Learning Resource Type

Lesson Plan

Plate Tectonics: Convection Model- Plates Go With the Flow

Subject Area

Science

Grade(s)

6

Overview

This lesson is the third of a three-part unit on plate tectonics, which includes hands-on, inquiry-based activities. Students will learn about the relationship between temperature and density using lava lamps. The students will also model a theory for the mechanism that drives tectonic plate movement by using a hot plate and water to produce convection cells or currents, and food coloring gels to make the currents visible.

    Science (2015) Grade(s): 6

    SC15.6.9

    Use models to explain how the flow of Earth’s internal energy drives a cycling of matter between Earth’s surface and deep interior causing plate movements (e.g., mid-ocean ridges, ocean trenches, volcanoes, earthquakes, mountains, rift valleys, volcanic islands).

    Unpacked Content

    UP:SC15.6.9

    Vocabulary

    • Crust
    • Mantle
    • Outer core
    • Inner core
    • Lithosphere
    • Plates
    • Tectonic plates
    • Ocean plate
    • Continental plate
    • Asthenosphere
    • Convection
    • Convection current
    • Magma
    • Divergent plate boundary
    • Theory of Plate Tectonics
    • Convergent plate boundary
    • Transform plate boundary
    • Fault
    • Lava
    • Fissure
    • Geyser
    • Rift
    • Basalt
    • Granite
    • Density
    • Ocean trench
    • Subduction
    • Subduction zone
    • Earthquake
    • Mid-ocean ridge
    • Mountain
    • Rift valley
    • Volcano
    • Volcanic island
    • Undersea canyon

    Knowledge

    Students know:
    • The layers of the Earth include, from outmost to innermost, the crust, mantle, outer core, and inner core.
    • The crust and upper mantle are broken into moving plates called the lithosphere. These plates are known as tectonic plates and fit around the globe like puzzle pieces.
    • The asthenosphere is located below the lithosphere. The asthenosphere is hotter and more fluid than the lithosphere. Convection occurs in the asthenosphere.
    • Convection is the transfer of heat by the actual movement of the heated material.
    • Through convection, movements deep within the Earth, which carry heat from the hot interior to the cooler surface, cause the plates to move very slowly on the surface.
    • The Theory of Plate Tectonics states that the outer rigid layer of the Earth is divided into a couple of dozen "plates" that move around across the Earth's surface relative to each other.
    • The areas where plates interact are called plate boundaries.
    • The three types of plate tectonic boundaries include divergent (dividing), convergent (colliding), and transform (grinding past each other).
    • Because ocean plates are denser than continental plates, when these two types of plates converge, the ocean plates are subducted beneath the continental plates. Subduction zones and trenches are convergent margins.
    • Subduction zones form when plates crash into each other, spreading ridges form when plates pull away from each other, and large faults form when plates slide past each other.
    • A divergent boundary occurs when two tectonic plates move away from each other. Along these boundaries, lava spews from long fissures and geysers spurt superheated water. Frequent earthquakes strike along the rift. Beneath the rift, magma—molten rock—rises from the mantle. It oozes up into the gap and hardens into solid rock, forming new crust on the torn edges of the plates. Magma from the mantle solidifies into basalt, a dark, dense rock that underlies the ocean floor. Thus at divergent boundaries, oceanic crust, made of basalt, is created.
    • When two plates come together, it is known as a convergent boundary. The impact of the two colliding plates buckles the edge of one or both plates up into a rugged mountain range called a mid-ocean ridge, and sometimes bends the other down into an ocean trench. Trenches are long, narrow, steep-sided depressions in the ocean floor. A chain of volcanoes often forms parallel to the boundary, to the mountain range, and to the trench. Powerful earthquakes shake a wide area on both sides of the boundary. If one of the colliding plates is topped with oceanic crust, it is forced down into the mantle where it begins to melt. Magma rises into and through the other plate, solidifying into new crust. Magma formed from melting plates solidifies into granite, a light colored, low-density rock that makes up the continents. Thus at convergent boundaries, continental crust, made of granite, is created, and oceanic crust is destroyed.
    • Two plates sliding past each other forms a transform plate boundary. Rocks that line the boundary are pulverized as the plates grind along, creating a rift valley or undersea canyon. As the plates alternately jam and jump against each other, earthquakes rattle through a wide boundary zone. In contrast to convergent and divergent boundaries, no magma is formed. Thus, crust is cracked and broken at transform margins, but is not created or destroyed.

    Skills

    Students are able to:
    • Use a model of the flow of Earth's internal energy and the resulting plate movements and identify the relevant components.
    • Describe the relationships between components of the model including how the flow of Earth's internal energy drives a cycling of matter between Earth's surface and deep interior causing plate movements.
    • Articulate a statement that relates a given phenomenon to a scientific idea, including how the flow of Earth's internal energy drives a cycling of matter between Earth's surface and deep interior causing plate movements.

