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        Students investigate the processes that build volcanoes, the factors that influence different eruption types, and the threats volcanoes pose to their surrounding communities. They use what they have learned to identify physical features and eruption types of several actual volcanic episodes.

        Lesson Summary


        Anyone who has witnessed a volcano erupting needs no further evidence to know that Earth is a dynamic planet. Volcanoes are one of the major mechanisms for creating new crust. They are powerful, breathtaking, and dangerous, and offer scientists an unparalleled glimpse at Earth's interior. Although the processes that form magma are not well understood, volcanoes — and the igneous rocks they produce — can be studied and explained in the context of plate tectonics. In this lesson, students investigate the processes that build volcanoes, the factors that influence different eruption types, and the threats volcanoes pose to their surrounding environments. After exploring these characteristics, students use what they have learned to identify physical features and eruption types in some real-life documented volcanic episodes.


        • Understand what volcanoes are, how they form, and the rocks they create
        • Create a notebook of volcano characteristics
        • Use acquired knowledge to identify several types of modern volcanic eruptions around the world

        Grade Levels: 6-8 , 9-12

        Suggested Time

        Three to four 45-minute class periods, or two 90-minute class periods

        Multimedia Resources

        Use these resources to create a simple assessment or video-based assignment with the Lesson Builder tool on PBS LearningMedia.


        Before the Lesson

        If possible, arrange Internet access for all students to work in pairs.

        Students will learn about volcanoes and then apply their knowledge by 1) exploring the physical characteristics of various types of volcanoes and 2) identifying the types of volcanoes featured in several case studies. In order to complete the lesson's objectives, students should have a basic understanding of plate tectonics, including the different types of plate boundaries.

        The Lesson

        Part I: Understanding Volcanoes

        1. Before beginning the media-based activities, divide the class into small groups (3-5 students each) and distribute a copy of the World Map Without Volcanoes PDF Image to each group. (If copies cannot be made, use a map in a textbook or one in the classroom and distribute removable dot stickers.) Mention that Hawai'i is one place that is well known for its volcanoes. Now ask the groups to list as many other states and countries as they can that have volcanoes. You may want to suggest that they think about major eruptions that have appeared in the news recently, or famous ones that have happened in history (e.g., Vesuvius and Krakatau). Next, have them mark the locations of the volcanoes on their maps. Before moving on, ask the students the following:

        1. Do you see any patterns?
        2. Can you think of any possible explanations for the patterns you see?

        2. Now hand out copies of the World Map With Volcanoes PDF Image marked and have the groups look at both maps. Ask about the distribution of volcanoes, and have students hypothesize why they are where they are and why certain areas are more active than others. If there is time, have the groups share their lists and other findings with the class.

        3. Ask students to explore the Volcanism HTML Interactive and record in their notebooks answers to the questions below. Students will use the recorded information in the case study activity that concludes the lesson plan. As an optional activity, have the students check out the Mountain Maker, Earth Shaker Flash Interactive to review the basics of plate tectonics.

        1. How do volcanoes form?
        2. What are the four primary types of volcanoes? Name and describe each type in detail. Encourage students to sketch the shape of each type and note its plate tectonic setting (i.e., over hot spots, spreading centers, or subduction zones).
        3. Where do volcanoes form?
        4. Rocks are classified by what they are made of and how they form. Igneous rocks always begin as magma. What are the two main types of igneous rocks, and what is the main difference between them? How does each type form into solid rock?

        4. Next, ask students to check out the Volcanic Eruptions and Hazards HTML Interactive and record in their notebooks answers to the following questions:

        1. Will an effusive eruption have more gas and be more dense (viscous) than an explosive flow, or will it be less gaseous and less viscous? How does each type of eruption cause damage?
        2. Which type of eruption appears to be the more hazardous to humans? Explain your answer.
        3. Of the numerous hazards caused by volcanic eruptions, list and describe at least three that cause damage on a local level, and at least one that has global implications.

        5. Now ask the students to look at the dynamic landforms and features in the Anatomy of a Volcano Flash Interactive and Volcanic Features HTML Interactive . Have them write down the following vocabulary list of features and describe each one: lava, tephra, lava lake, vent, fissure, dike, magma, caldera, crater, geyser, spring, `a`a flow, pahoehoe flow, and lava tubes. As an additional, optional activity, ask students to explore the Virtual Lava Tube Flash Interactive and address the following questions using the resource:

        1. How do lava tubes form, and where are they most likely to be found?
        2. What is the difference between how two common cave features -- stalactites and stalagmites -- form in limestone caves and how they form in lava tubes?
        3. Besides stalactites and stalagmites, choose three lava tube features that interest you, and explain how they form.

