Classroom Activity: BUILD YOUR OWN GLACIER!
Sophie Gilbert, Ph.D. student at University of Alaska Fairbanks
Overview:
Students construct their own glaciers out of flubber, a material that exhibits viscous
flow but much faster than a glacier. Students make predictions about how slope and
conditions at the bed (lubrication) will affect glacier flow rates. Each group of
students picks one variable to work with, and designs a simple experiment to test
their hypothesis, recording the results (velocities) in a data table and comparing
final results with other groups.
Learning objectives:
Students will:
1. Understand that glaciers can move via both viscous flow and by basal sliding
at the bed of the glacier.
2. Understand that a warming climate creates more water inputs at the glacier
base, resulting in faster sliding rates.
3. Understand that bed conditions, thickness/mass, and slope of the base affect
sliding rate.
Materials:
1. Video: and introduction to glaciers with researcher Timothy Bartholomaus,
at the University of Alaska Fairbanks, downloaded at
www.gilbertresearch.org/outreach/podcast/
2. Materials to make flubber, one set of materials per group of 3-5 students:
 Glacier bases: pvc piping or carboard tube (large-ish, like a mailing
tube), cut in half to form 2 open, half-circular troughs
 Borax
 Elmer’s glue
 Food coloring, colors of your choice
 Warm water
 Toothpicks
 Sharpie markers
 Paper towels for cleanup
 Scissors
 Sandpaper
 Vegetable oil


Plastic Ziploc bags to take flubber home in
Newspaper/butcher paper to cover tables with before making flubber
Procedure:
1. Watch the glaciers video as an introduction to the topic. Have the students
discuss how changing the glacier’s slope, thickness (mass), and lubrication of
the bed of the glacier might affect it’s speed (velocity). How might a warming
climate change the thickness and lubrication at the base through melt?
2. Make flubber, using the recipe below, in two separate big batches (one white,
one a color of your choice)
Flubber recipe, for one batch:
Mixture 1:
¾ cup warm water
1 cup elmers glue
*food coloring, for the colored recipe
Mixture 2:
2 tsp. borax
½ cup warm water.
Stir mixture 1 together in 1 bowl, mixture 2 in another bowl.
Make sure both are mixed well. Pour mixture 1 into mixture 2,
mix gently with your hands (this is the fun part!). Now you
have flubber. Can be made ahead of time and stored, wrapped
in plastic, for several days.
3. The teacher sets up a demonstration flubber glacier for the students to model
theirs on, looking something like this one below. Allow the glacier to “flow”
so the students can get a feel for how flubber behaves.
4. Students form groups of 3-5, and generate hypotheses about how a) changing
the slope of the glacier will change its speed, b) changing the lubrication at
the base of the glacier will change its speed, and c) changing the thickness of
the glacier will change its speed.
Hypothesis: write down your hypothesis about what you think will happen if:
Hypothesis 1: we think the flubber glacier will move_____________
blank with FASTER or SLOWER) if the slope becomes steeper.
(fill in the
Hypothesis 2: we think the flubber glacier will move _____________
blank with FASTER or SLOWER) if the bed is more lubricated.
(fill in the
Hypothesis 3: we think the flubber glacier will move_____________
blank with FASTER or SLOWER) if the glacier is initially thicker.
(fill in the
5. Each student group designs an experiment to test what influences glacier speed,
based on the hypotheses you generated. You can test different slopes for the ice
(flubber), different base lubrications, and different thicknesses.
6. Set up the experiments. To determine the velocity, make sure you measure (with
a ruler) how far the flubber moves in a given amount of time. Record your results
below. Remember, velocity is found by dividing distance travelled by time taken
to travel that distance (Vecolity= Distance/Time).
Velocity Tables:
Thickness test: make two thicknesses of glacier, and record the thicknesses below. Keep
the slopes and base lubrications the same. Record how far and how fast the glaciers travel
below.
Mass- thick (__cm deep) Dist:
Time:
Velocity:
Mass-thin (__cm)
Dist:
Time:
Velocity:
Basal conditions/lubrication test: make two glaciers, one with lubrication at the base
(rub vegetable oil on the base before adding flubber layers) and one without lubrication.
Record how far and fast the glaciers travel.
Sandpaper Base
Dist:
Time:
Velocity:
Normal Base
Dist:
Time:
Velocity:
Veg Oiled Base
Dist:
Time:
Velocity:
Slope test: make two glaciers, one tilted at a steep angle and one more shallowly. Record
how far and fast the glaciers travel.
Slope - shallow
Dist:
Time:
Velocity:
Slope - steep
Dist:
Time:
Velocity:
7. Glacier races! Based on your new knowledge about glaciers from your
experiments, each group designs the ultimate speedy glacier based on slope,
lubrication of the base, and thickness of the glacier. Then, have a glacier race
between groups to see whose reaches the bottom of the trough/bed first.
8. Conclusions: write a paragraph about what factors can change the speed of a
glaciers’ movement.
Extension Ideas:
1. Take a piece of flubber and pull until it breaks. What evidence of this “pull
until it breaks,” property can we see in real glaciers (think crevasse patterns,
ice falls)?
2. Put toothpicks in a line along the glacier, and watch how they move relative
to one another over time, and how they bend forward. How can we explain
this pattern based on viscous flow and friction along the sides and bed of the
glacier? What evidence of this can we see in real glaciers (think moraines)?
3. For at least one of your experiments, push toothpicks (vertically) into the surface
of the flubber. Draw how they move / change direction during the experiment.
What do you think this means about how fast the flubber is flowing at the surface
vs. the bed of the glacier, and in the center vs. at the edges of the glacier\/
Flubber drawing: