Plate Tectonic - Volcanoes (4)
Pre Lab 

   
OBJECTIVES:
  • Comparing different structures of volcanoes.
  • Learning that a volcano can be active, sleeping (dormant), or extinct.
VOCABULARY:
  • active
  • ash
  • cinder
  • composite
  • dormant
  • extinct
  • lava
  • pyroclastic
  • shield
MATERIALS:

Students make a paper model of a composite volcano.

 


A lava fountain eruption in Hawaii

BACKGROUND:

Children are fascinated with the spectacular volcanic eruptions that occur throughout the world. Volcanoes are very important for interpreting what is occurring within the outer portion of the Earth. In addition, as the new Earth developed 4.5 billions years ago, volcanoes released steam, which later became one of the major sources of water on this planet. Volcanoes produce volcanic rocks (igneous rocks) that have built the surface of the Earth. In the theory of Plate Tectonics, most volcanoes are produced where two lithospheric plates (the outer skin of the earth) either diverge (move away from each other) or converge (come together, usually with subduction).

Volcanoes have many different shapes, and can be composed of different types of volcanic rock. Throughout the Plate Tectonic Cycle we will use a simplified volcano shape classification based on the types of materials that compose volcano. Other resources may describe other types of classifications. We distinguish three shapes of volcanoes. First, a shield volcano is composed of lava. The name shield describes the low, broad structure of the volcano, like an inverted shield. The Hawaiian volcanoes are shield volcanoes. Second, a cinder cone is a steeper structure and is composed of cinders (or finely pulverized rock) that were explosively erupted from the volcano. Third, a composite volcano is composed of mixed layers of ash and lava. Composite volcanoes are frequently much higher than shield volcanoes, but not as steep as cinder cones. Mt. Shasta in California, and Mt. Fuji in Japan are examples of composite volcanoes.

PROCEDURE:

  1. Introduce your students to the Plate Tectonic Cycle, by telling them that the outer part of the Earth, its skin, is composed of lithospheric plates of rock. Explain that these plates move, and it is this movement that causes earthquakes and volcanoes. Tell them that this unit will show students the different kinds of volcanoes.  You may want to use selected pictures from Volcano (slideshow). 
      

  2. Draw the diagrams below on the board. Explain the differences among the three types of volcanoes. Instruct the students decide which type of volcano is shown on their worksheets. The volcano model, produced by the U.S. Geological Survey, is a composite volcano.

  1. Instruct the students to color the volcano. Have them then cut it out, and fold and paste it together.

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