Overview
Students use ice cream glaciers and hot wax
lava ows to simulate the interaction of
glaciers and lava ows.
Learner Objectives:
Students will:
●
Recognize that the volcano and its
glaciers co-exist as a dynamic system
●
Identify the types of interactions and
energy transformations, that occur
between glaciers and hot volcanic rocks
●
Identify some types of geologic features
at Mount Rainier that are a product of
glacier-volcano interactions
Setting:
classroom
Timeframe:
50 minutes for demonstration
and discussion. For student groups, add
20–30 minutes for next day observations
and discussions
Materials:
●
Graphic
“Glaciers on Mount Rainier”
●
Graphic
“Columbia Crest Summit”
●
Graphic
“Glacier-Volcano Interactions”
●
Graphic
“Maximum Extent of Glaciers
on Mount Rainier During the Ice Ages”
●
Graphic
“How Lava Ridges are Made”
Grade Level: 6–10
Fire and Ice
Activity last modied: September 5, 2014
●
Graphic
“Glacier Scratches (Striations)
on Lava Rock at Mount Rainier”
●
Graphic
“Volcanic Rocks of Modern
Mount Rainier”
●
Graphic
“Lava flows—Experimental and
Real World Comparisons”
●
Stove or other heat source
●
Candy thermometer
●
Double-boiler pot
●
Disposable stirrer (pencil, paint stirrer,
stick
●
Camera (optional)
Ingredients required for each model:
●
metal cookie tray with sides (1/2 inch
high minimum)
●
cereal bowl
●
wax paper
●
masking tape
●
modeling clay (8 oz per model group;
black illustrates solidified lava well)
●
ice cream (1 quart; vanilla illustrates
glacier ice well)
●
ice cream scoop
●
household wax (one pound; used for
canning, candle making; also called
“Home Canning Wax,” or “Paraffin”)
●
crayons (four different colors
(quality crayons work best; do not use
water soluble crayons)
●
scissors to cut clay strips—for use with
soft clay only (optional)
1
U.S. Department of the Interior
U.S. Geological Survey
General Information Product 19
Living with a Volcano in Your Backyard
-
An Educator's Guide with Emphasis on
Mount Rainier
Prepared in collaboration with the National Park Service
NATIONAL
PARK
SERVICE
Fire and Ice
-
continued . . .
Vocabulary:
Erosion, glacier, ice ages,
lahar, lava, lava flows, pyroclastic flow,
striations, vent, volcano, volcanic eruptions
Skills:
Interpret, infer, demonstrate,
explain, predict, visualize
Benchmarks:
See benchmarks in Introduction.
2
Fire and Ice
-
continued . . .
Teacher Background
Glaciers and Mount Rainier co-exist as a dynamic system
Mount Rainier distinguishes itself among other Cascade volcanoes because of its
widespread high-altitude slopes and extensive snow and ice cover. About 88 square
kilometers (34 square miles) of snow and ice cover the mountain at summer’s end.
Glaciers have covered Mount Rainier over much of the volcano’s 500,000-year
lifespan, creating a dynamic system. The volcano provides high-elevation slopes that
are conducive to glacier formation and glacial erosion. Volcanic eruptions can melt
snow and ice, even while glaciers inuence the movement of lava ows. A general list
of mechanisms of inuence between glaciers and volcanoes is shown in the sidebar. This
information is depicted in graphics “Glaciers on Mount Rainier,” “Columbia Crest
Summit,” and “Glacier-Volcano Interactions.”
Mechanisms of Influence—Glaciers and Volcanoes
3
A Volcano’s Inuences upon its Glaciers
Mount Rainier is an obstacle to moisture-
laden air from the Pacific Ocean. The
air is forced to rise, cool, and drop its
moisture.
Frequent cold temperatures on high-
altitude slopes provide an ideal environment
for snow retention and transformation to
glacier ice.
Extensive slopes of rugged volcanic terrain
trap blowing snow and contribute to snow
retention and glacier formation.
Volcanic eruptions melt snow and ice.
A Glacier’s Inuence upon its Volcano
Rock debris embedded in ice at the bottom
and margins of a glacier mechanically
erodes surrounding rocks.
