Abstract
In this lesson, students will model lava flows and their effect on volcano formation and model two additional means by which mountains can form.

Purpose – Exploration of volcano and mountain formation and explanation of where different types appear and why.

Objectives
Students will be able to:
1. Describe two types of mountain formation that are not directly associated with collision boundaries.
2. Describe how lava flow affects volcano formation.
3. Explain, in a group discussion, that detailed observation of rocks, minerals and rock layers are necessary to identify the processes that form some mountains and volcanoes.

National Science Education Standard:

CONTENT STANDARD D – Earth and Space Science
ENERGY IN THE EARTH SYSTEM
• Earth systems have internal and external sources of energy, both of which create heat. The sun is the major external source of energy. Two primary sources of internal energy are the decay of radioactive isotopes and the gravitational energy from the earth's original formation.
• The outward transfer of earth's internal heat drives convection circulation in the mantle that propels the plates comprising earth's surface across the face of the globe.

THE ORIGIN AND EVOLUTION OF THE EARTH SYSTEM
• Interactions among the solid earth, the oceans, the atmosphere, and organisms have resulted in the ongoing evolution of the earth system. We can observe some changes such as earthquakes and volcanic eruptions on a human time scale, but many processes such as mountain building and plate movements take place over hundreds of millions of years.

Teacher Background
Earth Science is not always straightforward. Although most volcanoes are formed at subduction zones and form volcanic mountains on land and islands in the sea, this is not always the case. Nor do all volcanoes look alike. Some volcanoes are formed over “hot spots.” These are places where the magma in the mantle spurts upward, breaking through the crust. Volcanoes also vary their shape depending upon the material that is extruded from them. High viscosity magma, or ash eruptions result in the formation of strato-volcanoes also known as cinder cones. Low viscosity magma that pours out of the volcano over a great area results in the formation of shield volcanoes.

Mountains also vary. Many very large, tall mountains ranges are the result of two continental plates colliding with each other; however there are other ranges that are the result of faulting in the earth. Parts of the plates are uplifted and form mountain ranges.

Related and Resource Websites

When Continents Collide
http://www.clearlight.com/~mhieb/WVFossils/collision.html

Types of Volcanoes http://web.archive.org/web/20040604204436/http://www.ssanpete.k12.ut.us/EMS/staff/Staff/Bishop/Bishop-7/dynearth/volcano3.htm

Violent Eruptions
http://web.archive.org/web/20040519140646/http://www.ssanpete.k12.ut.us/EMS/staff/Staff/Bishop/Bishop-7/dynearth/volcano2.htm

Activity

Day One – Mountains
1. Have students stretch clay into rectangles and arrange in layers of alternating colors. What do these layers represent? [Layers of rock in the Earth]

2. Have students place the wooden blocks at the ends of the clay and push them together very slowly and observe what happens. They should record their observations in the science notebooks. Discuss what this model represents. [Mountain formations as continents collide. Students should note that layers are folded on top of each other].

3. Tell students that the continental crust isn’t perfect; there are cracks, or faults in the crust that can run in many directions. Sometimes these faults are responsible for mountain formation.

4. Have students observe carefully as you model the two types of mountain formation by faulting (see the handout) and record their observation in their science notebooks. Where are the mountains forming? Where are the valleys? Do mountains always push up? [No] How could a geologist tell what process formed a specific mountain range? [Look at the rock layers – If students don’t understand this question you might rephrase it to ask, “How can a geologist use rock layers to tell how a mountain range formed?” Students should see that in normal faulting the layers are still parallel, but with uplift, the layers are now tilted.]

5. Closure - Finally, have students return to their maps from yesterday. Ask them, which mountains are not obviously associated with collision boundaries made by normal faulting (fault model #1)? Which are made by uplifting (fault model #2)? [You can’t tell unless you go and survey the rock layers]

Day Two – Volcanoes
1. Tell students that today they will be investigating differences in volcanoes. What do they think differentiates types of volcanoes?

2. Have students take 1 tablespoon of molasses and pour it onto a plate. Using a stopwatch, time how long it takes for the liquid to stop flowing. Repeat procedures with: liquid dish soap, shampoo, and vinegar. Remind students to record observations in an organized data table.

3. Repeat step #2, but add a teaspoon of sand to each tablespoon of liquid. Again, remind students to record data in an organized data table.

4. What do the liquids represent? [Lava] Now what do students believe differentiates volcanoes? [Type of lava] Does the same type of lava always erupt from the same volcano? [No] Which type of lava probably is most violent and causes the most damage?

5. Show students pictures of strato-volcanoes and shield volcanoes. Ask them which type of lava most likely formed each type of volcano. [Low viscosity lavas are found in Hawaii and Iceland. They are usually not very violent. High viscosity lavas often erupt violently and with little, to no lava at all. They can throw “pyroclasts” (literally fire chunks) into the air. Lava that has a lot of silica, a mineral in glass and in most sand, is associated with high viscosity lava and results in violent eruptions.] Do students believe there are only two types of volcanoes? [There are variations; composite volcanoes are formed when a volcano erupts both types of lava at different times.]

6. We saw on the maps a few days ago that not all volcanoes are on plate boundaries. How can you explain their formation? [There are places that the magma comes up through weak areas in the crust, called hot spots. These can form volcanoes if the crust is weak or thin enough. In some places the magma rises up enough to heat the surface and affect the rocks nearby. Hawaii is an example of a hot spot that has broken through. Hot Springs are places where the magma has come close, and heats the area, but does not break through.]

7. Closure - Finally, have students return to their maps from yesterday. Ask them, which volcanoes are shield volcanoes and which are strato-volcanoes? [You can’t tell unless you go and survey the mineral composition] Which volcanoes are from subduction zones and which are hot-spots?

Closure
See each at the end of each day’s lesson

Embedded Assessment
Have students correctly described how mountains can be formed? Can they describe how the type of lava influences the type of volcano that results?

Embedded Assessment

The Community Outreach and Education Program is part of the Southwest Environmental Health Sciences Center: an NIEHS Award

Supported by NIEHS grant # ES06694