        Part II: What Can We Learn from Magma and Lava?

        6. Volcanoes vary greatly in terms of the composition and temperature of the magma they produce, and these characteristics affect how they will erupt. Scientists study lava, fresh from Earth's mantle, to learn more about the inner workings of volcanoes. The Lava Sampling on Kilauea Volcano, Hawaiʻi QuickTime Video demonstrates the simple, yet risky, technique one researcher uses to access lava just as it reaches Earth's surface. Show this video to the class, or have them watch it on their own computers, and ask them to answer the following questions in their notebooks:

        1. Why does scientist Michael Garcia refer to the basalt he is walking on as "the youngest real estate on Earth"?
        2. What does viscous mean?
        3. For what scientific reason does Dr. Garcia quickly quench the hot lava with water?
        4. What has careful study of the composition of the lavas from Kilauea and Mauna Loa revealed about their origins and relationship?

        You can continue this line of volcanic study by showing the Dating Lava Flows on Mauna Loa Volcano, Hawaiʻi QuickTime Video , which provides further insight into the Hawaiian volcanoes and describes the effective method one scientist has found of dating prehistoric lava flows.

        Part III: Case Studies — Applying Your Knowledge

        7. Mount Pinatubo
        Ask the students to view the Mount Pinatubo: Predicting a Volcanic Eruption QuickTime Video and the Mount Pinatubo: The Aftermath of a Volcanic Eruption QuickTime Video . Using the notes they have taken during the lesson, have them answer the following questions in their notebooks. Engage them in a class discussion before proceeding to the next case study.

        1. Was the Mount Pinatubo eruption an effusive or explosive eruption?
        2. Based on your observations, what type of volcano is Mount Pinatubo? On what evidence do you base your answer?
        3. Over what type of plate boundary is this volcano located? Is this tectonic setting consistent with your answer to the first question?
        4. Because vulcanologists were able to accurately predict the timing of this eruption, the lives of hundreds of people who evacuated the nearby area were probably saved. What evidence did the scientists observe that prompted them to call for an evacuation?

        8. Tungurahua
        Ask the students to think about what might make predicting a volcanic eruption difficult and what problems might result from inaccurate (false-positive or false-negative) predictions. Have them record their ideas in their notebooks and then explore the Forecasting Volcanic Eruptions HTML Interactive . When they're finished, have them consider their previous notebook entries and ask them to record their answers to the following questions. Engage them in a class discussion before proceeding to the next case study.

        1. What problems did the inaccurate eruption forecast of the Tungurahua volcano cause for the people of Ecuador and what difficulties might this cause for community officials in the future?
        2. What three variables do scientists monitor when attempting to forecast volcanic eruptions?
        3. What are some of the hurdles that vulcanologists face when trying to make accurate eruption forecasts?

        9. Kilauea
        Next, have students view the Plate Tectonics: The Hawaiian Archipelago QuickTime Video and respond to the following questions. Again, engage them in a class discussion before proceeding to the next case study.

        1. Based on your observations of this video and previous videos you have seen, what type of volcanoes are Kilauea and the other Hawaiian volcanoes? On what evidence do you base your answer?
        2. Does Hawai'i experience effusive or explosive eruptions?
        3. Explain Hawai'i's setting in terms of plate boundaries. What makes it so unusual?

        10. Mount St. Helens
        Finally, have students view the Mount St. Helens: Before and After Flash Interactive and respond to the following questions. Discuss their responses.

        1. Describe what is happening throughout the eruption. What kind of material is being ejected by the volcano? Do you see lava? What happens to all of the ash?
        2. Based on your observations, what type of volcano produced this eruption? On what evidence do you base your answer?
        3. Based on the before and after images, identify ways in which both the volcano and surrounding area were changed by the 1980 eruption.
        4. Based on the satellite images, how has the affected area changed in the time since the eruption?
        5. What are some similarities and differences in the destruction caused by effusive and explosive eruptions? What, if anything, was surprising to you about the blowdown, lahar, and pyroclastic flow images?
        6. What factors play a part in the recovery of vegetation (and wildlife) in areas affected by volcanic eruptions?

        Check for Understanding

        Have students discuss the following:

        1. What are the differences between the four types of volcanoes? Is there one distinguishing characteristic, or more than one?
        2. Which types of volcanoes form on divergent plate boundaries? On convergent plate boundaries? What is a hot spot?
        3. Is it possible for scientists to predict when a volcano will erupt so they can call for the evacuation of the area around it? If so, what kind of evidence do the scientists need to make such a prediction?
        4. Describe the hazards that volcanoes present for humans who live near them.

        The Digital Library for Earth System Education ( offers access to additional resources on this topic.


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