A.Uttereyuk!–EarthScience–TechLesson–GuideLite! · read!about!current!volcano!hazard!predictions!and!warnings,earthquake! ... are!wellorganized!with!very!detailed ... incandescent

A. Uttereyuk – Earth Science – Tech Lesson – Guide Lite


Pyroclastic Materials According to the United States Geological Survey (USGS), pyroclastic flows are “high-‐density mixtures of hot, dry rock fragments and hot gases that move away from the vent that erupted them at high speeds. They may result from the explosive eruption of molten or solid rock fragments, or both. They may also result from the non-‐explosive eruption of lava when parts of dome or a thick lava flow collapses down a steep slope…” (http://volcanoes.usgs.gov/hazards/pyroclasticflow/index.php) The pyroclastic materials range in size from very fine dust to large boulders. These materials are very destructive and can affect the land in many ways. Due to the extreme temperatures of volcanoes and pyroclastic materials, they can burn forests, land, and buildings with the extreme temperatures, melt snow and flood rivers, bury towns with debris, and destroy by the impact of landing materials. Objective: In this activity students will gain a better understanding of the types of pyroclastic materials are ejected from volcanoes and their sizes in relation to each other. They will describe the dangers of volcanic eruption and present their findings to the group. Materials: Rocks and dirt of various sizes (less than 2mm to 64mm or more) Rulers Pencils Images of volcanic eruptions and the different types of pyroclastic materials (see

Appendix A) Cards labeled with the types of pyroclastic materials Student note sheets (see Appendix B) Paper Colored Pencils or Crayons Notecards

Engage: Preparation: Have students bring in 5 rocks from around town as homework. They can be different sizes, colors, etc. (Collect extras in case students forget.) The teacher will need to copy Appendix B for each student and to set up stations around the room with paper to put the rocks on top of when sorting them. Action: Do the “before” section of Appendix B as a pre-‐test. Students should look at the list of pyroclastic materials and make educated guesses as to the order from smallest to largest. After all students are finished, the teacher should show appendix A and discuss the sizes of the materials in the pictures. Then the teacher will show


students the labels on the papers at each desk to show the size of the pyroclastic material that will be put on each paper. Students will work to put their 5 rocks into the category where they belong. When finished, discuss each pile and move rocks to the proper pile(s) if necessary.

Now that students are familiar with the particle sizes and the names of them, have them split into small groups of 3 to 4 students. Each student is going to be a “volcano hazard expert” and will research one of the types of pyroclastic materials that come from a volcano. Each group will create a paper that includes the following components: Name of the pyroclastic material, a picture of it with the size written (hand drawn or printed), what problems does it cause for people, buildings, animals, and habitats (aka. why is it dangerous?), what type of volcano does it come from, how does it form, and other characteristics of the pyroclastic material. When they are finished, each group will present their paper to the class and have one representative relay the research about that pyroclastic material in a 2 minute or so presentation. (See Appendix C for the rubric.) As a final activity for the day, students will write on a notecard individually which type of pyroclastic material they think is the most dangerous and give 3 reasons why they feel that way. Explain: To explain more about pyroclastic flow, visit some of these helpful websites with great resources and animations. Geologynet: Pyroclastic Deposits -‐ (http://www.geologynet.com/pyro.htm)

This website has superb descriptions of the types, sizes, and compositions of pyroclastic materials.

CVO Website -‐ (http://vulcan.wr.usgs.gov/Glossary/PyroFlows/description_pyro_flows.html) This website has more definitions of pyroclastic flow with cited sources. It could help you rephrase your definition while still being scientifically accurate.

Pyroclastic Flows and Surges -‐ (http://vulcan.wr.usgs.gov/Glossary/PyroFlows/description_pyro_flows.html)

Less than 2 millimeters

2 to 64 millimeters

Greater than 64 millimeters

> 64 mm and angular


This is a great website with links to watch pyroclastic flows with dates from different volcanoes.

How Volcanoes Work – (http://www.geology.sdsu.edu/how_volcanoes_work/) This website has tons of links and information about pyroclastic flow and volcanoes that are easy to access and well labeled. It is sponsored by NASA and Project ALERT (Augmented Learning Environment and Renewable Teaching) and is user friendly for earth science teachers.