    Understanding

    Students understand that:
    • The flow of Earth's internal energy drives a cycling of matter between Earth's surface and deep interior. This cycling of matter causes plate movements.

    Scientific and Engineering Practices

    Developing and Using Models

    Crosscutting Concepts

    Energy and Matter

    Primary Learning Objectives

    • Students will identify temperature as a condition that can change the density of a substance and affect the movement of a substance.
    • Students will illustrate and describe how a change in density can cause movement inside the Earth.
    • Students will model convection currents in the Earth’s mantle and explain how these convection cells move the Earth’s plates.

    Procedures/Activities

    Before Strategy/Engage: 50 minutes (Day 1)

    1. The teacher should give each student a copy of the Pre-/Post-Test: Convection. The teacher should give students approximately twenty minutes to complete the pre-test. The teacher should stress to students that the purpose of the pre-test is to demonstrate the student’s background knowledge about the theory of plate tectonics
    2. After students complete the pretest, the teacher should check students’ answers to determine their current knowledge base of the concepts using the Pre-/Post-Test Answer Key. Alternatively, the teacher could allow students to check their own paper or check a partner’s paper.
    3. The students should draw a T-chart on their notebook paper. The left side of the T-chart should be labeled “Old Information” and the right side should be labeled “New Information”. Next, the teacher should give each student a copy of the Background Information handout (see attached document). As students read the passage, they should add notes to their T-chart by listing the information that they have learned about before (“Old Information”) and information that they have not learned before (“New Information”).
    4. After students have read the passage and added notes to their T-chart, the teacher should create a class T-chart to identify the students’ prior knowledge of the concepts that will be taught during this lesson.
    5. The teacher may post the Questions to Ponder on the board and allow students to discuss their answers to further engage students in the topics that will be taught in the remainder of the lesson (see attached document).

    During Strategy/Explore & Explain: (Days 2 and 3)

    Activity A-Convection Currents, Plate Tectonics, and Lava Lamps

    1. Each student will need a copy of Handout A (see attached document). The students should be divided into groups of approximately four students each for this portion of the lesson. Each group will need a lava lamp.
      Note: The teacher should plug in the lava lamps before beginning the activity in order to allow the substances within the lava lamp to heat.
    2. The students should observe the movement of the substances in the lava lamp and answer questions 1-6 on Handout A.

    Activity B-Powering the Movement of the Plates: A Model of a Convection Cell

    1. Each student will need a copy of Handout B (see attached document). The students should be divided into groups of approximately four students each for this portion of the lesson. Each group will need the following materials: tap water, one 1,000 mL beaker, a hot plate, food coloring gel, wood shavings, a sheet of white paper, a wood block the same height as the hot plate, and a bucket for collecting waste water material. Students should follow the procedures described on Handout B and answer the corresponding questions.

    Student Procedures for Lab Activity

    1. Fill beaker approximately half full with tap water.
    2. Place the hot plate and wood block adjacent to each other so that one-third of the beaker diameter is located on the hot plate and the opposite one-third is on the wood block.
    3. After heating the water for a few minutes, gently drop the food coloring gel in the water on the COOL side of the beaker. Try very hard NOT to disturb the water; DO NOT LET THE GEL TOUCH THE SIDE OF THE BEAKER.
    4. Watch and wait for the food coloring gel to drop to the bottom of the beaker and observe the movements that occur. Draw an arrow on the sketch on Handout B to represent the motion of the food coloring as it moves in the beaker (allow approximately 2 to 3 minutes for the movement to begin). In order to follow the movement of the food coloring gel more easily, place a piece of white paper behind the beaker.
    5. What do you think is causing the food coloring to travel in circular paths?
      Note: You may have to change the water several times in order to clearly observe the path of the food coloring. If the water becomes a uniform color, this indicates the food coloring has completely diffused throughout and the convection cell can no longer be observed. Each time you get fresh tap water, you must wait a few minutes for the water to reheat!
    6. Why do you think the food coloring is rising on one side of the beaker while the food coloring on the other side is sinking? What could be the difference between the two sections of water containing the food coloring?
    7. When a substance rises in the beaker, what has happened to its density? What factors can cause a decrease in density?
    8. What is the main difference between the two sections of the water in the beaker?
      • Where is the food coloring gel rising?
      • Where is the food coloring gel sinking?
      • What are the currents called that are created by the rising and sinking of the water?
    9. Pour the water out of the beaker; refill the beaker half full with water. Place it on the hot plate and wood block as before. All the water to reheat for two to three minutes. Place wood shavings in the beaker and observe their motion. Record your findings on Handout B. Are the convection currents strong enough to move the wood shavings?  Explain your answer.
    10. Based on this model and your knowledge of the earth’s interior, how does this experiment give a possible explanation for the theory of plate movement and the cause of drifting of continents?

