Snackin Plate Tectonics

Transcription

1 Name of group members: Date: Period: Snackin Plate Tectonics Purpose of Activity: To model the interactions of Earth s lithosphere (tectonic plates) as they slowly move on the Earth s upper mantle (asthenosphere), through the use of snack foods. Background for Activity: The theory of plate tectonics says that the crust of the Earth is composed of separate plates which float on the hot, plastic upper mantle. At the boundaries between the plates, the plates may collide, diverge, subduct, or slip past one another. Review the map of Major Tectonic Plates. Review vocabulary related to plate boundaries. Materials for Activity: per group of 2 Snack food key: One sheet of graham cracker (4 crackers) Graham cracker = continental crust ½ of a Fruit Roll Up (cut in 2) Fruit Roll Up = oceanic crust Spoon Frosting = asthenosphere 1 spoon of frosting Piece of wax paper Glass of water YOU WILL NEED COLORED PENCILS TO COMPLETE YOUR DATA TABLES!!! Bring those to class tomorrow. WASH YOUR HANDS BOTH BEFORE AND AFTER THIS LAB ACTIVITY! Procedures for Activity: Ø Read the directions carefully before performing each step. Ø You are responsible for completing all data tables (colored drawings and descriptions) and all comprehension questions (in complete sentences). Ø You are responsible for all clean up you may eat the materials at the end of class. Ø You will switch roles for each section Discussion Leader: Recorder: Reporter: This individual should take the most active role in what the group will be doing. This individual should take the most active role as the writer/drawer in the group. This individual should take the most active role in reporting to me what is happening at that moment in the activity. 1

2 Data Tables and Comprehension Questions: Data tables are to contain before and after drawings. All drawings should be colored and each component of the drawing should be labeled as to what it represents. It may work better to turn the paper sideways when doing the drawings. Changes that can be done as phrases or bulleted lists. All comprehension questions are to be answered in complete sentences. For the activity we used snack foods to model plate movements. Fill in the key with the colors you will use in your drawings. Asthenosphere = Frosting = Continental Crust = Graham Cracker = Oceanic Crust = Fruit Roll Up = Directions for Activity: Obtain about a square foot of wax paper and a large dollop of frosting. Spread frosting into a layer about 1 / 2 a centimeter ( 1 / 4 inch) thick onto the wax paper. FOR EXTRA CREDIT!!! Enrichment Opportunity: As an enrichment opportunity, can take the opportunity to read the article INEVITABILITY OF PLATE TECTONICS ON SUPER-EARTHS at Will need to click on view Article. Plate tectonics may be a necessary condition for life and so the existence of plate tectonics on other earth like/size planets is important for determining whether life may exist on those planets. After reading the article, answer the following questions in writing on a separate piece of paper. 1) Why might plate tectonics be necessary for life to exist on another planet? 2) How can astronomers tell how likely these larger planets are to have plate tectonics. 3) How can astronomers test whether a large planet is tectonically active? 4) How can astronomers test whether a large planet is home to living things? 2

3 I. Divergent Plate Boundary-Oceanic Crust/Oceanic Crust Spread out the asthenosphere with a spoon. Lay 2 pieces of oceanic crust side by side, with the long sides touching. Do the before diagram! Gently press down on the crust (because they are dense and will sink a bit into the asthenosphere) as you pull them away from each other. Do the after diagram! Notice how the frosting is exposed and pushed up where the plates are separated? This is analogous to how magma comes to the surface where real plates are moving apart at divergent plate boundaries. Most divergent plate boundaries are located within oceanic crust. When plates begin to pull apart at continents, rift valleys are made, like the Great Rift Valley in Africa, which can become the bottom of the sea floor if the plates continue to pull apart. Scrape any asthenosphere off the crust and gently lay the pieces of oceanic crust to the side. 1. What happens to the molten rock as two pieces of crust move away from each other? 2. Where on the earth would you expect to find this type of movement? Describe a specific location from the map hanging up in class or using the diagrams in your text. You can't use the examples from above. 3. If new crust is being created at these divergent boundaries, why isn t the earth expanding? (You might want to answer this after the next step) 3

4 II. Transform Plate Boundary-Continental Crust/Continental Crust Spread out the asthenosphere with a spoon. Lay 2 pieces of continental crust side by side, with the long sides touching. Do the before diagram! Slide one piece of crust towards you and one piece of crust away from you, making sure that the long sides are rubbing as you are sliding. Do the after diagram-overhead view! Scrape any asthenosphere off the crust and gently lay the pieces of continental crust to the side. 1. What happens to edges of the crust as the plates move? 2. What type of geologic even occurs as a result of this type of plate movement? 3. Where on the earth would you expect to find this type of movement? Describe a specific location from the map hanging up in class or using the diagrams in your text. 4

5 III. Convergent Plate Boundary-Oceanic Crust /Oceanic Crust Spread out the asthenosphere with a spoon. Lay 2 pieces of oceanic crust side by side, with the long sides touching. Do the before diagram! Gently press down on one piece of the crust (this piece represents the older, denser slab of oceanic crust that will plunge beneath the younger, less dense one) as you slide one piece under the other. Do the after diagram! Leave one piece of oceanic crust on the asthenosphere. Scraping any extra asthenosphere off the other piece. 1. When one piece oceanic crust dives under the other, what type of zone is created? 2. Did the process happen smoothly? Would this affect humans? 3. Where on the earth would you expect to find this type of movement? Describe a specific location from the map hanging up in class or using the diagrams in your text. 5

6 IV. Convergent Plate Boundary-Oceanic Crust /Continental Crust Spread out the asthenosphere with a spoon. Lightly lay 1 piece of continental crust next to the oceanic crust, with the long sides touching. Do the before diagram! Gently press down on the oceanic crust as you slide it under the continental crust. The graham cracker represents continental crust, which is thicker and less dense than oceanic crust (fruit roll up). It floats high on the asthenosphere so don't push it down. The oceanic plate is subducted below the continental one. Do the after diagram! Pick up the remaining piece of oceanic crust and eat it. Scrape the asthenosphere off of the continental crust and put it to the side. 1. What happened along the margins of the oceanic and continental crust? 2. What results at this type of plate interaction? 3. Where on the earth would you expect to find this type of movement? Describe a specific location from the map hanging up in class or using the diagrams in your text. 6

7 V. Convergent Plate Boundary-Continental Crust /Continental Crust Spread out the asthenosphere with a spoon. Place one edge of both crackers into the glass of water for just a 2 seconds each. Lay the 2 pieces of continental crust side by side, with the wet sides touching. Do the before diagram! Slowly push the graham crackers towards each other. Do the after diagram! Notice how the wet edges crumple? This is how mountains are made at continental-continental convergent plate boundaries! When continents move towards each other there is nowhere for the rock to go but up! 1. What happened along the margins of the continental crust? 2. What is the geologic result of this crustal motion? 3. Where on the earth would you expect to find this type of movement? Describe a specific location from the map hanging up in class or using the diagrams in your text. Final step: eat all remaining materials (except, of course, wax paper and plastic utensils!) 7