Heat Up the Floating Plates – Grade Eight
Ohio Standards
Connection:
Earth and Space Sciences
Benchmark E
Describe the processes that
contribute to the
continuous changing of
Earth’s surface (e.g.,
earthquakes, volcanic
eruptions, erosion,
mountain building and
lithospheric plate
movements).
Indicator 12
Explain that some
processes involved in the
rock cycle are directly
related to thermal energy
and forces in the mantle
that drive plate motions.
Lesson Summary:
The purpose of this lesson is to bring students to an
understanding of the connection between the convection
currents within the mantle of the earth and the moving of
Earth’s plates. A connection to lessons at previous grade
levels on the rock cycle and important background
knowledge on rocks is integrated with a pre-assessment and
vocabulary exercise. A teacher demonstration and/or group
activity model the movement of materials through the
mantle of Earth. The post assessment addresses the
concepts and vocabulary used and demonstrated in the
lesson.
Estimated Duration: Two hours
Commentary:
Conceptually, plate tectonics is an abstract topic for young
adolescents. This lesson utilizes a modeling approach to
assist students in comprehending the energy that powers the
process of plate motion.
This lesson was reviewed by teachers across the state of
Ohio. Some of the comments about this lesson were:
“Most eighth graders have difficulty with the concept of
convection because they cannot see it happening. I used
this lesson effectively in conjunction with notes, videos and
other inquiry-based activities.”
Pre-Assessment:
 Have students complete the pre-assessment by responding
to the questions on rocks, the rock cycle and movement of
the Earth’s plates. See Attachment A, Pre-Assessment.
 Read the directions with the students to ensure that they
know they are to circle more than one word for each
answer, if applicable.
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Heat Up the Floating Plates – Grade Eight
Scoring Guideline:
 Evaluate student responses (See Attachment B, Pre-Assessment Answers) to determine if
they are working toward meeting the grade level indicator for this benchmark.
 Provide intervention and/or differentiation for those students working below or beyond
the grade level indicator for this benchmark.
Post-Assessment:
 Have students complete the post-assessment (See Attachment E, Post-Assessment) by
responding to the questions on rocks, the rock cycle and movement of the Earth’s plates.
 Direct students to choose one answer for each question for Part I.
 Inform them that in Part II they are to “Demonstrate” the theory of plate movement and
the connection to thermal energy within the earth by using a diagram.
Scoring Guideline:
 Evaluate student responses (See Attachment F, Post-Assessment Answers) to determine if
they have achieved the grade level indicator for this benchmark. Following the lesson,
students should be able to answer eight of the 11 questions correctly.
 Provide intervention for those students not achieving grade level indicator for this
benchmark.
Instructional Procedures:
1. Administer the pre-assessment.
2. Have students self-correct their own pre-assessment with the class and discuss any
lingering questions about the material.
3. Write the following information on the board:
Thermal Energy in the Earth
The extreme heat in the center of the earth causes convection currents in the
asthenosphere which is made of hot molten material on which the lithospheric plates
move.
N.B. The idea that convection currents move the plates is a scientific theory. The other
information in the above sentence is factual.
4. Discuss this sentence with the class, guiding their understanding of the various terms
associated with the movement of the Earth’s plates.
5. Guide students to select the vocabulary words from the vocabulary list. Have students
develop a personal definition for each word; then use a textbook or reference book check
to make flash cards to include terms and contextual definitions.
6. Explain that students will engage in an activity that models the convection currents
within the Earth’s crust, which provides the energy to produce movement of the Earth’s
plates.
7. Divide the class into small groups of three or four, depending on preferences or the
availability of materials.
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Heat Up the Floating Plates – Grade Eight
8. Have a representative of each group collect the necessary materials and return to the
group. Materials for each group:
 250 ml beaker;
 20 ml molasses;
 40 – 60 ml clear corn syrup;
 three – four pieces of graham cracker;
 600 ml beaker or a small-to medium-sized Pyrex bowl;
 boiled water.
Instructional Tip:
Safety: Use a microwave, electric/gas burner or coffee maker to bring sufficient water to a
boil. Boil enough for each group to have 400 ml of very hot water. Provide students with hot
pads, and instruct them not to touch the container or the water directly.
9. Group members should pour 20 ml of molasses into the 250 ml beaker.
10. Carefully add 40 -60 ml of corn syrup. The corn syrup will sit on top of the molasses if
poured slowly down the edge of the beaker.
11. Place the graham cracker pieces on top of the corn syrup and carefully place the beaker
into the 600 ml beaker (or large Pyrex bowl) of heated water. Do not allow any of the
water to flow into the beaker.
12. Have students record observations of the model for 10 to fifteen minutes.
13. Convection currents are very clear in this demonstration, however, chocolate chunks can
be added in the syrup to model movement of the larger rock material in the molten
matter.
14. Discuss observations and inferences from the modeling.
15. Revisit the terms from the vocabulary activator, or have students list them orally.
16. Have students draw the convection currents and label the core, mantle, asthenosphere and
the lithospheric plates of the earth.