Extend: To learn more about volcanoes in general and how they erupt, see these websites. The Alaska Volcano Observatory (http://avo.alaska.edu/)

Here you can learn more about the monitoring of Alaskan volcanoes from stations in Fairbanks and Anchorage, look at photographs of Alaska volcanoes, read about current volcano hazard predictions and warnings, earthquake recording data, and much more. This website is filled with valuable information about volcanoes.

Kids Fun Science: Pyroclastic Material -‐ (http://www.kids-‐fun-‐science.com/pyroclastic-‐material.html) This website is a kid-‐friendly version with links to other parts of the rock cycle and volcanic activity easy to navigate. It would be good to add a student research element to the lesson.

Mount St. Helens Movies and Animations -‐ (http://vulcan.wr.usgs.gov/Volcanoes/MSH/Images/MSH04/movies_and_animations.html) If you want to show your students clips from Mount St. Helens’ eruption, there are well organized with very detailed descriptions for each video.

Forces of Nature -‐ (http://environment.nationalgeographic.com/environment/natural-‐disasters/forces-‐of-‐nature/) Once you click on “Volcanoes” as the force of nature to learn about, this animated website has great photos and information about volcanoes. There is a digital lab with “Make your own volcano” where you control the amount of gas, silica content, etc to see the eruption simulated. Students will love this! There is also a map with volcanoes and eruption dates labeled, and case studies of those volcanoes with pictures, clips from the eruptions, and lots of information.


Appendix A: Reference sheet of the different pyroclastic materials

ASH -- Very fine-grained fragments (< 2 mm), generally dominated by broken glass shards, but with variable amounts of broken crystal and lithic (rock) fragments.

Courtesy of USGS.

LAPILLI -- Pea- to walnut-size pyroclasts (2 to 64 mm). They often look like cinders. In water-rich eruptions, the accretion of wet ash may form rounded spheres known as accretionary lapilli (left).

Courtesy of USGS.

BOMBS -- Fragments >64 mm. Bombs are ejected as incandescent lava fragments which were semi-molten when airborne, thus inheriting streamlined, aerodynamic shapes. Courtesy of J.P. Lockwood, USGS. BLOCKS-- Fragments >64 mm. Blocks are ejected as solid fragments with angular shapes. Courtesy of J.P. Lockwood, USGS

Source: http://www.geology.sdsu.edu/how_volcanoes_work/Tephra.html


Appendix B: Student Note Sheets BEFORE:

Type of Pyroclastic Material Size Rating (1=smallest to 7=largest)

Fine Ash/Dust Lapilli Ash

Bombs Blocks

Pumice/Scoria

Type of Pyroclastic Material Danger Rating (1=least to 7=most destructive) Fine Ash/Dust

Lapilli Ash

Bombs Blocks

Pumice/Scoria

AFTER:

Type of Pyroclastic Material Size Rating (1=smallest to 7=largest)

Fine Ash/Dust Lapilli Ash

Bombs Blocks

Pumice/Scoria

Type of Pyroclastic Material Danger Rating (1=least to 7=most destructive) Fine Ash/Dust

Lapilli Ash

Bombs Blocks

Pumice/Scoria


Appendix C: Group Paper/Presentation Rubric Assignment components: Name of the pyroclastic material, a picture of it with the size written (hand drawn or printed), what problems does it cause for people, buildings, animals, and habitats (aka. why is it dangerous?), what type of volcano does it come from, how does it form, and other characteristics of the pyroclastic material. When they are finished, each group will present their paper to the class and have one representative relay the research about that pyroclastic material in a 2 minute or so presentation.

Component 3 2 1 Names on paper X Present Not Present

Name of the

material is present

Clear, Easy to find Written but difficult to find

Not Present

Picture Good picture or drawing

X Wrong picture or Not Present

Problems for

people, buildings,

animals, and

habitats explained

Good descriptions of all four.

Good descriptions of at least half of them, or one is missing.

More than one are missing or descriptions are not accurate.

Volcano Type Present X Not Present

How it Forms Present, good clear description

Present but description not complete

Not Present

Presentation Good presentation, Took their time to discuss the key points.

Okay presentation, may have rushed or not talked about the key points.

Did not Present.

Total Points Possible: 20 Team Score: _______ /20 = ________%

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