Glacial meltwater streams remove and
transport loose rock from the mountain.
Glaciers can influence the distribution of
lava flows.
Glaciers provide meltwater for formation
of debris flows and lahars, which alter the
volcano’s landscape.
Fire and Ice
-
continued . . .
Ice-age glaciers envelop Mount Rainier
To understand the extent to which hot volcanic rocks have interacted with surrounding
glaciers, we need to put on our “glacier glasses” and envision landscapes largely buried
by ice. During ice ages that occurred repeatedly between approximately 1.8 million and
11,000 years ago, large ice sheets covered northern Europe and much of Canada and the
northern United States, including the Puget Sound area. Mountain ranges in the western
United States, including the Cascades were mantled by extensive glaciers. Some of the
glaciers on Mount Rainier were hundreds of meters (1,000 feet or more) thick on the
anks of the volcano and almost 1,000 meters (3,000 feet) thick in valleys at the base of
the cone. Mountain glaciers coalesced and owed for 100 kilometers (60 miles). Glacier
ice covered the locations of the present day communities of Ashford, Alder, Greenwater,
and Carbonado. Around 15,000 years ago, these enormous glaciers began to thin and
recede into existing valleys. Their descendents cover much of Mount Rainier today. View
the extents of glaciers then and now in the graphic “Maximum Extent of Glaciers on
Mount Rainier During the Ice Ages.”
Mount Rainier erupted repeatedly while buried by ice-age glaciers
Mount Rainier erupted repeatedly during past ice ages. The co-existence of volcanic and
glacial processes led to a variety of interactions that shaped the mountain in a unique way.
The origins of these features can be understood only when the interactions of the glaciers
and volcanic forces are recognized.
4
When lava meets ice
During times of extensive glaciation, lava poured repeatedly from the summit vent of
Mount Rainier and encountered glaciers. In the contest between lava ows, rock, and ice,
glaciers at rst appear to be less durable. In theory, a lava ow can melt about ten times
its volume of ice, though it rarely does so. We commonly think of lava ows as bullish,
relentless, and unstoppable. However, observations at ice-clad volcanoes around the world
prove that glaciers can survive the onslaught of heat from lava ows. In some situations,
glaciers can exert some control over the movement of lava ows, and as such are the
architects of Mount Rainier. Consider these mechanisms.
◆
Lava ows tumble and disintegrate on steep slopes: Lava that ows over steep
slopes often breaks apart and plunges onto the glacier, where it cools as rock debris.
Sometimes the fragmenting lava ow forms a turbulent avalanche of scorching
hot rock and gas called a pyroclastic ow, which can sweep across the snow and
ice. Incorporation of snow and ice into the pyroclastic ow can cause the ow to
transform into a volcanic mudow (lahar). Lahar layers are found in river valleys
that extend from Mount Rainier.
◆
Ice-age glaciers act as physical and thermal barriers to lava ows: An advancing
lava ow melts downward through thick ice until it contacts bedrock, where it
chills and hardens, conned within the glacier. After the eruption, glacier ice often
ows across the hardened lava ow. By this mechanism, Mount Rainier gains
volume, and retains its glacier cover. Some of these lava ows, now partially
eroded, are visible as ledges on the anks of Mount Rainier.
◆
Thin ice and ice-free regions allow lava ows to travel far: Lava encounters less
resistance in the thin ice and ice-free ridges between thick valley glaciers. The lava
ow’s outer skin cools and hardens, while the interior of the ow remains uid and
travels many kilometers (miles) from the base of the volcano. Over time,
successive stacks of elongated lava ows have built ridges—from the bottom
up—in a pattern that radiates from the cone of Mount Rainier. Paradise Ridge,
Mazama Ridge, Rampart Ridge, and Emerald Ridge are some examples of this
phenomenon. This interaction is depicted in the graphic “How Lava Ridges
are Made.” The phenomenon can happen only when glaciers envelop Mount
Rainier, such as during an ice age.
Fire and Ice
-
continued . . .
5
Fire and Ice
-
continued . . .
More about glaciers
A glacier is a large mass of owing ice formed by the compaction and recrystallization
of snow that has accumulated over a period of years. When snow crystals land atop one
another their fragile edges snap and break. Pressure from overlying snowpack settles the
crystals, squeezes out adjacent air pockets, forces them to liquify and then recrystallize
as ice. By these processes, delicate snow crystals transform into a strong lattice of ice
crystals that has sufcient strength to transform the landscape.
Glaciers as sculptors
Glaciers are well known as sculptors of the landscape, but the true artist is rock debris
encased within the ice. Landslides and rock fall produce rock debris that drops onto the
glacier surface. Winter snow falls bury the rock debris. Snow surrounding this rock debris
transforms to ice. Eventually some of the entrapped rocks touch the valley oor and
walls where they scrape and polish, as with grit in a gem polishing machine. Millennia
of erosion by glaciers are responsible in part for the characteristic U-shaped valleys. See
glacial scratches (striations) depicted in the graphic “Glacial Scratches (Striations) on
Lava Rock at Mount Rainier.”
Present-day glaciers at Mount Rainier
While Ice-Age glaciers have thinned and receded dramatically over the last 15,000 years,
Mount Rainier still hosts one of North America’s largest single peak glacier systems. The
present glaciers consist of approximately 4.4 cubic kilometers (1 cubic mile). For scale,
imagine an ice cream scoop the size of Seattle's Safeco Field sports stadium. Removing
all the perennial (long-lasting) snow and glacier ice from Mount Rainier would require
2,600 stadium-sized scoops! Envision this also as an ice cube one mile on a side. The
volume of perennial snow and glacier ice on Mount Rainier is equivalent to the amount of
ice on all the other Cascade volcanoes combined.
6
Fire and Ice
-
continued . . .
Procedure
Fire and Ice
Students use ice cream glaciers and hot wax to simulate the interaction of ice-age glaciers and
lava ows. They observe results and relate this to actual processes and features at Mount Rainier.
What to do Before Class Begins:
1. Decide whether you will conduct this activity as a demonstration or with student groups.
Student groups will require multiple amounts of items listed in “Materials,” and
additional time for setup. Students build their model, and then make repeated
trips to the source of the molten wax on a stove top or hot plate.
2. A demonstration can be accomplished in less time, but will require you to assemble
the wax papered tray and volcano model, and to break crayons and melt the wax prior
to the beginning of class. If conducting the demonstration with several classes, consider
constructing ice age glaciers with the rst class and adding one or more layers of wax
“lava” with each successive class, followed by examination of the model the next day.
3. Decide whether to assign students with homework that investigates glaciers, ice ages,
and glacier-ice interactions (Procedure Part I number 2) prior to performing the activity.
4. As you prepare for post-activity discussion, keep in mind that no two completed
volcanoes models will be alike. On these models, both ice cream glaciers and the older
clay lava ows can inuence the route of young wax lava ows. Students might
observe that successive pourings of wax cause “stacking” of lava ows, as produced
at Mount Rainier during the ice ages. Remind students that they should make general
observations about melting of ice cream glaciers, the size, shape and overlapping nature
of lava ow layers, and any interactions of wax lava ows with the tray rim. Be
prepared for a variety of results.
7
Fire and Ice
Part I: Preparing Students for the Activity
1. Display the graphic “Glaciers on Mount Rainier” and point out that the glaciers are
large; they show crevasses and are visible in white. Small discontinuous white areas
are snow or ice patches. These do not ow and are not considered glaciers.
2. Instruct students to hypothesize about ways that the volcano and the glaciers
inuence one another. (You might wish to assign this as homework on the day
previous to the volcano model.) Diagram their answers on the classroom
whiteboard. Refer to the “Teacher Background,” and to the graphics “Columbia
Crest Summit,” “Glacier-Volcano Interaction,” and “Glacier Scratches
(Striations) on Lava Rock at Mount Rainier.”
3. Display the graphic “Maximum Extent of Glaciers on Mount Rainier During the
Ice Ages” which illustrates the maximum extent of glaciation during the ice ages
and today. Tell students that the volcano model in the activity represents glaciation
during the last ice age; some older ice ages had even more extensive glaciers.
Part II: Setup of the Volcano and Glacier Model
1. Begin preparation of the volcano model by
covering a tray and cereal bowl with wax
paper.
