Earth Science: Volcanoes Teacher s Guide

Transcription

1 Teacher s Guide Grade Level: 6 8 Curriculum Focus: Earth Science Lesson Duration: 3 class periods Program Description Just beneath Earth s crust lies a ball of molten rock, kept semi-liquid thanks to heat left over from the planet s creation. The crust holds it in place as best it can. When pressure builds up, or tectonic plates shift, or where the crust is thin, volcanoes can erupt. There are 1,511 known volcanoes, 500 of which are active. Every now and then, a new one forms, as happened in 1943 in Paricutin, Mexico. The eruption of Mt. Vesuvius in 79 AD may be the most famous volcanic event, leaving behind perfectly preserved casts of the victims in hardened ash. There are three types of volcanoes composite, shield, and cinder cone. Volcanology is the science of studying volcanoes and predicting eruptions. It s a dangerous job, but with so many lives at stake when an eruption does occur, it s one of great importance. Discussion Questions What is a volcano? Describe in general how a volcano is formed. Why was the eruption of the volcano at Paricutin, Mexico, so important to science? Why does a volcano die? What remnants may be left once a volcano cools off? Why is the 79 AD eruption of Mt. Vesuvius so well known? Define the three types of volcanoes: composite, shield, and cinder cone. Give examples of each. What is volcanology? What methods do volcanologists use to try to predict volcanic eruptions? Lesson Plan Student Objectives Understand the structure of Earth and how cracks in Earth s crust allow magma to erupt onto the surface creating a volcano. Be able to define three types of volcanoes. Create world maps that compare plate tectonics with seismic and volcano activity.

2 Teacher s Guide 2 Materials Computer with Internet access Print resources about volcanoes Overhead projector, 8 1/2 X 11 transparencies, and markers Procedures 1. Volcanoes, earthquakes, and plate tectonics are interrelated. The movement of Earth s crustal plates is what triggers seismic and volcanic activity. An earthquake occurs when tension along a plate boundary becomes too great, the rocks slip releasing energy. When cracks form in the crust, or one plate slips beneath another building up intense pressure and heat, volcanoes can erupt. To understand volcanoes, students need to understand the plate tectonics connection. Creating maps that show Earth s plates, seismic activity, and the world s volcanoes will help make the connection clear. 2. First ask students to review plate tectonic theory and the inner workings of volcanoes. These sites are excellent primers: Wikipedia s Plate Tectonics and Volcano BBC s Science and Nature Hot Topics: Volcanoes and its Bitesize Revision on Volcanoes shtml PBS s The Savage Earth U.S. Geological Survey s This Dynamic Earth Volcano World Check that students have an understanding of plate tectonics and volcanoes by asking: What is the theory of plate tectonics? What do plate tectonics have to do with volcanoes? How can plate movement trigger volcanic eruptions?

3 Teacher s Guide 3 What other natural disasters can plate movement bring on? What other ways can volcanoes form aside from the movement of crustal plates? 3. To reinforce the connection between plate tectonics, earthquakes, and volcanoes, students will create maps that you can view on an overhead projector. Divide the class into three groups. One group will map Earth s tectonic plates; another, the world s volcanoes; and the third, major earthquake zones. So that the maps will match, students can download an outline of the world at Eduplace.com s page Outline Maps ( Click on World: Continents to obtain a PDF file of the map that students can print out on an 8 1/2 X 11 transparency. Each group will need one transparency map. 4. Groups are to use overhead markers to illustrate the information on their maps. The plate tectonics group should illustrate the 10 major plates (according to Wikipedia). The volcano group should plot the locations of volcanic activity with notable volcanoes marked. The earthquake group should mark major earthquake zones and fault lines. These Web sites will help students in their map making: Maps of the World s World Map of Volcanoes and Major Earthquakes of the World PBS s Savage Earth site shows a map of both earthquakes and major tectonic plates. Smithsonian Institution s Global Volcanism Program page Volcanoes of the World Wikipedia s Earthquake Hotspot and Plate Tectonics 5. Once the maps are complete, put the plate tectonics transparency on the overhead projector. Next place the earthquake transparency over the plate map. Students should be able to see that areas of seismic activity follow the edges of crustal plates. Finally, overlay the volcano transparency on top of the plate map. Again, volcanic activity appears along plate boundaries, with some notable exceptions. Ask students why some volcanically active areas do not align with plate edges. The answer is that these volcanoes are on hot spots: areas where Earth s crust is especially thin or where mantle temperatures are exceptionally hot and magma breaks through.

