Plate Tectonic - Volcanoes (5)
Pre Lab 

   
OBJECTIVES:
  • Exploring the rocks produced by volcanoes.
  • Describing the parts of a volcano.
VOCABULARY:
  • andesite
  • basalt
  • igneous
  • obsidian
  • pumice
  • ring of fire
  • scoria
  • volcanic
MATERIALS:

Students search the Internet for information on volcanoes.


Klyuchevskoi (Kamchatka, Russia)

BACKGROUND:

The study of volcanoes begins the unit on plate tectonics. Plate tectonics is a science that investigates the movement of the Earth's crust. It includes the exterior and interior of the Earth. Both volcanoes and earthquakes provide data for plate tectonics.

Magma that feeds volcanoes comes from the upper mantle and lower crust, and not the deep interior of the Earth. Volcanoes were and are important to the development of the Earth. Lava produced the "continents" while the Earth was forming. Volcanoes also produced the water that we have on this Earth, by chemically combining hydrogen and oxygen inside the Earth, to produce steam which was released when the volcanoes erupted.

The interaction of the moving plates at boundaries creates conditions which melt rock. Melted rock is less dense than solid rock, so it will rise and cause an eruption. The model of plate tectonics helps explain why and where we have volcanoes. However, some volcanic action, like the Hawaiian Islands, do not quite fit into the model. Hawaii is in the middle of the Pacific Plate, not at a plate boundary. This and other intraplate volcanoes are probably caused by hotspots, which are magma sources in the Earth’s mantle below the plates. Hotspot magma generation is not fully understood. The restless Earth is not fully understood, so new models on volcanic activity can emerge with new data.

PROCEDURE:
  1. Show the students the layers of the Earth using the physiographic globe, or use pictures in Volcano (slideshow). Point out that the magma that feeds volcanoes comes from the upper mantle and lower crust, and not the deep interior (core) of the Earth. Explain that plate tectonics movements involve the crust and upper mantle, which are collectively called the lithosphere. Students in the fifth grade should have learned about the shapes of volcanoes and their general classification. If they are not familiar with volcanoes review the materials from prior grades.
      
  2. In lab, the students will look at various types of volcanic rocks. Review the vocabulary words with the class, emphasizing that the students will see these rocks in the lab. Remind them that igneous rocks come from volcanoes or from magma that cooled within the outer portion of the Earth. Again, use the physiographic globe to emphasize that magma for volcanoes does not come from the center of the Earth, but only the crust and upper mantle.
      
  3. Review the following diagram and the different types of volcanoes. It is part of the presentation below, or draw it on the board.
    1. VENT
    2. MAGMA CHAMBER
    3. LAVA
    4. PUMICE, SCORIA
    5. OBSIDIAN (OUTSIDE)
    6. BASALT OR ANDESITE (INSIDE THE LAVA FLOW)
        
  4. Instruct the students to conduct a web search on volcanoes to find out more information on their locations; which ones are currently erupting; and how much damage volcanoes do. The web is full of wonderful sites that show the majestic mountains formed by volcanoes. Below are a few sites that could aid your students, but make sure students perform a search to find their own sites.

    http://www.meto.umd.edu/~jose/VOLCANOES/volcpage.html/ 
    This site has good pictures, including a simulated 3-D column of ash erupted out of a volcano.

    http://volcano.und.nodak.edu/vwdocs/current_volcs/current.html/ 
    Information on currently erupting volcanoes around the world, with links to each site.

    http://www.geo.mtu.edu/volcanoes/ 
    Michigan Technological University - volcano sites from around the world.

    http://www.usgs.gov/ 
    The US Geological Survey has many links to volcanic activity.

    http://www.noryol.hi.is/ 
    The volcanoes of Iceland and their eruption histories.

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