    After Strategy/Explain & Elaborate: 50 minutes (Day 4)

    1. The teacher should give each student a copy of Handout C and allow students to complete the diagram and reflection questions with their group members.
    2. After all groups have completed the lab activities and Handout C (see attached document), the teacher should lead a class discussion among all of the groups to compare each group’s data.
      Note: If the teacher identifies that students need additional review before the summative assessment, the teacher may show students the Convection-Go with the Flow presentation to review the concepts demonstrated during the lab activities (see attached PowerPoint presentation).
    3. The teacher should give the students the Pre-/Post-Test, that students completed as a pre-test at the beginning of the lesson. The teacher should explain to students that this post-test will allow students to demonstrate the knowledge they acquired during the lab activities.

    Before Strategy/Engage: 50 minutes (Day 1)

    1. The teacher should give each student a copy of the Pre-/Post-Test: Convection. The teacher should give students approximately twenty minutes to complete the pre-test. The teacher should stress to students that the purpose of the pre-test is to demonstrate the student’s background knowledge about the theory of plate tectonics
    2. After students complete the pretest, the teacher should check students’ answers to determine their current knowledge base of the concepts using the Pre-/Post-Test Answer Key. Alternatively, the teacher could allow students to check their own paper or check a partner’s paper.
    3. The students should draw a T-chart on their notebook paper. The left side of the T-chart should be labeled “Old Information” and the right side should be labeled “New Information”. Next, the teacher should give each student a copy of the Background Information handout (see attached document). As students read the passage, they should add notes to their T-chart by listing the information that they have learned about before (“Old Information”) and information that they have not learned before (“New Information”).
    4. After students have read the passage and added notes to their T-chart, the teacher should create a class T-chart to identify the students’ prior knowledge of the concepts that will be taught during this lesson.
    5. The teacher may post the Questions to Ponder on the board and allow students to discuss their answers to further engage students in the topics that will be taught in the remainder of the lesson (see attached document).

    During Strategy/Explore & Explain: (Days 2 and 3)

    Activity A-Convection Currents, Plate Tectonics, and Lava Lamps

    1. Each student will need a copy of Handout A (see attached document). The students should be divided into groups of approximately four students each for this portion of the lesson. Each group will need a lava lamp.
      Note: The teacher should plug in the lava lamps before beginning the activity in order to allow the substances within the lava lamp to heat.
    2. The students should observe the movement of the substances in the lava lamp and answer questions 1-6 on Handout A.

    Activity B-Powering the Movement of the Plates: A Model of a Convection Cell

    1. Each student will need a copy of Handout B (see attached document). The students should be divided into groups of approximately four students each for this portion of the lesson. Each group will need the following materials: tap water, one 1,000 mL beaker, a hot plate, food coloring gel, wood shavings, a sheet of white paper, a wood block the same height as the hot plate, and a bucket for collecting waste water material. Students should follow the procedures described on Handout B and answer the corresponding questions.

    Student Procedures for Lab Activity

    1. Fill beaker approximately half full with tap water.
    2. Place the hot plate and wood block adjacent to each other so that one-third of the beaker diameter is located on the hot plate and the opposite one-third is on the wood block.
    3. After heating the water for a few minutes, gently drop the food coloring gel in the water on the COOL side of the beaker. Try very hard NOT to disturb the water; DO NOT LET THE GEL TOUCH THE SIDE OF THE BEAKER.
    4. Watch and wait for the food coloring gel to drop to the bottom of the beaker and observe the movements that occur. Draw an arrow on the sketch on Handout B to represent the motion of the food coloring as it moves in the beaker (allow approximately 2 to 3 minutes for the movement to begin). In order to follow the movement of the food coloring gel more easily, place a piece of white paper behind the beaker.
    5. What do you think is causing the food coloring to travel in circular paths?
      Note: You may have to change the water several times in order to clearly observe the path of the food coloring. If the water becomes a uniform color, this indicates the food coloring has completely diffused throughout and the convection cell can no longer be observed. Each time you get fresh tap water, you must wait a few minutes for the water to reheat!
    6. Why do you think the food coloring is rising on one side of the beaker while the food coloring on the other side is sinking? What could be the difference between the two sections of water containing the food coloring?
    7. When a substance rises in the beaker, what has happened to its density? What factors can cause a decrease in density?
    8. What is the main difference between the two sections of the water in the beaker?
      • Where is the food coloring gel rising?
      • Where is the food coloring gel sinking?
      • What are the currents called that are created by the rising and sinking of the water?
    9. Pour the water out of the beaker; refill the beaker half full with water. Place it on the hot plate and wood block as before. All the water to reheat for two to three minutes. Place wood shavings in the beaker and observe their motion. Record your findings on Handout B. Are the convection currents strong enough to move the wood shavings?  Explain your answer.
    10. Based on this model and your knowledge of the earth’s interior, how does this experiment give a possible explanation for the theory of plate movement and the cause of drifting of continents?