4 Teacher s Guide 4 Assessment Use the following three-point rubric to evaluate students' work during this lesson. Vocabulary 3 points: Students were highly engaged in class discussions; conducted a thorough review of plate tectonics and volcanoes and answered review questions accurately; created an accurate and complete map. 2 points: Students participated in class discussions; conducted a review of plate tectonics and volcanoes and answered most review questions accurately; created an adequate map. 1 point: Students participated minimally in class discussions; conducted a cursory review of plate tectonics and volcanoes and answered few of the review questions accurately; created an incomplete or inaccurate map. cinder cone Definition: A type of volcano that ejects mainly rock, which builds up around the vent Context: Cinder cone volcanoes, such as Arizona s Sunset Crater, are much smaller than composite volcanoes. composite volcano Definition: A type of volcano that ejects lava, as well as ash and rock, to form a tall cone. Also called a stratovolcano. Context: Layers of lava, rock, and ash make up the cone of a composite volcano such as Mt. Vesuvius. hot spot Definition: An area of volcanic activity where Earth s crust is thin or where areas of exceptionally hot mantle exist Context: The Hawaiian Islands formed over a hot spot. lava Definition: Molten rock that has erupted onto Earth s surface Context: Lava can eventually harden into rock and create new landforms. magma Definition: Molten rock beneath Earth s surface Context: Magma collects in chambers beneath Earth s surface; should pressure rise enough, it may break through the surface in a volcanic eruption.

5 Teacher s Guide 5 plate tectonics Definition: Scientific theory that Earth s crust is made up of large plates that fit together like puzzle pieces and float on Earth s mantle Context: Plate tectonics shows that movement of crustal plates can trigger volcanic eruptions. pyroclastic flow Definition: Hot ash, gas, and rock that erupts from a volcano and rapidly descends the mountain Context: The pyroclastic flow from the eruption of Mt. Vesuvius proved deadly to the inhabitants of Pompeii and Herculanium. Ring of Fire Definition: An area of volcanic activity that borders much of the Pacific Ocean Context: The Ring of Fire roughly follows the edges of the Pacific tectonic plate. shield volcano Definition: A type of volcano that ejects large flows of lava that spread out to form a wide, shield-shaped mountain Context: Hawaii s Mona Loa is the world s largest shield volcano. volcanology Definition: The scientific study of volcanoes Context: A chief aim of volcanology is to predict eruptions. Academic Standards National Academy of Sciences The National Science Education Standards provide guidelines for teaching science as well as a coherent vision of what it means to be scientifically literate for students in grades K 12. To view the standards, visit this Web site: This lesson plan addresses the following national standards: Earth and Space Science: Structure of the Earth system Mid-continent Research for Education and Learning (McREL) McREL's Content Knowledge: A Compendium of Standards and Benchmarks for K 12 Education addresses 14 content areas. To view the standards and benchmarks, visit This lesson plan addresses the following national standards: Science: Earth and Space Sciences Understands Earth s composition and structure Geography: The world in spatial terms; Physical systems

6 Teacher s Guide 6 Language Arts: Viewing Uses viewing skills and strategies to understand and interpret visual media; Reading Uses reading skills and strategies to understand and interpret a variety of informational texts Support Materials Develop custom worksheets, educational puzzles, online quizzes, and more with the free teaching tools offered on the Discoveryschool.com Web site. Create and print support materials, or save them to a Custom Classroom account for future use. To learn more, visit Also find these Discovery lesson plans devoted to volcanoes: Understanding Volcanoes Volcano!