Name ______________________________ Class___________________Date__________________
Skills Practice Lab
DATASHEET FOR LABBOOK
Some Go “Pop,” Some Do Not
Volcanic eruptions range from mild to violent. When volcanoes erupt, the
materials left behind provide information to scientists studying the Earth’s crust.
Mild, or nonexplosive, eruptions produce thin, runny lava that is low in silica.
During nonexplosive eruptions, lava simply flows down the side of the volcano.
Explosive eruptions, on the other hand, do not produce much lava. Instead, the
explosions hurl ash and debris into the air. The materials left behind are light in
color and high in silica. These materials help geologists determine the
composition of the crust underneath the volcanoes.
MATERIALS
• aper, graph (1 sheet)
• pencils (or markers), red, yellow, and orange
• ruler, metric
PROCEDURE
1. Use the map page on the last page of this lab to do this lab activity, or copy the
map onto graph paper. Take care to line the grid up properly.
2. Locate each volcano from the list following “Applying Your Data” by drawing
a circle with a diameter of about 2 mm in the proper location on your copy of
the map. Use the latitude and longitude grids to help you.
3. Review all the eruptions for each volcano. For each explosive eruption, color
the circle red. For each quiet volcano, color the circle yellow. For volcanoes
that have erupted in both ways, color the circle orange.
ANALYZE THE RESULTS
1. According to your map, where are volcanoes that always have nonexplosive
eruptions located?
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2. Where are volcanoes that always erupt explosively located?
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3. Where are volcanoes that erupt in both ways located?
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Some Go “Pop,” Some Do Not continued
4. If volcanoes get their magma from the crust below them, what can you say
about the silica content of Earth’s crust under the oceans?
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5. What is the composition of the crust under the continents? How do we know?
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DRAW CONCLUSIONS
6. What is the source of materials for volcanoes that erupt in both ways? How do
you know?
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7. Do the locations of volcanoes that erupt in both ways make sense, based on
your answers to questions 4 and 5? Explain your answer.
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APPLYING YOUR DATA
Volcanoes are present on other planets. If a planet had only nonexplosive
volcanoes on its surface, what would we be able to infer about the planet? If a
planet had volcanoes that ranged from nonexplosive to explosive, what might that
tell us about the planet?
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Volcanoes
Name ______________________________ Class___________________Date__________________
Some Go “Pop,” Some Do Not continued
Volcano name
Mount St. Helens
Kilauea
Rabaul caldera
Popocatepetl
Soufriere Hills
Long Valley caldera
Okmok
Pavlov
Fernandina
Mount Pinatubo
Volcanic Activity Chart
Location
Description
46°N 122°W
An explosive eruption blew the top off the
mountain. Light-colored ash covered
thousands of square kilometers. Another
eruption sent a lava flow down the
southeast side of the mountain.
19°N 155°W
One small eruption sent a lava flow along
12km of highway.
4°S 152°E
Explosive eruptions have caused
tsunamis and have left 1–2 m of ash on
nearby buildings.
19°N 98°W
During one explosion, Mexico City closed
the airport for 14 hours because huge
columns of ash made it too difficult for
pilots to see. Eruptions from this volcano
have also caused damaging avalanches.
16°N 62°W
Small eruptions have sent lava flows down
the hills. Other explosive eruptions have
sent large columns of ash into the air.
37°N 119°W
Explosive eruptions have sent ash into the
air.
53°N 168°W
Recently, there have been slow lava flows
from this volcano. Twenty-five hundred
years ago, ash and debris exploded from
the top of this volcano.
55°N 161°W
Eruption clouds have been sent 200 m
above the summit. Eruptions have sent
ash columns 10 km into the air.
Occasionally, small eruptions have
caused lava flows.
42°N 12°E
Eruptions have ejected large blocks of
rock from this volcano.
15°N 120°E
Ash and debris from an explosive eruption
destroyed homes, crops, and roads within
52,000 km2 around the volcano.
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Volcanoes
Name ______________________________ Class___________________Date__________________
Some Go “Pop,” Some Do Not continued
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Volcanoes
TEACHER RESOURCES
Skills Practice Lab
DATASHEET FOR LAB BOOK
Some Go “Pop,” Some Do Not
Teacher Notes
TIME REQUIRED
One 45-minute class period
C. John Graves
Monforton Middle School
Bozeman, Montana
LAB RATINGS
Teacher Prep–2
Student Set-Up–1
Concept Level–3
Clean Up–1
MATERIALS
The materials listed on the student page are enough for one student. Students may
wish to use tracing paper in step 1.
PREPARATION NOTES
Students should be aware that volcanoes with a high water and silica content tend
to erupt explosively. They should use this information to analyze the data in this
activity. You may also wish to inform students that, in general, quietly erupting
volcanoes are derived from basaltic magma, and explosively erupting volcanoes
are derived from granitic magma. Remind students that oceanic crust is basaltic
and low in silica, and continental crust is granitic and high in silica.
Students may need some practice finding locations using latitude and
longitude. If necessary, guide them through the steps needed to locate the first
volcano on the chart.
LAB NOTES
In a very simple way, this lab models how the composition of magma can evolve.
For example, basaltic (mafic) magma can evolve into granitic (felsic) magma
through chemical differentiation processes. Scientists often use measurements of
trace elements in the resulting rock to “fingerprint” the source of magma from
which volcanic rocks formed.
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
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Volcanoes