Middle School Project

One of the small groups of eighth graders consisted of four students who were interested in researching and writing about volcanoes. The students followed these steps in completing the activity:

1. Choose a topic of interest.
2. Listen to an introduction of the KWL strategy.
3. Research the topic in the library and on the Internet.
4. Follow the steps shown on the Web page figure below to craft an essay (samples are shown below the figure).

Samples of Student Writing from the Volcano Project

The students created the following chart, based on the “K” and “W” components of the KWL strategy.

Next, the students summarized their data in an outline for the essay they would write.

The resulting student essay was as follows:

There are four different forms of volcanoes. They are shield volcanoes, cinder cone volcanoes, composite cone volcanoes, and dome volcanoes. A volcano's form depends on the type of lava, the types of lava are basaltic or grantic. The form also depends on whether it is the result of a quiet or explosive eruption.

Shield volcanoes are the types found on the island of Hawaii. They are in the shape of the wide sloping mounds. These volcanoes hold more fluid (basaltic magma) which overflows the craters or breads through vents along the sides of the mound. This creates a widespread buildup of lava. Shield volcanoes hardly ever erupt violently, but the pouring out of the lava covers roadways and farmlands, and has caused villagers to leave their homes.

The Dome volcano is another kind of volcano. Dome volcanoes are highly dangerous and have very thick lava which does not spread out widely. Instead, the lava forms cones shaped like steep sided domes. This type of volcano explodes from the summit and can cause huge forest fires. After an eruption a plug of lava hardens inside of the crater and prevents the gases and steam from escaping.

Another kind of explosive volcano is the Cinder cone volcano. They are called this because their cones are formed almost entirely of ashes and cinders. Cinders are small, jagged pieces of rock. Durring a series of eruptions the ashes and cinders build up to great heights. The magma in the volcanoes is high in silica and often does not move upward through the neck of the volcano until it is blasted out by the pressure of the trapped gases. Quite of ten these volcanoes blow up huge chunks of their own cones and there is little lava flow.

Most of the volcanoes in the world Composite cones or Stratovolcanoes. They are not explosive as the Cinder cone and Dome volcanoes, but they are more active than the Shield volcanoes. Their eruptions are a combination of lava flows from vents or cracks in the sides and explosions from the top of the cone. They are built with both cinders, lava, and ashes in layers. Their cone is more gracefully shaped that the Cinder cone, but not as low as sloping as the Shield cone. Some Stratovolcanoes or Composite cones are located in the U.S. and Japan.

The last type of volcano does not have a cone at all. Volcanoes of this type are lava fields, which are composed of large flows of molten rock. There are many fissures in the ground which these flows come through. You can see lava of this kind at Yellowstone National Park, where geysers and bubbling hot springs are caused by underground magma. Dormant lava fields can be found in the states of Oregon and Washington.

All in all, volcanoes are extremely fascinating to study, yet thet are very dangerous. Hopefully in the future, we will broaden our knowledge of volcanoes, and finally understand these fierce forces of nature.

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Reading Online, www.readingonline.org
Posted May 2001