Use masking tape to hold paper in place.
Less surface area exposed to hot wax means
reduced time spent on messy cleanup.
2. Turn bowl upside down on the tray as a
volcano model.
The inverted bowl will represent the existing
volcano that formed previously by the
accumulation of volcanic rocks. Newer lava
ows made of wax will be poured over the top
of it.
Fire and Ice
-
continued . . .
8
3. Make clay strips that represent previous
accumulations of lava rock as ridges that radiate
from the volcano.
Remove clay from its container and shape into strips
1.5 centimeters (0.5 inch thick) and approximately 13
to 17 cm (5 to 8 inches) in length. Drape clay strips
over the volcano model in a variety of congurations.
Some strips should be longer than others; some
should diverge and others converge at their toes.
Cover the top of the bowl completely with a thin
layer of clay. Optionally, obtain additional clay in
other colors, and stack multiple lava layers on top
of each other. Remind students that each strip
represents accumulations of volcanic rock from
previous lava ows.
4. Cover volcano model with vanilla ice cream to
represent enormous ice-age glaciers.
Scoop the ice cream onto the volcano model.
Press it tightly against the clay and the waxed paper
to reduce leakage. Stuff the ice cream into the deeper
spaces between the clay strips to represent thick
glaciers. Cover the clay strips (existing lava ows)
with a thin layer approximately 1 centimeter,
(approximately 1/3 inch) of ice cream. Alternatively,
leave some of the clay strips exposed so that the
students observe how existing ridges can inuence
lava ow speed and direction.
5. Melt the wax.
Obtain a stove top heat source and
double-boiler system. Place 454 grams (1 pound)
of wax into the double-boiler carefully and melt
it, following all product safety instructions. Monitor
temperature with a candy thermometer. Temperature
should never exceed 90 degrees Celsius (200 degrees
Farenheit). Wax takes about 15 minutes to melt, but
remains uid for about 45 minutes after removal from
heat. Cooler wax makes thicker, more obvious wax
lava ows.
Fire and Ice
-
continued . . .
9
6. Color the wax lava with crayons.
Remove the paper wrappers from 5 or 6 different
colored non-water soluble crayons and break each
crayon into ngernail-sized pieces. Melt one
colored crayon for each pouring of a wax lava ow,
starting with the crayon lightest in color, and
progressing to darker colors with each new
lava ow (example: clear, orange, red, purple,
black). With this method, you need melt only one
pot of wax to obtain multiple colors of lava ows.
There is no need to subdivide the melted wax into
separate containers.
Part III: Fire And Ice Simulation
1. To be sure that students understand the volcano
model, ask them the following questions:
a. What does the bowl represent?
b. What do the clay strips represent?
c. What do the areas of ice cream represent?
d. What does the wax represent?
e. Describe the appearance of the landscape
beneath the glaciers.
2. Ask students to hypothesize about what happens
when hot lava and glacier ice interact. What will
happen to the glaciers? To the lava ows?
3. Add half of a colored crayon to the melting wax.
Point out to students that each colored wax
batch represent a new series of lava ows. Slowly
pour approximately one-fth of the melted colored
wax over the summit area and upper slopes of the
volcano model. Allow the wax to cool and solidify
for a number of minutes. In the meantime, add the
next color crayon to the wax in the pot and allow
several minutes for melting. This also provides
valuable time for student observations and
discussion of glacier-lava ow interactions.
Fire and Ice
-
continued . . .
10
4. Instruct student to observe where the lava
travels faster.
Where does the wax lava travel the farthest?
Where does the wax lava pool? Do students
observe melting of the ice cream glaciers? How
does the lava interact with the walls of the tray?
5. Repeat the pouring of wax lava ows and
student observations until all wax has been
poured.
Use cooling times for discussion of energy
transformation that occur when hot lava meets
glacier ice.
6. Instruct students to make additional
observations and to relate them to an actual
volcano.
For example, students might note that melting of
the ice cream represents melting of glaciers; wax
lava ows travel fastest on steep slopes and they
form pools and solidify at the base of the volcano;
wax lava solidies against tray walls as real lava
ows would pool against valley walls. Students
might note that wax lava ows that travel off the
volcanic cone, and over glaciers are thin and
breakable.