17. It is expected that students label the source of the thermal energy that moves the plates.
18. Discuss real-world evidence and uses of convection currents. Give students a drawing of
a house, and ask them where and how the heated air from the furnace enters rooms. Ask
them to draw the “flow” of air through the room that results from this entrance of
warmth. Other examples are water boiling in a glass pot, a campfire, cold air moving into
a hot shower and a charcoal grill. Have students generate similar ideas they have
experienced.
19. Have students examine samples of the four rocks and read about them in rock guides. If
the samples are not available, a poster of rock types or Internet resources might give the
students some background on the rocks.
20. If samples are available, have students measure the density of each sample. Discuss the
role that the density of these rocks plays in the thermal convection process.
21. If available, turn on a lava lamp so students can see the movement of the material from
bottom to top and back again.
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Heat Up the Floating Plates – Grade Eight
22. Within their groups, have students chart information about the crust, mantle,
asthenosphere, rock cycle, lithospheric plates, thermal energy and convection currents.
These facts should include that the earth’s crust is made up primarily of four rock types:
basalt, gabbro, granite and ryolite.
23. Direct groups to explain their charts to the class. Questions generated from this
discussion should be answered and any misconceptions identified and corrected
immediately. For example students may believe there are hot spots only at plate
boundaries and at the ring of fire. Point out that not all volcanoes are above so-called hot
spots, and not all plate boundaries have hot spots).
24. Administer the post-assessment.
25. Discuss correct responses, and address any additional misconceptions after evaluating
student responses to the post-assessment.
Differentiated Instructional Support:
Instruction is differentiated according to learner needs, to help all learners either meet the
intent of the specified indicator(s) or, if the indicator is already met, to advance beyond the
specified indicator(s)
 Make clay models of the Earth and its interior sections to address learning style
differences.
 Use the skills of choreographers to demonstrate the movement of materials due to
thermal energy in the earth.
 If needed, allow students to use “notes” while taking the Post-Assessment.
 Challenge students to interview an expert on the connection between the convection
currents within the mantle of the earth and the moving of Earth’s plates in the crust and
report back to the class.
Extensions:
 Explore viscosity by adding sugar to the materials in the demonstrations.
 Explore density by adding water to the materials.
 Make a lava lamp using materials that seem appropriate.
Homework Options and Home Connections:
 Visit a natural history museum.
 Ask an expert to give you a hands-on lesson on plate motion that you can share with your
class.
 Make a lava lamp using everyday materials.
Materials and Resources:
The inclusion of a specific resource in any lesson formulated by the Ohio Department of
Education should not be interpreted as an endorsement of that particular resource, or any of
its contents, by the Ohio Department of Education. The Ohio Department of Education does
not endorse any particular resource. The Web addresses listed are for a given site’s main
page, therefore, it may be necessary to search within that site to find the specific information
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Heat Up the Floating Plates – Grade Eight
required for a given lesson. Please note that information published on the Internet changes
over time, therefore the links provided may no longer contain the specific information related
to a given lesson. Teachers are advised to preview all sites before using them with students.
For the teacher:
one bottle of clear corn syrup (0.47L); jar of dark molasses (335 ml [a
ratio of 2 molasses to 3 corn syrup will work]); several graham
crackers; Pyrex bowl or pan with a wide top (9x9); electric burner; hot
pads; goggles; earth science texts, reference books from the library,
such as Earth encyclopedias and the like, black-line master of a house
interior with heat registers near the bottom of the room(s)
For the students:
for each group: 250 ml beaker; molasses, clear corn syrup, pieces of
graham cracker, 600 ml beaker or a small-to-medium sized Pyrex
bowl, boiled water, goggles, earth science texts, chart paper and
markers
Vocabulary:
 rock cycle
 thermal energy
 lithospheric plates
 convection currents
 mantle
 asthenosphere
 lithosphere
 matter
 molten
Technology Connections:
Below are United States Geological Survey Web sites that contain diagrams and explanatory
text for convection currents and platetectonics. These sites have colored diagrams of the
tectonic plates, plate boundaries in action, and plate processes.
http://geology.usgs.gov
http://geology.wr.usgs.gov
Research Connections:
Marzano, Pickering, et.al., Classroom Instruction that Works: Research-Based Strategies for
Increasing Student Achievement. Alexandria, Va. ASCD, 2001.
Cooperative learning grouping has a powerful effect on student learning. This type of
grouping includes the following elements:
 positive interdependence;
 face-to-face interaction;
 individual and group accountability;
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Heat Up the Floating Plates – Grade Eight


interpersonal and small group skills;
group processing.
Using a hands-on activity provides students with a common experience to develop the
concept being taught. From this experience the teacher should facilitate discussion using
carefully designed questions that will draw students to the ideas of the concept to be learned.
The teacher should ask students to constantly refer to data and observations at this time.
Students should practice the new information and have opportunities to transfer the new
knowledge.
