Lesson: The Plates of Earth’s Crust Building a Tectonic Plate Grade level: 5 (3-5) Group size: fewer than 15 Time required: 45 minutes Activity dependency: yes, Layers of the Earth Activity #: 1 of 2 Expendable Cost Per Group: $ 0 Keywords: mantle, crust, continental crust, oceanic crust, tectonic plate. continental drift Summary: In this activity, students model a tectonic plate resting on the mantle using clay and small rocks. While working with the clay, they can begin to visualize how a tectonic plate might move on top of the mantle, the comparative depths of ocean and continental crust, and how plates interact. The activity takes a hands-on, kinesthetic approach to learning about the abstract idea of tectonic plates. Engineering connection: Engineers often must build models to better understand how a system works. Although the Earth’s crust can be observed directly, engineers working with it often need to understand how it works on a larger scale, so building a model is very useful. Related curriculum: subject areas earth science, physical science, geology curricular units landforms activities Plate Puzzle Educational standards: Virginia Science: scientific investigation, reasoning, and logic 5.1e,f Virginia Science: interrelationships in earth/space systems 5.6a Virginia Science: Earth patterns, cycles, and change 5.7c,d Learning Objectives: After this lesson, students should be able to: Understand that the crust is the top layer of the Earth that rests on the mantle and is broken into smaller pieces called plates. Recognize that the plates can move slowly on the mantle and that they can have different thicknesses in different places. Discriminate between oceanic and continental crust based on thickness. Materials List: large chunk of easily moldable clay map of North America shallow bin or basin, preferably circular, large enough to make a 12” diameter plate small rocks or pebbles vegetable oil blue construction paper clear, plastic drinking straws Introduction/Motivation: What is the outermost layer of the Earth called? (crust) How does this layer compare with other layers of the Earth? (made of rock, thinnest layer, people live on it, it moves, etc.) Scientists have evidence that the crust of the Earth is not one large piece, but actually a number of smaller pieces called tectonic plates. What evidence do scientists have? (earthquakes, cracks between plates) Also, there is evidence that the plates of the Earth have been moving slowly over millions of years, a process referred to as continental drift. So, plates can move in two ways – slipping quickly, as in an earthquake, or drifting slowly. The crust of the Earth is what we live on, but there is a thin layer of soil on top of it. However, we can still observe the crust of the Earth directly in some places. How/where? (road cuts through mountains, outcrops of rocks) We cannot see a whole plate at once, though, because the plates are large – many kilometers long and wide. Scientists often make models of things they cannot measure or see directly. How can we make a model of a tectonic plate? (answers vary) Today, we will make a model of the North American plate using clay. We want to make our model as accurate as we can, so we must include features like coastlines, mountain ranges, and lakes, using a map as a reference. Once we have created our plate, we will attempt to recreate its movement slowly on the mantle and measure certain properties of the plate. Procedure: 1. Split students into small groups to take turns working with the clay. Have some students make observations of features that need to be included (peninsulas of Florida and Texas, Rocky Mountain range, for example) and direct other students to mold accordingly. Students should be given 15-20 minutes to create the landmasses and ocean floors of the North American plate to the best of their ability. Groups not working with the clay should be ripping blue construction paper into 1” pieces, or completing step 2. 2. Pour small rocks into the bottom of the basin. We used a circular basin (seen below) and lubricated the rocks using a small amount of vegetable oil. 3. Place the plate on top of the small rocks. Sprinkle the blue construction paper where oceans should be. 4. Slowly move the plate over the rocks. Notice that it ‘floats’ on top of the rocks and the different ways it can move, depending how you move the basin (jerking quickly, moving slowly, etc.). Talk about the properties of the plate, the landmass, and the ocean including mentioning the continental slope, continental rise, and abyssal plain, for an ocean connection. Discuss the difference between continental crust and oceanic crust. 5. While the clay is still malleable, sink several straws into it in different places, but in a horizontal line from the first straw (so the results can be graphed). The clay should fill up the straw to the height of the clay so that when the straws are removed they can be used as a measurement of the depth of the clay. Label the straws continental or oceanic, based on their locations. 