Fire and Ice
-
continued . . .
11
Fire and Ice
-
continued . . .
Part IV: Explore Lava Flows at Mount Rainier
1. Review the graphic “How Lava Ridges are Made” with the students. Was this
process of ridge formation one of the processes noted in the “Fire and Ice”
demonstration?
2. Look at the “Volcanic Rocks of Modern Mount Rainier” graphic with students
and locate the more than a dozen lava ow ridges at Mount Rainier such as Rampart,
Paradise, and Mazama Ridge. Optionally, instruct students to nd these ridges on a
topographic map of Mount Rainier. What type of features are located adjacent to
ridges? (answer is glacial valleys). These ridges were formed during successive ice
ages 500,000–11,000 years ago.
3. Further examine the graphic “Volcanic Rocks of Modern Mount Rainier.” Look at
the general “spoked-wheel” pattern of the lava ows. Ask students if they observed a
similar process in the “Fire and Ice” simulation. Ask students why there are gaps in
the spokes of some of the wheels. Refer back to the “Fire and Ice” volcano model
for clues. Ask students how weathering and erosion could have changed the ridges
over the course of the last 10,000 years.
4. Make the process relevant to the situation today. In the absence of glaciers that
envelop the entire volcano, and recent lava ows, are the current valleys at Mount
Rainier being built or carved by glaciers? Glaciers are eroding the valleys. Students
should also recognize that today’s glaciers are small and constrained within valley
walls, and are incapable of routing the course of lava ows as in the days of the ice
ages.
Adaptations
◆
Use modeling clay on a relief map to simulate large glaciers from the ice age. Lift
the modeling clay and examine the shapes on the underside. Students note that the
clay glaciers are thicker in valleys between the ridges.
◆
Take time-lapse photographs of your experiment.
12
13
Fire and Ice
-
continued . . .
Extensions
◆
Instruct students to conduct research projects about glacier-volcano interactions.
Students can visit Web sites listed on the Internet Resources List to identify landscape
features that are products of glacier-volcano interactions at Cascade volcanoes,
Iceland, and elsewhere.
◆
Engage the class in a discussion of energy transformations using these
concepts: As the blocks of lava begin to avalanche down the mountainside, the
lava begins to accelerate. If you’ve ever tried to carry a large block up a
mountain, you know that it takes a lot of energy! Once you drop that block
down the mountain side and it begins to roll, the energy that it took to lift it up
the mountain is converted into kinetic energy—the energy of motion.
◆
Engage the class in a discussion of heat transfer between lava and glacier ice
along the following concepts: Many lava ows that issue from steep-sided
volcanoes break up into blocks and rubble that avalanche down the slope and
mix with snow and ice. The melting of snow and ice by this process has the
potential to create lahars that travel great distances beyond the slope of the
mountain and threaten nearby communities.
A s se s s m e n t
Use the questions in the “Fire and Ice Simulation” to assess students’ thinking as it
progresses through recognition that glaciers inuence the landscape on a volcano. Note
how students’ understanding develops from general observations of the volcano model
to recognition of the processes that shape an actual ice-covered volcano. As the activity
progresses, students should recognize that the volcano and glaciers co-exist as a dynamic
system and that many geologic and hydrologic features on the volcano are the results of
glacier-volcano interactions. Students should begin to think more globally, and recognize
that glaciers can inuence the shape of glacier-clad volcanoes worldwide. To further assess
their understanding, instruct students to write a summary paragraph about glacier-volcano
interactions.
References
Crandell, D.R., and Miller, R.D., 1974, Quaternary stratigraphy and extent of glaciation in
the Mount Rainier region, Washington: U.S. Geological Survey Professional Paper
847, 59 p.
Driedger, C.L., 1986, A visitors guide to Mount Rainier glaciers: Pacic Northwest
National Parks and Forests Association, 80 p.
Driedger, C.L., and Kennard, P.M., 1986, Ice volumes on the Cascade volcanoes:
Mount Rainier, Mount Hood, Three Sisters, and Mount Shasta: U.S. Geological
Survey Professional Paper 1365, 28 p.
