GRADE: Third

CONTENT STANDARDS: Earth and Space Science

CONTENT TOPIC: Geology/Earth Structure

CONCEPT: Rocks and soil move through a continuous cycle.

CONTENT OBJECTIVE: 3L4.00 To understand factors which cause changes in the earth's surface

INSTRUCTIONAL OBJECTIVES: The learner will:

4.01 identify various types of landforms of the United States.
4.02 discuss earth movements that produce geologic structures and landforms.
4.03 define cycle as it relates to rocks and soil.
4.04 demonstrate the processes forming sedimentary, metamorphic, and igneous.
4.05 predict the changes that a rock may undergo in the rock cycle.
4.06 explain how rocks are formed and are related, using the rock cycle.

I. Landforms in the United States
A. Plateaus
B. Plains
C. Mountains
II. Earth movements
A. Earthquakes
B. Volcanoes
III. The rock cycle
A. Igneous
B. Sedimentary
C. Metamorphic

TN COMPONENT OF SCIENCE: Unifying Concepts of Science

TN GOAL:

To enable students to acquire scientific knowledge by applying concepts, theories, principles and laws from life/environmental, physical, and earth/space science.

2.1 SCALE AND MODEL - The development of models provides a conceptual bridge between the concrete and the abstract, while the use of scales allows for a comparison of differences in magnitude between the model and the desired form.

2.1a A model is a representation used to simplify complex phenomena.

BENCHMARK Models are developed to represent structures or concepts. These models may be manipulated for simplified analysis of complex ideas.

2.1b Different models can be used to represent the same thing. The kind of model used and its complexity depends on the purpose.

BENCHMARK: Models allow us to make inferences about real world processes and events.

TIME REQUIRED:

Three instructional periods

MATERIALS:

Books, pictures, filmstrips of rocks and land forms included in the outline

Everyone stand beside your desk. When I say "go," everyone shake your whole body. (Let them shake for 15 seconds) Sit down. Today we are going to learn to identify some landforms in the United States. We will also learn that earthquakes are sudden movements of the earth's crust and that volcanoes are openings in the earth's crust through which molten rock escapes.

(Have pictures, filmstrips, books, and displays of rocks, landforms, and volcanoes.) (compare the Earth to an apple. Cut an apple in half vertically. The skin represents the crust, the large meaty part the mantle, and the inner part the core. The earth has three layers, a central core; a thick, hot mantle; and a thin crust. According to the theory of plate tectonics, the earth's crust is composed of a number of moving plates.)

Plateaus are land formations on the earth's surface which are high, similar to mountains, but broad and flat. They are usually inland, but if they reach the coast they often end in a bluff.

Plains are usually flat areas on the earth's surface which are low in elevation. Plains are usually constructed by deposits of soil by oceans near the coast or by water and wind near the interior of the United States.

The crystal plates, we discussed earlier, can collide, move apart, and slip past one another. Mountain building, earthquakes, and volcanoes occur where plates meet. When two plates collide, rocks can be folded up to form folded mountains. Rocks can also be pushed up due to the movement associated with a fault, thus forming mountains along the edge of a fault. How would you describe the area where we live? (response)

Do you recall the three types of rocks which we have discussed before? (Igneous, metamorphic, and sedimentary) I'm glad you could recall them. Now, let's discuss an interesting characteristic common to these types of rocks. The characteristic is that rocks are continually changing from one kind to another. This process is called the rock cycle. An example of the rock cycle would be the formation of sedimentary rocks from sediments which have become cemented together. If the sedimentary rocks are now deep under the surface of the earth, they may be acted upon by high pressures and temperatures to form metamorphic rocks. Even higher pressures and temperatures may cause these metamorphic rocks to melt and harden as igneous rocks. The igneous rocks could then be eroded to form sediments and eventually sedimentary rocks. The process may take many years to make a complete cycle.

1. Have students make a list of unusual landforms they have seen or know about.

2. Show photo of eruption of a volcano that has streams of hot lava pouring out. Ask students these questions:) Where do you think the lava is coming from? (response) What does the lava tell you about the interior of the earth? (response) Why are volcanoes located where they are? How do volcanoes change the earth? (response)

3. Diagram the cycle which the different rocks pass through as they are acted upon by temperature changes, moisture, etc.)

(Go over the list of landforms students made in active participation. Discuss these lists. Have groups of students research these landforms and report their findings to the class.)

