Plate Tectonic - Volcanoes (K)
Pre Lab 

   
OBJECTIVES:
  • Learning that not all mountains are volcanoes.
  • Dramatizing how volcanoes erupt.
VOCABULARY:
  • lava
  • magma
  • mountain
  • rock
  • volcano
MATERIALS:

Students dramatize how magma and lava form.


Hawaiian lava flow

BACKGROUND:

Children are fascinated with the spectacular volcanic eruptions that occur throughout the world. Volcanoes are very important to interpret the outer portion of the Earth, as well as to the Earth’s history. As the new Earth developed 4.5 billions years ago, volcanoes erupted, emitting not only lava, but steam, and other gases. This steam, through eons of time, was one of the major sources of water on this planet. The volcanic rocks (igneous rocks) produced by volcanoes make up much of the Earth’s surface.

Explaining why volcanoes occur in certain places requires a knowledge of plate tectonics, specifically the three different types of plate boundaries. Essentially, a variety of processes at plate boundaries cause rocks to melt. This molten rock, called magma, moves upward because it is hot and buoyant. It erupts to form volcanoes. Some volcanoes, like the Hawaiian Island chain, are not related to plate tectonics: these volcanoes form over "hotspots", which are sources of magma (molten rock) the have their origin below the plates.

Volcanoes produce volcanic rocks such as lava, which is magma that has cooled on the surface of the Earth. If the magma cooled inside the Earth, it forms what is called plutonic rock. Both plutonic and volcanic rocks are types of igneous rocks. Melted rocks that have hardened are considered igneous rocks.

When magma erupts on the Earth’s surface, it often builds a volcano, which is basically a pile of cooled volcanic rock. Volcanoes may be hill to mountain size. However, not all hills and mountains are volcanoes. Some are tectonic features, constructed by mountain building , which often happens at plate boundaries, just like volcanism. Others are erosional features, leftovers from earlier tectonic mountains.

Volcanoes are impressive to young students. In the eyes of a child, the fire and disaster caused by volcanoes are simply "awesome." This Pre Lab capitalizes on your students’ curiosity by introducing the science of volcanic eruptions.

PROCEDURE:
  1. Discuss and introduce the concept that not all mountains are volcanoes. Show pictures of mountains that are volcanoes and ones that are non volcanic (see pictures below). The Internet also has many wonderful pictures. Here are some recommended websites:
       
    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/
    University of Michigan volcano sites around the world.

    http://vulcan.wr.usgs.gov/home.html
    The US Geological Survey Cascades Volcano Observatory. Excellent information on US volcanoes, as well as plate tectonics and geologic hazards
      
    http://www.norvol.hi.is/
    The volcanoes of Iceland and their eruption histories.
       
    If you have volcanic rocks in your area, discuss them with the students. If you do not know if the mountains are a result of an old volcano, consult your local university's geology department, natural history museum, or email us with your exact location at (msn@msnucleus.org).
      
  2. Explain to the students that volcanoes produce rocks from cooled down melted lava. The melted rock inside the Earth is called magma and when it erupts on the surface it is called lava. Discuss how lava comes from a volcano. Ask the students about their own experiences with volcanoes.
      
  3. Announce that you are going to have them play a game called "Like a Volcano." Have the students lie in a prone position on the floor and imagine that they are magma inside the volcano. Have them pop up or "erupt," mimicking the eruption of lava. Remember magma inside the Earth, lava on its surface. Repeat this activity several times, reiterating that magma is in the Earth, and lava is outside the Earth.
      
  4. You may want to have samples of volcanic rocks in your classroom, but do not use the same samples for the hands-on lab. You can usually get large "lava" rocks (basalt or pumice) by going to a local landscaping supply house, or use samples in the Minerals and Rocks Display Kit.

Volcanoes and Mountains


Mt. Etna - an erupting volcano in Italy

Mt. Lassen - a volcano in California

The Grand Teton Mountains in Wyoming are not volcanoes. 

This mountain in Utah is not volcanic. 

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