Driedger, C.L., 1993, Glaciers on Mount Rainier, U.S. Geological Survey Fact Sheet,
Open-File Report 92–474, 2 p.
Lescinsky, D.T., and Sisson, T.W., 1998, Ridge-forming, ice-bounded lava ows at Mount
Rainier, Washington: Geology, v. 26, pp. 351–354.
Lescinsky, D.T., and Fink, J.H., 2000, Lava and ice interaction at stratovolcanoes: use of
characteristic features to determine past glacial extents and future volcanic hazards:
Journal of Geophysical Research, v.105, 23, pp. 711–23,726.
14
Fire and Ice
-
continued . . .
Refer to
Internet Resources Page
for a list of resources available as a supplement
to this activity.
Photo Credits
1. Glaciers on Mount Rainier, Photo by Carolyn Driedger, USGS.
2. Columbia Crest summit, Photo by Donal Mullineaux, USGS.
3. Glacier-volcano interactions, Photo by Carolyn Driedger, USGS.
4. Glacier scratches (striations) on lava rock at Mount Rainier,
Photo by Carolyn Driedger, USGS.
5. Lava Flows—Experimental and real world comparisons,
Photo by Carolyn Driedger, USGS.
Living with a Volcano in Your Backyard–An Educator's Guide: U. S. Geological Survey GIP 19
15
Glaciers on Mount Rainier
Photo by Carolyn Driedger, USGS
Living with a Volcano in Your Backyard–An Educator's Guide: U. S. Geological Survey GIP 19
16
Columbia Crest Summit
The history of glaciers and volcanic processes
has been intertwined since the construction
of the present mountain began about 500,000
years ago.
Photo by Donal Mullineaux, USGS
Living with a Volcano in Your Backyard–An Educator's Guide: U. S. Geological Survey GIP 19
Glacier Volcano Interactions
Volcano Provides:
◆
Extensive high-altitude slopes
◆
Rugged topography
Glacier Provides:
◆
Control over the behavior of lava ows
◆
Water for formation of lahars and debris ows
◆
Mechanical erosion of volcano
17
Photo by Carolyn Driedger, USGS
Living with a Volcano in Your Backyard–An Educator's Guide: U. S. Geological Survey GIP 19
Maximum Extent of Glaciers on
Mount Rainier During the Ice Ages
18
10 MILES
5
10 KILOMETERS
0
0
5
Modified from Crandall and Miller, 1974.
Living with a Volcano in Your Backyard–An Educator's Guide: U. S. Geological Survey GIP 19
How Lava Ridges are Made
19
Ice Age glaciation on Mount Rainier
―
Ice-age glaciers buried much of Mount Rainier.
Some rock ridges remained exposed.
Eruption of lava during ice ages
―
Some lava ows disintegrated as pyroclastic ows.
Others melted holes in the glacier, but later were
buried by owing ice.
This lava ow met little resistence on the rock ridge,
and owed a great distance. It cooled and hardened.
Lava ridges and glaciers today
―
Glaciers melted at the end of the ice
age. Stack of lava ows remain as ridges.
Living with a Volcano in Your Backyard–An Educator's Guide: U. S. Geological Survey GIP 19
Glacier Scratches (Striations) on Lava Rock At Mount Rainier
20
Photo by Carolyn Driedger, USGS
Living with a Volcano in Your Backyard–An Educator's Guide: U. S. Geological Survey GIP 19
Volcanic Rocks of Modern Mount Rainier
21
From Lescinsky and Sisson, 1998
Mt. Rainier
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Living with a Volcano in Your Backyard–An Educator's Guide: U. S. Geological Survey GIP 19
Lava Flows—
Experimental and Real World Comparisons
22
Lahar deposits
―
Snow and ice meltwater
from pyroclastic ows formed this lahar deposit,
which is represented by the ow of melted ice
cream in the experiment.
Thin lava ows on the
cone
—Thin lava ows eroded
by glaciers are represented
by thin wax lava ows that
hardened on the volcano model.
Lava ow
ridges
—A thick
stack of lava ows
built the ridges on
both sides of Nisqually
Glacier. Similar far-
traveled wax lava
ows poured down
the volcano model to
the tray bottom.
