Teacher's Guide and Lessons

About the Lessons

• Illustrated background information
• Two step-by-step, timed activities
• Reproducible Master Sheets for making overhead transparencies or photocopies (in PDF format)
• Reproducible Activity Sheets for your students

There are six lessons. Lesson 1 and Lesson 2 should be taught in sequence. Lesson 6 is probably best suited as a wrap-up. Many of the activities are demonstrations that will help students, particularly elementary-level students, visualize the physical, chemical, geologic, and biologic processes being presented.

The Master Sheets and some Activity Sheets are in PDF format. PDF format reproduces the look of the printed publication and will be better for creating overlay and overhead transparencies. To view and print the PDF version, you must obtain and install the Acrobat® Reader, available at no charge from Adobe Systems.

Lesson 1: Windows Into the Earth

The lithosphere is the Earth's hard, outermost shell that is divided into a mosaic of 16 major slabs, or plates.

The first lesson introduces the nature of volcanoes and volcanic eruptions. In addressing how and where volcanoes occur, students learn that volcanic eruptions are geologic events that take place within the upper part and on the surface of the Earth's lithosphere.

Volcanic eruptions, however, can impact all of the Earth's systems, including the lithosphere itself: Volcanic eruptions create volcanic mountains. A key point is that understanding how and where volcanoes occur helps students understand the dynamic nature of the Earth's geologic processes.

Lesson 2: Creators and Destroyers

This lesson continues to explain how volcanoes are related to the Earth's lithosphere. With a basic understanding of how volcanoes erupt, students focus on the May 18, 1980, eruption of Mount St. Helens. They see how changes to the volcano's shape in the month prior to the eruption reflected changes that were taking place inside of the volcano. They also learn that volcanic eruptions can destroy the landforms they help create. The May 18, 1980, eruption of Mount St. Helens is a dramatic example of both creation and destruction.

Lesson 3: Up in the Air

The atmosphere is the mixture of gases that envelops the Earth.

This lesson explains how volcanoes can affect the atmosphere. Students learn that volcanic eruptions affect places ten to thousands of miles from an eruption site because of the ejection of volcanic rock fragments, gases, and aerosols into the atmosphere. They also discover that volcanoes do not have to erupt to have an effect on the atmosphere. The presence of volcanic mountains, such as the Cascade Range in the Pacific Northwest, continually affect atmospheric conditions, and hence the climate, of the region.

Lesson 4: Fire, Rock, and Water

The hydrosphere and cryosphere are the subsystems that contain the Earth's water. The hydrosphere is the water on the Earth's surface contained in oceans, lakes, rivers, and streams, as well as ground water that circulates within the upper part of the lithosphere. The cryosphere is water on the Earth's surface in its frozen state, such as glaciers; snow; sea, lake, and river ice; and permafrost (permanently frozen ground).

This lesson explains how water from the hydrosphere and cryosphere can combine with volcanic materials from the lithosphere to produce catastrophic mudflows and floods. Students see the relationship between where mudflows and floods are likely to occur and a volcano's topography. They also discover why snow and ice cap many volcanic mountains and that the potential melting of ice and snow adds to the volcanic hazards on these mountains.

Lesson 5: Death and Recovery

The biosphere is the realm of all living things, including humans.

This lesson addresses the effect volcanic eruptions can have on the biosphere—the realm of all living things. Students learn that while the eruption of Mount St. Helens claimed about 60 human lives, the toll on wildlife and plants was incalculable. By interpreting a set of tree rings, students discover that a volcanic eruption can have positive as well as negative effects on plant growth. Finally, students examine the role that eyewitness accounts played in helping scientists reconstruct the events of the May 18, 1980, eruption of Mount St. Helens, reinforcing the importance of first-hand observation as a scientific tool of investigation.

Lesson 6: Volcanoes and People

The final lesson addresses the fact that volcanic eruptions can occur in populated areas. Students discover that people who have lived with volcanoes have attempted to understand the volcano's presence and behavior—using legends and folklore for most of human history. Students see how, today, scientists reconstruct the history of a volcano's eruptions to understand the potential hazards of future eruptions. Students conclude the lesson by creating materials that they could use to explain volcanoes and their hazards to a community living near an active volcano.

A word about map skills

Many of the activities included in these lessons require basic map skills. Students should know how to read simple maps, such as road maps. They also need to understand the following concepts:

• Basic compass directions (north, south, east, and west)
• Using a map scale to determine distance between two points
• Using a map legend, or key, to interpret basic map symbols
• Locating places on the basis of longitude and latitude

The U.S. Geological Survey's teaching packet What Do Maps Show? is an excellent introduction to map reading for upper elementary and junior high school students. You may want to review it before teaching the topographic map skills used in Lessons 2, 4, and 6.

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