General Tips:
 If cost is a factor, warehouse-type stores carry corn syrup in jugs; one or two of these
would last through several classes. Actually, small amounts of molasses and corn syrup
are needed if the beakers used are smaller. Another possibility is to use food coloring and
water (sugar can be added to make the water “thicker” or more viscous); put styrofoam
pieces or blocks of wood on top to demonstrate plate movement. These are reusable.
 Clarify for students that plate boundaries do not necessarily mean there will be volcanic
activity; also, some volcanic activity does not take place at plate boundaries. This will
help students understand better the concept that thermal energy within the earth causes
molten material in earth to become soft like thick tar. When this molten material moves,
the plates move. This movement is very slow.
 You might want to use videos or inquiry-based activities to reinforce the concept of
convection currents.
Attachments:
Attachment A, Pre-Assessment
Attachment B, Pre-Assessment Answers
Attachment C, Post-Assessment
Attachment D, Post-Assessment Answers
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Heat Up the Floating Plates – Grade Eight
Attachment A
Pre-Assessment
Directions: Choose all that apply for each question.
1.
Circle the following words that identify processes in the rock cycle.
Weathering
Cementation
2.
3.
Erosion
Compaction
Melting
Cooling
Circle the terms related to thermal energy.
Conduction
Exothermic Condense
Endothermic
Convection Expansion
Circle the processes in the rock cycle that are directly related to thermal energy.
Weathering
Cementation
Erosion
Compaction
Melting
Cooling
4. Circle the following words that are related to rocks changing inside the Earth.
Great Pressure
High Temperatures
Sedimentation
Magma
Melting
Mantle
5. Circle the types of rocks that can be changed into magma by melting in the Earth.
Sedimentary
Metamorphic
Igneous
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Heat Up the Floating Plates – Grade Eight
Attachment A (continued)
Pre-Assessment
6. Circle the words that are part of the earth’s lithosphere.
Asthenosphere
Crust
Upper mantle
7. Heating rock material in the fluid part of the mantle causes the material to move in a
circular motion. Circle the type of movement.
Radiation
Conduction
Convection
8. Molten rock within the earth rises, cools, falls, melts and rises again. This action moves
Earth’s ___________________.
9. Earth’s lithospheric plates are made up mainly of basalt, gabbro, granite and ryolite,
which are types of ______________.
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Heat Up the Floating Plates – Grade Eight
Attachment B
Pre-Assessment Answers
1.
All six words should be circled.
2.
All six words should be circled.
3.
Melting, cooling
4.
All but sedimentation
5.
All three should be circled.
6.
All three should be circled.
7.
Convection
8.
Plates
9.
Rocks
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Heat Up the Floating Plates – Grade Eight
Attachment C
Post-Assessment
Part I: Choose the correct answer and circle its letter:
1. The lithosphere floats (a) on the asthenosphere because it is completely liquid; (b) on the
asthenosphere because its rocky material is soft and flowing but not completely, liquid;
(c) on the outer core because it is liquid.
2. The lithosphere is (a) cool and rigid and includes the crust and uppermost part of the
mantle; (b) cool and rigid and includes only the crust; (c) cool, but not rigid, and includes
the crust and part of the mantle.
3. The crust of the earth has (a) a thickness of 25 to 50 km; (b) more silicon and oxygen
than the rocks in the mantle; (c) less aluminum than rocks in the mantle.
4. The asthenosphere is made up of material (a) that circulates then cools and sinks; (b) that
is thin and watery because of the heat in the earth; (c) the that has a circular flow due to
conduction.
5. The thermal energy in Earth is related to the rock cycle because (a) the asthenosphere is
partially molten rock; (b) the lithosphere floats on the top of the earth; (c) rocks are made
of minerals.
6. Convection is (a) the circular flow of water within the mantle of the earth; (b) heat energy
spreading outward from a source, from atom to atom; (c) circular flow of matter in
currents in heated material.
7. Convection currents in the mantle of the earth (a) cause plate movements; (b) occur in the
core of earth; (c) make huge rocks move up and down in the mantle.
8. Igneous rocks, such as gabro, granite and basalt, are found in the (a) continental crust; (b)
oceanic crust; (c) both the continental and the oceanic crust.
9. Thermal energy is (a) heat; (b) only found in a thermocline; (c) the opposite of electrical
energy.
10. Forces in the mantle include (a) pressure and heat; (b) pressure and temperature; (c)
convection cells and sinking plates.
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Heat Up the Floating Plates – Grade Eight
Attachment C (continued)
Post-Assessment
Part II
Draw a diagram showing how convection currents are the driving force of plate tectonics.
Include thermal energy, differences in magma moving away from the core of the earth
through the mantle, and movement of convection currents.
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Heat Up the Floating Plates – Grade Eight
Attachment D
Post-Assessment Answers
Post-Assessment Responses
1. b
2. a
3. b
4. a
5. a
6. c
7. a
8. c
9. a
10. a
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