Mini-Unit:
Plates on the Move

Performance Standard A7, Level 3

Students will use models to explain how large scale movements within the Earth’s interior cause changes on the Earth’s surface.

Key Concepts and Skills

• Solid earth is divided into several layers: a thin crust, the solid lithosphere, the mantle layer, and a dense metal core.
• Heat flow and convection currents within the mantle cause motion of the lithospheric plates; continental plates and the ocean floor move at rates of centimeters per year.
• Major geological events such as earthquakes, volcanic eruptions, and mountain building are the result of motion of the tectonic plates.
• Skills: Observe, develop models and hypotheses, experiment, communicate; transfer concepts, record data, summarize data, interpret data, report orally; use reference materials, deliver a presentation, measure, sketch, write, compare, plan, design.

Timeline

Up to twenty days, not consecutive.

Abstract

Students will develop their understanding of plate tectonics using hands-on activities, information searches, guided discussion, and content expertise from the teacher or other subject-matter expert.

Materials

• Include a variety of materials in your classroom as an invitation to learn and use later to generalize. Some materials include; read-aloud stories, Native stories, personal stories, news articles, slides and illustrations of earthquakes and volcanoes, and so on.
• The Alaska Resources Kit: Minerals & Energy (AMEREF); Module B, Alaska’s Geology; available from Alaska Department of Education
• Perfume, ammonia, or other volatile, odorous substances
• Hot plate or other means to create hot water
• Clear plastic shoe box, glass tank, aquarium, or clear glass bread pan
• Ice, food dye, small paper cup, masking tape, water source
• Apple for Scale Model Activity
• Media resources: USGS ’64 quake or other geohazard slides, photos, books, Internet, CD-ROM
• Craft materials to use in student models

Activities

Ongoing Background Student Activity

From week 1 through week 30 of the school year, record and map earthquake and volcano occurrence data on individual student maps and a large classroom map.

Gear-up

Move all students to one side of the classroom. Blindfold them. Open a bottle of perfume, ammonia or sufficiently odorous substance on the opposite side of the classroom. Measure the time it takes the odor to reach the students. Repeat the experiment. This time put the odor-causing substance on a hot plate. Ask students to speculate how the odor traveled from the container across the room to their location. Describe kinetic-molecular theory and relate it to the odor demonstration. Students draw a magnified molecular view of the odor demonstration using cartoon-type molecular characters. Show students pictures, tell stories, ask if they have experienced earthquakes. Ask students to speculate how the odor demonstration relates to earthquakes.

Embedded Assessment

The demonstration, discussion, drawing and speculation are part of embedded pre-assessments to determine student understanding, previous learning, and possible misconceptions.

1

Discuss in small-groups what students know or think they know about the earth’s interior structure. Elicit questions about those topics students want to know more about. Ask students how an apple is similar to the earth. Use the apple as a starting point to discuss the structure of the earth’s interior. Cut an apple in half and use it to refer to the core, layers, and crust of the earth. (See AMEREF Module B for graphic. Similar graphics can be found in texts, and the FEMA Earthquake Book.)

2

Students investigate convection currents by using a heat sink (cup of ice) or heat source (container of hot water on hot plate) to observe movement of dye in water. This activity may be modified by floating “continent cut-outs” on the water surface. (See AMEREF Module B.)

Embedded Assessment: Students draw a diagram to show vertical and horizontal views of convection currents. Use the molecular cartoon characters created during Gear-Up activities to explain what causes convection currents.

3

Students use a world map as a discussion reference to discover possible geographic land matches such as the Atlantic coasts of South America and Africa. Put together a jigsaw puzzle that illustrates global plate boundaries. (AMEREF Module B Plate Tectonic Puzzle.)

4

Collect and share information about the effects of earth’s crustal plate movements. (Sources include: materials from United States Geological Survey (USGS), slides, magazine pictures, newspaper, Web search, stories from Elders, and so on). Use student-generated information as well as information from subject-matter experts (teacher, USGS personnel and so on) to tie together the concept of convection as it relates to interior earth movements, and the large-scale surface effects of plate movements.

Embedded Assessment

Students use words or words and pictures to explain how convection currents cause large-scale movements on the earth’s surface

 

Expanded Sample Assessment Idea

Students design and create a model that shows the relationship between convection currents within the earth’s mantle, large-scale motions of the earth’s interior, and subsequent effects on the earth’s surface.