6. Graph the height of the clay with distance from the first straw placed. If the first straw was in continental crust, the graph should show a downward trend; if the first straw was in oceanic crust, the graph should show an upward trend. Investigating Questions How is our model of the Earth’s crust the same as the real Earth’s crust? How is our model of the Earth’s crust different than the real crust? What are the differences between oceanic and continental crust? Is our model of the mantle accurate? What do you think happens to the edges of plates when they move into each other? Assessment Pre-Assessment Review the layers of the Earth. Ask simple questions about the crust such as what is the crust made out of? is the crust one large piece or many small pieces are there different kinds of crust? Post-Assessment Ask students to draw a profile of the crust, giving them a starting place (middle of a mountain range, for example), and an ending place (abyssal plain of the ocean). See if they can include a lake, the continental slope, the continental rise, etc. Figure 1: The circular red basin we used to create our tectonic plate. Plate Puzzle Grade level: 5 (3-5) Group size: fewer than 15 Time required: 45 minutes Activity dependency: yes, Layers of the Earth Activity #: 2 of 2 Expendable Cost Per Group: $ 0 Keywords: crust, tectonic plate, convergent plate boundary, transform fault boundary, divergent plate boundary, subduction zone, mountainbuilding, rift Summary: In this activity, students create a map of Earth’s major (and minor, if desired) tectonic plates. They label and classify the plates as mostly oceanic or continental. They also begin to see how the plates may interact when they move together or apart – creating mountains or rifts. They can also begin to see the different boundaries between plates. Engineering connection: Engineers often must build models to better understand how a system works. Although the Earth’s crust can be observed directly, engineers working with it often need to understand how it works on a larger scale, so building a model is very useful. Related curriculum: subject areas earth science, physical science, geology curricular units landforms activities Building a Tectonic Plate Educational standards: Virginia Science: scientific investigation, reasoning, and logic 5.1e,f Virginia Science: interrelationships in earth/space systems 5.6a Virginia Science: Earth patterns, cycles, and change 5.7c,d Learning Objectives: After this lesson, students should be able to: There are eight major and many minor plates of the Earth. They should be able to name most. Notice areas where plates are moving together or apart, and the effects of that movement. Begin to understand the different boundaries between plates including subduction zones, transform faults, convergent and divergent boundaries. Materials List: projector large piece of white paper different colored paints, crayons, colored pencils, or markers black marker Map of the Plates of the Earth (see attached) Velcro 2”x2” pieces of card stock for labels Introduction/Motivation: How many plates are there on the Earth? Are they small or large? What are they called? Earth’s major plates all have both continental and oceanic crust and each continent appears to rest on a different plate. The plates are not stationary – in fact, they are moving constantly, at a rate of 6-15 cm/year, depending on the plate. This movement is called continental drift. The continents have been drifting for millions of years, forming different landmasses each time they come together or separate. What are the consequences of plates banging into each other? Have students model convergent and divergent plate boundaries with their hands by holding their hands parallel to each other and pushing them together or separating them. They should be able to see that at a convergent boundary, land will be pushed up (mountainbuilding) and at a divergent boundary, a great divide, or rift will form. In some areas, one plate will be pushed under another plate, and this is called a subduction zone. Creating a map of the plates will give students an idea of the size and extent of individual plates, and how the movements has effects on Earth. Tie this activity to the Building a Tectonic Plate Activity by reviewing the features of plate that the class built. Procedure: 1. Hang the white paper up on a clear wall, perhaps in the hallway if there is no room in the classroom. 2. Using the projector, project the Map of the Plates onto the wall. Discuss the plates, showing how there are some small plates and some larger plates, and how each continent appears to rest on a separate plate. Point out significant features between plates like the Himalayan and Andes mountain ranges and the Ring of Fire. 3. Have students take turns drawing the outlines of the plates with black markers. 4. The students should begin painting or coloring the plates different colors, taking turns. 5. Once the map is completely painted/colored, draw in the arrows with the black marker showing how the plates are moving. Discuss how some plates are moving away from each other and some are moving into each other, and the effects of that movement. 6. Have students create labels of the plate names out of card stock and Velcro them to the center of the individual plate. Also, create a key with the color of the plate and the plate label. Investigating Questions: How is the Earth’s crust similar to a puzzle? How is it different? What do you think happens when a rift is formed? Does anything fill in the rift? When one plate goes under another plate, it is called a subduction zone. What do you think happens to the plate that goes above? What about the plate that goes below? When plates come together, a mountain is built. How long do you think it takes to create a mountain? Assessment: Pre-assessment Review the facts about continental drift. A short assessment can be given asking questions such as what are the layers of the Earth? is the crust of the Earth one large piece or many small? is the crust moving? Post-assessment One of the advantages of creating a map like this is that it can be constantly referenced and used for games and assessments. You can individually assess each student’s knowledge of the major and minor plate names, plate movements, and the consequences of plate tectonics (mountain ranges, rift valleys, faults).