Classroom Connector Two

MATERIALS:

Crayon shavings (variety of colors), crayon sharpener, aluminum foil, 2 pieces of wood (approx. 10 cm long), a vise or hammer, heat source (hot plate is best), tongs, aluminum pie tin, water, sand, ice water, and goggles

Show the student several bags of sediment. Ask them if they could be used to form rocks? Show the students samples of sedimentary (sandstones, conglomerates), metamorphic (gneiss, marble) and igneous rocks (granite, obsidian). Ask them to compare the sediments to the rocks. Could the sediments form rocks? Ask them to observe each type and not the properties. How do the rocks differ? How are they alike? Ask them to hypothesize how each is formed? Could one rock change into another type? How are crayons like rocks and the rock cycle? How do they differ?

Do you recall the three types of rocks which we have discussed before? (Igneous, metamorphic, and sedimentary) I'm glad you could recall them. Now, let's discuss an interesting characteristic common to these types of rocks. The characteristic is that rocks are continually changing from one kind to another. This process is called the rock cycle. An example of the rock cycle would be the formation of sedimentary rocks from sediments which have become cemented together. If the sedimentary rocks are now deep under the surface of the earth, they may be acted upon by high pressures and temperatures to form metamorphic rocks. Even higher pressures and temperatures may cause these metamorphic rocks to melt and harden as igneous rocks. The igneous rocks could then be eroded to form sediments and eventually sedimentary rocks. The process may take many years to make a complete cycle.

1. Using the crayon sharpener prepare enough crayon shavings using a variety of different colors to cover a 5 cm by 5 cm area. The shavings should be 1 cm to 2 cm deep. Ask the students to what process does the shaving of the crayons represent? (mechanical weathering of rocks) What do the crayon shavings represent? (sediments) What would have to happen to the crayons in order to reform a crayon? (must be pressed together and possibly heated) What must happen to sediments in order to form a rock? (They must undergo pressure and heat.)

2. Place the crayon shavings in 2 pieces of heavy duty aluminum foil. Fold the aluminum foil to make a packet holding the shavings. Then place the aluminum foil packet of crayon shavings between two boards and place them between a vise and tighten the vise. (If a vise is not available use a hammer and with the packet of crayon shavings between the boards, hammer on the board to flatten the packet.) What does the vise or hammer represent? (Pressure being applied to the sediments)

3. Open the aluminum foil and examine the crayon "sediment." Describe the crayon shavings. (The crayon shavings are packed and stick together. Instead of shavings, the crayons stick together in one piece. The piece crumbles easily.) How is this like sedimentary rocks. (Both are made of particles/sediments which under pressure formed one piece of rock. Particles/sediments break off easily when it is rubbed or broken.) How do the crayon sedimentary rocks differ from sedimentary rocks? (Sedimentary rocks are formed from sediments over a very long period of time and greater pressure is needed than a hammer or a vise. Sedimentary rocks can also be formed by cementation and precipitation.)

4. Rewrap the crayon "sedimentary rocks" and place them between the two boards in a vise. Apply pressure again. (or use a hammer if a vise is not available.) Remove from the vise and examine the crayons again. Describe the results. (The crayon shavings are more compacted and appear to be arranged in rows. They do not crumble or break as easily as in step 3. What is the effect of the additional pressure? (The shavings/sediments are more difficult to break and separate.) Before or after applying pressure, the packet of shavings might be warmed slightly in addition to having pressure applied. Compare the crayon rock to a metamorphic rock. (Both are more difficult to break than the sedimentary rocks, the sediments are more compacted, the sediments are arranged in bands, some are melted.)

5. Rewrap the "crayon rock" and place the foil packet on a heat source. After heating the packet for several minutes, use tongs to remove the packet from the heat source. Allow the packet to cool before opening. Describe the "crayon rock." (The individual sediments are no longer recognizable, they have all melted forming a completely new rock with new properties was formed. The sediments forming it are not recognizable.) How does it differ from the sedimentary and metamorphic rocks?

6. How could you form sediments from the igneous or metamorphic rocks?

Relate what happened to the crayons to the rock cycle. Compare and contrast the crayon rock cycle to rock cycle.

1. Change the amount of pressure or heat or length of heating used.

2. Repeat the activity using metallic or other crayons.

3. Heat other packets of crayons. When the crayons have melted, pour some into ice water, room temperature water and sand or cover with sand. Note the differences.

This is the time this file has been accessed since 05/18/97.

The University of Tennessee at Martin is not responsible for the information or views expressed here.

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