CONCEPT: Changes are constantly occurring in and on the earth.
CONTENT OBJECTIVE: 6I2.00 To understand forces on the surface and within the earth which cause it to change
INSTRUCTIONAL OBJECTIVES: The learner will:
2.01 define fold, fault, earthquake, volcano, and erosion.
2.02 describe both slow and fast changes in the earth.
2.03 relate the plates of the earth to earthquakes.
OUTLINE OF CONTENT:
I. Definition of terms
II. Slow changes in the earth
A. Wind erosion
B. Water erosion
C. Ice erosion
D. Chemical erosion
III. Fast changes in the earth
IV. Relationship of the plates of the earth to land forms
TN COMPONENT OF SCIENCE: Process Of Science
To enable students to demonstrate the process of science by posing questions and investigating phenomena through language, methods and instruments of science
1.1 OBSERVING - The senses are used to develop an awareness of an event or object and the properties thereof.
TN STANDARD(S): The learner will understand that:
1.1a Observing is a process used to develop an awareness of the surrounding environment.
BENCHMARK: By incorporating prior knowledge with the process of observations a better understanding of one's environment may develop.
1.1b The human senses and technological instruments are used to gather information from the environment.
BENCHMARK: Scientific investigation is enhanced through the use of technology.
Four to five instructional periods
Three piles of sand, empty glass tank, water, fan, ice block, baking soda, vinegar, clay to make volcano, three different colors of clay to simulate plates, maps of earthquake prone areas, pictures of volcanoes, faults, mountains, and damage from earthquakes
Have you ever seen a mountain or a picture of one? (response) Have you ever seen a picture of the Grand Canyon? (response) We are going to learn about the different forces on the surface of the earth and within the earth that may cause changes on the earth's surface. Knowing about the forces within will help us prepare for sudden changes.
A FOLD is a bend in the rock strata. A FAULT is a crack in the earth's crust. Since a fault is weak, there is usually movement along fault lines. An EARTHQUAKE is a sudden shaking of the earth's crust. A VOLCANO is an opening in the earth's crust through which lava may flow. EROSION is the movement of weathered rock and rock particles by wind or water. (Show models of terms and let students identify.)
Take a sheet of paper and draw a line down the middle of the page from top to bottom. Make dotted lines going from the drawn line out toward the edges of the paper. Give these, dotted lines a slight angle.
Run off enough of these pages for the students. Tell each student to fold the paper lengthwise along the line so that the line is on the outside of the fold.
Before they cut, tell them to put their hands on the paper and try to move the paper. Tell them to cut along dotted lines. Explain that the lines they cut represent rock that has cracked. The two pieces may not move apart. This type of break is called a JOINT or FRACTURE. Sometimes a gap or fissure results when the pieces of rock move apart.
(Demonstrate and ask the students to participate.)
Unfold and place right hand on right side of paper and left hand on left side of paper. Move your hands in opposing directions. If the pieces of rock move sideways, up, or down, a fault occurs which may be small or large. Demonstrate and ask them to participate. Move hands on paper in opposing directions.
(Do activities showing these types of erosion:
1. Using a pile of loose sand and a fan show how wind can cause erosion.
2. Use a pile of loose sand in a glass tank and pour water over it to show how water washes soil away.
3. Demonstrate ice erosion by placing a large block of ice on a pile of sand and let stand until it melts and moves down the pile. Notice marks left in the sand.
4. Chemical erosion can be shown by placing vinegar on a piece of limestone.
Have students record results on all of these activities.)
There are many faults over the earth's surface. Two examples are the New Madrid fault and the San Andreas faults. Since faults are weak areas in the earth's crust, there is usually a lot of movement in these areas. When movement is hindered, energy is stored. When the pieces of rock become "unlocked," stored energy is released, and an earthquake occurs. This is a fast change which can be measured by a seismograph. Some changes are slower such as WIND EROSION, WATER EROSION, ICE EROSION, and CHEMICAL EROSION:
Have any of you ever heard of Mount St. Helen's? What is it? (A volcano) A volcano is formed when extreme heat causes rock to melt (Called magma). This magma pushes up through cracks in the crust of the earth. Then it is called lava. Lava ash and rock may be blown from the volcano. (Show a field trip or video on volcanoes.)
(Construct volcanoes of clay. Use a saucer, bowl, or lid for the base. Students can construct a volcano over the base. After volcano is made pour baking soda and vinegar into the base to demonstrate how lava flows out of a volcano.)
Changes also occur beneath the earth. The earth's crust is made up of six major plates, if the South American and North American are considered as one, plus a number of smaller plates. The plates are a part of the upper mantle as well as being large sections of the earth's crust that slowly move. The plates move at different times, different speeds, and in different directions. As these plates move, they may come together causing the crust to buckle and fold. This action could form chains of mountains over several years. Sometimes one plate may slip under another causing trenches which can eventually form a volcano. If the plates slide against each other, the edges may stick together causing pressure to build up. If it slips suddenly, there will be an earthquake.
Students, I want you to flatten three pieces of clay using a different color for each. The flat pieces of clay are intended to represent layers in the earth's crust. (pause) Stack the layers and press them together. What do you think will happen when you push against opposite sides of the clay? (They will mix to some degree and a lump will start to form in the middle.) Do you think it would be possible for this to happen under the earth? (response, Yes) Do you think mountains and trenches might be formed in this way? (response, Yes)
There are many forces that cause the earth to change. Take out a sheet of paper and a pencil. Draw and label a picture that shows one force that causes a change in the earth's surface. (Place pictures on bulletin board.) Name some places that have been effected by earthquakes, volcanoes, and erosion.
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