    After Strategy/Explain & Elaborate: 50 minutes (Day 4)

    1. The teacher should give each student a copy of Handout C and allow students to complete the diagram and reflection questions with their group members.
    2. After all groups have completed the lab activities and Handout C (see attached document), the teacher should lead a class discussion among all of the groups to compare each group’s data.
      Note: If the teacher identifies that students need additional review before the summative assessment, the teacher may show students the Convection-Go with the Flow presentation to review the concepts demonstrated during the lab activities (see attached PowerPoint presentation).
    3. The teacher should give the students the Pre-/Post-Test, that students completed as a pre-test at the beginning of the lesson. The teacher should explain to students that this post-test will allow students to demonstrate the knowledge they acquired during the lab activities.

    Assessment Strategies

    Formative: The teacher will informally assess student’s background knowledge by administering the Pre-/Post-Test prior to teaching the lesson. The teacher can also determine the students’ level of background knowledge of the material by reviewing each student’s T-chart created in the before strategy. The teacher should carefully monitor students as they complete the lab activities with their groups to certify that students are correctly following the lab procedures. The teacher should review each student’s answers to the reflection questions on Handouts A and B to determine student understanding of the concepts demonstrated in the lab activities.

    Summative: The teacher will formally assess students by reviewing each student’s answers on Handout C. This worksheet will allow the teacher to assess student understanding of density and convection, and how these factors affect Earth’s tectonic plate movement. The teacher will administer the Pre-/Post-Test as a summative assessment at the end of the lesson.

    Acceleration

    Students can further explore the topic of Earth’s mantle by completing the Descending into Earth Interactive from ck12.org.

    Intervention

    Students who require additional preparation prior to the lesson or review after the lesson can view the Convection-Go with the Flow Presentation which succinctly summarizes the concepts demonstrated during this lesson’s lab activities.

    Approximate Duration

    Total Duration

    Greater than 120 Minutes

    Background and Preparation

    Background/Preparation

    Student Background Information: As this lesson will serve as an introduction to density and convection currents, and how these factors affect Earth’s tectonic plate movement, students do not need to possess background knowledge about these concepts prior to participating in the lesson’s activities. This lesson will require students to participate in hands-on, inquiry-based lab activities. The students will need to be able to follow multi-step procedural instructions in order to complete the experiments. Students will be participating in lab activities in which a lava lamp and a hot plate will be used. Students should follow all appropriate safety precautions including wearing gloves and goggles.

    Teacher Background Information: This lesson is the third in the Plate Tectonics module. The teacher may wish to incorporate part one (Plate Tectonics: Pangaea-The Supercontinent) and two (Plate Tectonics: Slip, Slidin’ Away) of this module prior to teaching this lesson plan. The teacher should preview the lab procedures and materials prior to teaching the lesson to ensure that the student lab activities are prepared for students before beginning the lesson’s activities. As written, the activities included in this lesson will require at least four class days to complete. The teacher can view the Convection-Go with the Flow Presentation and the Background Information handout for additional background information about the concepts taught in this lesson (see attached files).

    Before beginning the first lab activity, the teacher should plug in the lava lamps to allow them to heat before students begin their observations. As students will be handling lava lamps and hot plates, the teacher should review lab safety precautions with students and ensure students follow these procedures for the duration of the lesson.

    Materials and Resources

    Materials and Resources

    Student Materials

    Pencil or pen

    Pre-/Post-Test: Convection (see attached document)

    Notebook paper

    Background Information (see attached document)

    Handout C-Convection Current Worksheet (see attached document)

    Activity A-Convection Currents, Plate Tectonics, and Lava Lamps

    Handout A (see attached document)

    Materials Needed Per Group:

    Lava Lamp

    Activity B-Powering the Movement of the Plates: A Model of a Convection Cell

    Handout B (see attached document)

    Materials Needed Per Group:

    Tap water

    One 1,000 mL beaker

    Hotplate

    Food coloring gel

    Wood shavings

    Sheet of white paper

    Wood block same height as hot plate

    Bucket for collecting waste water material

    Website for Acceleration Activity: Descending into Earth Interactive from ck12.org

    Teacher Materials

    Pre-/Post-Test Answer Key: Convection (see attached document)

    Questions to Ponder (see attached document)

    Handout A with Answers (see attached document)

    Handout B with Answers (see attached document)

    Handout C-Convection Current Worksheet with Answers (see attached document)

    Convection-Go with the Flow PowerPoint (see attached PowerPoint presentation)

    Technology Resources Needed

    Teacher computer

    Interactive whiteboard or projector

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