observations. Students should not include the formation of islands from breaking plates in their conclusions, since this was discussed in reference to using the noodle model. Conclusions should be drawn from data and make a general statement, such as "plates move in different ways." Evidence of applying the scientific method is indicated by stating a hypothesis, collecting data, etc. Task-Specific Assessment Notes Novice The task is not completed. No conclusions are drawn, even though data are collected. Procedures are described - evidence of an attempt to use scientific methodology appropriately. 6 of 18

7 The student states that the noodles broke apart to form islands something that the teachers said would not occur with real plates. Scientific terms, explanations and interpretations are either limited or missing - indicating a lack of understanding of the scientific concepts. Apprentice The task is completed. Conclusions are drawn by restating the data collected. (A more complete conclusion would also summarize patterns or trends.) Procedures are described evidence of an attempt to use scientific methodology appropriately. The student s new hypothesis drops the old conclusions and states that the noodles broke apart to form islands something that the teachers said would not occur with real plates. The student is unsure and simply adds new information without an understanding of the scientific concepts. Practitioner The task is completed. Conclusions are drawn, using the data collected and summarizing that plates move in different ways. There is evidence of appropriate use of scientific methodology. The student s new hypothesis builds on findings. The student s drawing attempts to use scientific terms and shows an understanding of scientific concepts. Expert The task is completed. The original hypothesis is richer and more specific, with ideas based upon prior knowledge. Conclusions are drawn, using the data collected and summarizing that plates move in different ways. There is evidence of appropriate use of scientific methodology. The student s new hypothesis builds on earlier findings and a new investigation indicating an understanding of scientific concepts and reasoning based upon new testing. 7 of 18

8 8 of 18

9 9 of 18

10 10 of 18

11 Novice 11 of 18

12 Novice 12 of 18

13 Apprentice 13 of 18

14 Apprentice 14 of 18

15 Practitioner 15 of 18

16 Practitioner 16 of 18

17 Expert 17 of 18

18 Expert 18 of 18