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Richland Science Lab Grade: 4th Experiment: Graham Cracker Plate Tectonics Question: How are landforms (mountains, volcanos, oceanic trenches) formed? Standards: 4-ESS2-2 Analyze and interpret data from maps to describe patterns of Earth’s features. ESS2.B Plate tectonics and Large-Scale System Interactions: The locations of mountain ranges, deep ocean trenches, ocean floor structures, earthquakes, and volcanos occur in patterns. Most earthquakes and volcanoes occur in bands that are often along the boundaries between continents and oceans. Major mountain chains form inside continents or near their edges. Maps can help locate the different land and water features areas of Earth. Duration: 50 minutes Lesson Components Engage/Explain Explain/Explore Estimated Time 10 minutes 10 minutes Brief Description Discuss plate tectonics and how there are plates in the lithosphere that are constantly moving. Show Pangea, what the Earth looked like 200 million years ago Divergent Plate Boundaries spread apart. Show example in Iceland and recreate with graham crackers and frosting. Explain/Explore 15 minutes Explain/Explore 10 minutes Evaluate 5 minutes Convergent Plate Boundaries collide. Explain there are 3 different types. Review 2 of them and how they formed the Andes and the Himalayas. Recreate with graham crackers, rice cakes, water, and frosting. Transform Plate Boundaries slide against each other causing earthquakes. Model using graham crackers and frosting. Have students test their knowledge by asking questions about the different types of boundaries. If teachers allow, students may eat the graham crackers. Advance Preparation: Check to see if anyone has an allergy to the ingredients in graham crackers, rice cakes and frosting. If a student has allergies, an option for this lab would be to use soft play dough and cardboard cut into rectangles. Buy Graham Crackers, rice cakes, and White frosting. May want to offer gluten free graham crackers for those who have an allergy. Materials Needed: Items may be placed on tray before lesson or may be passed individually for each plate boundary demonstration. Procedure has items passed out individually. Paper plates (1 per child) Graham Crackers (2 per student) White Frosting Rice Cakes (1/2 per student) Markers Knife for spreading frosting Small cup of water for each table For instructor: Power Point Presentation (Plate Tectonics) Computer or tablet Projector Procedure: (Suggested dialog in bold) Engage/Explain (10 minutes) Today we will be learning about plate tectonics. Show PowerPoint slide 1. The Earth’s lithosphere, the rigid outer shell of Earth, consisting of the crust and upper mantle, is made up of a 15 major plates. Show PP Slide 2. These plates are resting atop the hot plastic upper mantle, known as the asthenosphere. These plates may converge or collide, diverge (or separate) or slide past each other. Show PP slide 3. The seven large plates are the African, North American, South American, Eurasian, Australian, Antarctic, and Pacific plates. There are also several minor plates. All of these plates are moving in different directions and at different speeds. Show PP slide 4. Point to the top right picture. This is what Earth looked like 200 Million years ago. Scientists call this version of Earth, Pangea. Let’s look at how Earth has changed in the past 200 Million years. Have students point out what continents have moved in each of the pictures. These plates continue to move today. Some say at a rate of 2-10 centimeters per year, or about how fast your fingernails grow. With the person next to you discuss what you think the Earth will look like in 40 million years and 200 million years from now. Give students a minute to discuss. Show PP Slide 5. There are 3 types of boundaries where the plates touch. They are divergent, convergent, and transform boundaries. Explain/Explore (10 minutes) Show PP Slide 6. Divergent plate boundaries spread apart. Show movement with your hands. Have students copy movement while saying divergent. When the plates move apart it allows magma to come up through the crust. Under the water, the magma cools and creates mountains. Show PP slide 7. The North American plate and the Eurasian plate have divergent boundaries that are spreading. When the plates spread, it allows magma to be released from the Earth. There is a large under water mountain range called the Mid-Atlantic ridge that has formed from magma. This ridge extends from the Arctic Ocean to southern tip of Africa. Iceland is divided along these two plates. On land, the divergent boundaries create volcanos, so when magma is released it flows up through volcanos to become lava. Iceland has 8 active volcanos as seen on the map. In the middle of your table, you will see a plate and a marker for each of you. Using the marker, divide your plate into 4 sections. Using graham crackers and frosting, we are going to show how a divergent plate boundary works. You may not eat our “plates” and “magma”. Once you get your graham cracker square, please break it in two. Someone will also becoming around to place frosting, or magma, in one of your sections. Have one volunteer pass out a graham cracker square out to each student, and one volunteer place a spoonful of frosting in the middle of one section. One of your graham cracker rectangle is representing the North American plate. Please hold that one in the air. Your other one is the Eurasian plate. Now we are going to make the Mid Atlantic Ridge. Lay the two pieces of graham cracker side by side on top of the frosting so they are touching. To imitate the result of diverging oceanic plates, press down on the crackers as you slowly pull apart in opposite directions. Show PP Slide 8.With the person next to you talk about what happened to the frosting between the crackers? What type of feature is produced by this movement? Call on a couple of students to answer these questions after they’ve talked with their partner. Let’s learn about convergent boundaries now. Please push your plate to the center of the table, out of reach, and look back at me. Explain/Explore (15 minutes) Show PP Slide 9. Convergent plate boundaries collide together. Show movement with hands. Have students follow your hand movements while saying convergent. There are three types of convergent plate boundaries. They are oceanic – continental, continental – continental and oceanic-oceanic. Show PP Slide 10. First we are going to concentrate on oceanic continental boundaries. This is where the oceanic crust collides with a continental crust, or land. When these plates collide, the oceanic plate will move under the continental plate, this is called subduction. This forms trenches in the ocean. There are usually steep mountain ranges and large volcanos at the edge of the continent and earthquakes are common. Show PP slide 11. An oceanic-continental convergent plate can be found between Nazca Plate and the South American plate. These colliding plates form the Andes in South America. The Andes are a mountain range that is 4,500 miles long and is in 7 different countries. Notice how many volcanos are present along the mountain range. In another section of your plate, we are going to see what happens when a graham cracker, or the oceanic plate, meets a rice cake, or the continental plate. Have a volunteer pass out ½ rice cake & ½ graham cracker square. Hold up your oceanic plate (a graham cracker). Notice that it a thin but dense plate. Good put that down and hold up your continental plate (a rice cake). It is thicker but less dense. Place the graham cracker and rice cake so they are almost touching, end to end, on top of the frosting. Push the two “plates” slowly toward each other and observe which plate rides up over the other. On the actual surface of the Earth, the oceanic plate is subducted. Does anyone remember what subduction is? Call on one or two students. Subduction is when one plate is forced under another plate. Talk with your partner about the following questions: Show PP slide 12 . Why does the oceanic plate sink beneath the continental plate? . What features are formed on the continent along this boundary? What feature is formed in the ocean along the subduction zone? After students talk with the person next to them, ask these questions to the whole class and call on a few people to answer. We are moving on to Continental-Continental Convergent Plates. Please push your graham cracker plate to the center of the table and look at me. Show PP slide 13 Continent-continent convergence creates some of the world’s largest mountains ranges. Since the continental landmasses have the same rock density, one plate could not be subducted under the other. Magma cannot penetrate this thick crust, so there are no volcanoes, although the magma stays in the crust. With enormous slabs of crust smashing together, continent-continent collisions bring on numerous and large earthquakes. Show PP slide 14. A good example of a large mountain range caused by a two continental plates colliding is the Himalayas. The Himalayas were formed 40-50 Million years ago when the Indian Plate collided with the Eurasian Plate. Does anyone know the name of the Earth’s highest mountain which happens to be in the Himalayas? Mt. Everest. In April 2015, a 7.8 earthquake shook Nepal and triggered an avalanche on Mt. Everest. Let’s show what happens with our graham crackers when two continental plates converge or collide. Have a volunteer pass out one graham cracker square. Have students break in two. Place shallow cup of water on desk. 2-3 students can share a cup. Take two new graham crackers. Each piece of graham cracker represents a continental plate. Dip one end of each of the two graham crackers into a cup of water. Don’t wait too long or they will fall apart. Immediately remove the crackers and lay them end to end on the frosting with the wet edges nearly touching. Slowly push the two crackers together. With a person at your table discuss: show PP slide15 What happens to the wet ends of the graham crackers? What feature do the resulting ends of the wet crackers represent? Name a specific location on the Earth where this type of boundary activity takes place. Call on a few students to answer these questions with the whole class. Explain/Explore (10 minutes) Show PP slide 16. Transform boundaries are the last type of plate boundaries. The plates slide past each other in opposite directions. Show motion with hands. Transform boundaries cause massive earthquakes because they are where large slabs of lithosphere slide past each other. Show PP slide 17. The San Andreas Fault in California is famous for all the earthquakes it’s caused, big and small. Perhaps, you saw the movie San Andreas which was a fictional portrayal of a massive earthquake. Keep in mind that an earthquake could happen along this fault but it would not be as destructive as what’s shown in the movie. Have a volunteer pass out graham cracker squares. Have students break in half. Take two graham cracker pieces and lay the two pieces side by side on top of the frosting so they are touching. Place one hand on each of the graham cracker pieces and push them together by applying steady, moderate pressure. At the same time, also push one of the pieces away from you while pulling the other toward you. * If you do this correctly, the cracker should hold while you increase the push-pull pressure, but will finally break from the opposite forces. We found this one the most difficult to model accurately. With the person next to you discuss: Show PP slide 18 Name a specific location on the Earth where this type of boundary activity takes place. What is the direction of plate motion at a transform plate boundary? Why are transform faults on continents prone to massive earthquakes? Why do you think Earthquakes typically occur in California and not in the midwest? Call on a few students to answer these questions whole group. Evaluate (5 minutes) Which types of boundary plates form volcanos? -divergent, oceanic-continental convergent Which types of boundary plates form mountains? -divergent, convergent Which types of boundary plates cause earthquakes? -divergent, convergent, transform Assuming teacher allows, students may eat their plate boundary types (the graham crackers). Have students throw away plates and uneaten graham crackers. Terminology: Plate Tectonics – a theory that the Earth’s crust (lithosphere) is broken into plates. Divergent Boundaries - where plates spread apart Convergent Boundaries – plates collide Transform Boundaries – plates slide past each other in opposite directions. Lithosphere - the rigid outer shell of Earth, consisting of the crust and upper mantle Asthenosphere - hot plastic upper mantle Lesson Idea from Eva Varga – add website