Procedure

Students will:

1. Work in small groups to decide the format for their model (for example, drawing, flip book, diorama, cut-away sphere, computer graphic, computer simulation, or video) that will demonstrate the relationship between interior motion and surface changes of the earth.
2. Choose the type of surface change their model will simulate.
3. Design and construct their model.
4. Make a formal presentation to the class that demonstrates the relationship between convention currents in the mantle, large-scale motions of the earth’s interior, and subsequent surface changes.
5. Discuss how different large-scale motions of the earth’s interior produce different landforms on the earth’s surface.

Reflection and Revision

Use the models as a reference for discussion about landform grouping around the earth. Why do volcanic mountains appear to form in clusters?

Level of Performance

Student may attempt to construct a model, but the work lacks detail, is incomplete, or inaccurate. Student explanation shows evidence of major misconceptions.

Standards Cross-Reference
(Alaska Department of Education & Early Development Standards)

National Science Education Standards

The solid earth is layered with a lithosphere; hot, convecting mantle; and dense, metallic core. (Page 159)

Lithospheric plates on the scales of continents and oceans constantly move at rates of centimeters per year in response to movements in the mantle. Major geological events, such as earthquakes, volcanic eruptions, and mountain building result from these plate motions. (Page 160)

Land forms are the result of a combination of constructive and destructive forces. Constructive forces include crustal deformation, volcanic eruption, and deposition of sediment, while destructive forces include weathering and erosion. (Page 160)

Some changes in the solid earth can be described as the “rock cycle.” Old rocks at the earth’s surface weather, forming sediments that are buried, then compacted, heated, and often recrystallized into new rock. Eventually, those new rocks may be brought to the surface by the forces that drive plate motions, and the rock cycle continues. (Page 160)

Soil consists of weathered rocks and decomposed organic material from dead plants, animals, and bacteria. Soils are often found in layers, with each having a different chemical composition and texture. (Page 160)

Water, which covers the majority of the earth’s surface, circulates through the crust, oceans, and atmosphere in what is known as the “water cycle.” Water evaporates from the earth’s surface, rises and cools as it moves to higher elevations, condenses as rain or snow, and falls to the surface where it collects in lakes, oceans, soil, and in rocks underground. (Page 160)

Water is a solvent. As it passes through the water cycle it dissolves minerals and gases and carries them to the oceans. (Page 160)

Living organisms have played many roles in the earth system, including affecting the composition of the atmosphere, producing some types of rocks, and contributing to the weathering of rocks. (Page 160)

The earth processes we see today, including erosion, movement of lithospheric plates, and changes in atmospheric composition, are similar to those that occurred in the past. Earth history is also influenced by occasional catastrophes, such as the impact of an asteroid or comet. (Page 160)

Benchmarks

The interior of the earth is hot. Heat flow and the movement of material within the earth cause earthquakes and volcanic eruptions and create mountains and ocean basins. Gas and dust from large volcanoes can change the atmosphere. (Page 73)

Some changes in the earth’s surface are abrupt (such as earthquakes and volcanic eruptions) while other changes happen very slowly (such as uplift and wearing down of mountains). The earth’s surface is shaped in part by the motion of water and wind over very long times which act to level mountain ranges. (Page 73)

Sediments of sand and smaller particles (sometimes containing the remains of organisms) are gradually buried and are cemented together by dissolved minerals to form solid rock again. (Page 73)

Sedimentary rock buried deep enough may be reformed by pressure and heat perhaps melting and recrystallizing into different kinds of rock. These reformed rock layers may be forced up again to become land surface and even mountains. Subsequently, this new rock too will erode. Rock bears evidence of the minerals, temperature, and forces that created it. (Page 73)

Thousands of layers of sedimentary rock confirm the long history of the changing surface of the earth and the changing life forms whose remains are found in successive layers. The youngest layers are not always found on top, because of folding, breaking, and uplift of layers. (Page 73)

Although weathered rock is the basic component of soil, the composition and texture of soil and its fertility and resistance to erosion are greatly influenced by plant roots and debris, bacteria, fungi, worms, insects, rodents, and other organisms. (Page 73)

Human activities, such as reducing the amount of forest cover, increasing the amount and variety of chemicals released into the atmosphere, and intensive farming, have changed the earth’s land, oceans, and atmosphere. Some of these changes have decreased the capacity of the environment to support some life forms. (Page 73)