Scott Shoup Introduction to Glacier Morphology McCallie School ...

Scott Shoup Introduction to Glacier Morphology
McCallie School
Chattanooga, TN Geology, Geomorphology
2004 MS / HS
Icelandic Glaciers 50 min class / 30 min quiz
Goal: To acquaint students with the basic structures associated with glaciers and the
forces behind the formation of these structures. It is important to convey that glaciers are
dynamic, semi fluid masses that respond to climatic change and fundamental physics.
Background Information: Students should already have discussed why glaciers form.
That glaciers build up when more snow falls in an area than melts away. Essentially the
accumulation of snow exceeds the amount of snow that melts or evaporates away. The
second important point that needs to be understood previously is that glaciers move
because of gravity and can essentially flow like a liquid.
Hazards: Food allergies particularly peanut allergies
Materials: Photographs that can be projected onto a screen of the structures listed in the
instructional procedure. I was able to take digital photographs on my trip and combine
them with other photos digitally copied. One Snickers bar per student. Paper towels.
Technology: Only what you need to project your photographs. Computer and projector.
Instructional Procedure:
1. Normal class start up procedure
2. Ask the class to write down a definition for a glacier and have a few students read
aloud their definitions.
3. Discuss the definitions presented by the students while reinforcing the background
information mentioned above. Have any of the students seen a glacier before? What
about snow?
4. Tell students to prepare to take notes and cue up slide 1. Discuss the slides but lead
students thoughts by asking leading questions.
5. Slide 1 - General view of a glacier. Reinforce the introductory material and
emphasize how gravity pulls the ice down the glacial valley. Where is the zone of
accumulation and what conditions exist there?

6. Slide 2 – View of compression zone and expansion zones that occur as the ice flows
over bumps (expansion) or into depressions (compression). Point out how the ice spreads
and breaks apart creating crevasses and how these crevasses can actually be closed back
up.
7. Slide 3 – Close view of crevasse. State something to express the scale of the
photograph and mention how crevasses can become covered by snow bridges. This is
why mountaineers stay roped together when traveling on glaciers. They could potentially
fall into a crevasse hidden by a snow bridge. What would happen to a person that fell
into a crevasse if they stayed there for 100 years?
8. Slide 4 – Drains and melt water streams. Melt water streams carry water across the
surface of the glaciers until they reach drains or moulons that allow the water to fall
vertically down into the ice. Where does the water go and does it do anything to the
glacier?
9. Slide 5 – General surface view of a glacier. How hard would it be to travel across this
glacier and what would the dangers be? Also have students create a brief description of
how they might measure movement of the glacier.
10. Slide 6 – Toe or nose of a glacier. If this was an advancing glacier what could you
say about the amount of snow and ice that is lost from this area? If this is a receding
glacier what conditions would exist? Point out how the glacier bulldozes material in
front of it and how dirty the ice becomes. Point out moraines.
11. Slide 7 – Various moraines left by a receding glacier. What can these moraines tell
us about the history of the glacier if we know the dates they where put in place? Could
these moraines ever be over run and essentially erased? Could drumlins be formed?
12. Slide 8 – Kettle Lake. These form when ice gets buried or left behind by a glacier.
This buried ice then melts and the dirt on top of the ice falls into the empty hole. This
leaves a depression full of water.
13. Turn on the lights! Hand out snickers bars to the students. Be careful about any
students that may have a peanut allergy. Milky Way candy bars can be used as a
substitute. Have them unwrap them completely but don’t eat them!
14. Have students place the candy bar on top of a clean paper towel on top of a clean
surface. Have students press down firmly on the candy bar using their entire hand in a
flat manner. Ideally the candy bar only deforms slightly because the force is distributed
over a large area. You are on a flat surface.
15. Now have the students press in the same manner as they slide the candy bar off the
edge of their surface. This simulates ice traveling off a cliff or over a bump. An

expansion zone is created causing breaks in the upper surface of the candy bar.
Crevasses!
16. Have students flatten their candy bar again by pressing gently on the flat surface.
Notice that the crevasses can be closed and reopened.
17. Now compress the candy bar from either end and you can create pressure ridges.
18. Take a big bite out of the candy bar and look at the cross section. For homework
answer the following questions.
A. If a peanut near the surface of the candy bar was removed causing a surfcae hole to
form what glacial feature might be represented?
B. If chocolate represented dirt, and caramel ice, describe how the dirt may have come to
rest on the surface of the glacier.
C. Study your notes on glaciers for a quiz.
Assessment: On the second day spend 30 mins. showing photographs of various features
you feel are important. For each photo ask students to identify a glacial feature and how
it might have formed.
Suggested Quiz Questions:
1. Wide photo of glacier. What is the definition of a glacier and what must glaciers do?
2. Photo of moraines. What is the name of this feature and why do they form?
3. Photo of crevasses. What are these breaks in the ice called and how are they formed?
4. Same photo. What gives a glacier its tremendous power?
5. Show a picture of a kettle lake. What is this feature and how is it created?
Rubrics for quiz questions:
Allow 10-point bonuses for comments or ideas that show quality thought even if they are
incorrect. This is to encourage thinking instead of memorization.
1. (20pts) A glacier is a large mass of moving ice and snow. They must move.
2. (20pts) Moraines. Advancing Glaciers push dirt and rock up into hills as they travel
forward.

3. (20pts) Crevasses. They form when ice travels over a bump and the upper surface of
the ice is stretched and broken.
4. (20pts) Gravity and lots of mass.
5. (20pts) Kettle Lake. Buried ice melts creating a cavity or hole that the surface material
falls into. What is left is a hole full of water or a Kettle lake.
Sources used for lesson plan:
Photographs taken while on Icelandic Glaciers Expedition (should be
available online). Any good geology text with information about glaciers is
useful.
Contact Information: sshoup@mccallie.org