Antarctica’s Climate Secrets – Poster 2
Antarctica’s Ice on the Move
Antarctica’s Climate Secrets – Poster 2
Antarctica’s Ice on the Move
Slow moving water
There’s no doubt about it — Antarctica is an icy place. About 70% of Earth’s
fresh water is trapped as solid ice on this large southern continent. The
ice there has been accumulating for over 35 million years, piling up one
snowstorm at a time. Just as liquid water flows downhill, solid water does too,
but on a much longer time scale. Its shape can change though the ice remains
solid.
Ice terms
Three names for one kind of ice
Ice that covers the continent of Antarctica is part of an ice sheet. Some parts of
the ice sheet are over 3 kilometers (2 miles) thick. At its base, an ice sheet moves
over land, grinding over mountains and valleys and carrying rocks downhill.
Around the edges of the continent, ice sheets flow off the land and extend out
over the ocean. The floating outer edges of the ice are called ice shelves. Ice
shelves cover large areas of ocean around Antarctica, especially in bays and
inlets along the coastline. Ice shelves are about as thick as a football field is
long, around 100 meters (300 feet).
At the outer edges of ice shelves,
tidal motions and other forces break
large pieces of ice from the shelves.
The parts that break off — called
icebergs — float on their own, no
longer attached to land.
Ice sheets, ice shelves, and icebergs
are all made of fresh water ice: they
started as snow that fell from the
sky. The three different names refer
to where the ice is.
ice sheets — enormous masses
of glacial ice and snow that cover
huge areas of land
ice shelf — portions of an ice
sheet that extend off a continent
and float on sea water
iceberg—A chunk of ice that
breaks off an ice shelf
sea ice — frozen ocean water
Ice Sheet
Ice Shelf
Sea Ice
Icebergs
NASA Scientific Visualization Studio, modified by Angie Fox
One More Kind of Ice
Sea ice is another kind of ice: it forms when the surface of the ocean gets so
cold that it freezes. It’s similar to ice that forms on the surfaces of ponds and
lakes. As sea ice is frozen ocean water, it is salty rather than fresh. Compared
to ice shelves and icebergs, sea ice is thin. First-year sea ice is around a meter
thick; multi-year sea ice can be up to around 10 meters (33 feet) thick.
Page 1
Antarctica’s Climate Secrets – Poster 2
A Glacier is Formed
Imagine what would happen if more snow fell every winter than could melt
away in the summer. During the first storm of each winter, fresh new snow
would land on top of the previous year’s dusty old snow. More new snow would
be added to the top of the pile with each storm. During summers, the surface
would again get dusty. After a
century or more of making these
layers, the pile of snow would
grow quite thick. The darker
summer surfaces would form
layers that mark the top of each
year’s snow. The weight above
them would eventually compress
layers of snow near the bottom
of the pile. Individual snowflakes
would be squeezed together so
tightly that they would merge
together into solid ice. When the
snow-turned-to-ice began to
flow downhill under the force of
Glacier-filled valleys in Antarctica. Photo by Michael Rynbrandt, National Science Foundation
gravity, a glacier has formed.
At the bottom of the glacier
Even when a pile of snow gets larger every year, some snow melts during the
warmer months. Liquid water trickles down to the land below the snow. When
this water refreezes, it expands, and rocks from the surface get frozen into
the bottom of the glacier. As the glacier moves downhill, it carries these rocks
with it, and the rocks and ice grind over the land.
Poster Discussion Guide
Divide your class into groups of 3-4. Hand out copies of the Question Starters
sheet on Page 3 (a modified version of Bloom’s Taxonomy) and have each group
develop at least five good questions that can be answered with the information
found on the poster. Challenge the groups to come up with at least one question
in each of the five categories. You might need to practice a few of the different
types of questions using a topic they know well (e.g., sports, hobbies, pets). Point
out the hierarchical structure of the list from basic recall questions to the higher
level questions involving analysis and evaluation. Students may need additional
information and encouragement to come up with Evaluation-level questions.
Bloom’s Taxonomy
Have groups trade their completed charts with another group and answer the
questions they received. Assess student understanding by considering groups’
answers as well as their questions.
A good resource of information
about ice is the National Snow and
Ice Data Center at http://nsidc.org/.
Page 2
In the 1950s, Benjamin Bloom
developed a classification
system for learning that begins
with simple recall of facts and
progresses through higher-order
thinking skills.
Ice info
Antarctica’s Climate Secrets – Poster 2
Group Members ______________ ______________ Date _ _______________
______________ ______________
Question Starters for “Ice on the Move”
Category
Knowledge
• what, when, where
• list
• define
• name
Comprehension
• explain
• identify
• locate
Examples
What is _ _____________________________________?
Define ________________________________________
List the five kinds of ice found in Antarctica _______________
Can you locate _ ________________________________?
Explain how ___________________________________ .
Identify ______________________________________ .
Analysis
Compare __________________ to _________________ .
• compare
• contrast
How are they similar?
How does _______________differ from ______________?
Evaluation
• judge
• assess
• evaluate
• predict
• conclude
• “what if?”
What is your opinion of ____________________________?
What is the best solution to _ ________________________?
Predict _ _____________________________________ .
What would happen if _____________________________?
What do you think will happen _______________________?
What do you conclude about _ _______________________?
Page 3
Antarctica’s Climate Secrets – Poster 2
Activity: When Ice Meets the Sea
Time
0°
Tools & Materials
Weddell
Sea
LARSEN
ICE SHELF
FILCHNER
ICE SHELF
EAST
RONNE
ICE SHELF
WEST
ANTARCTICA
AMERY
ICE SHELF
90°E
AN
TA
R
ANTARCTICA
CT
°S
80
AI N
UN T S
Ross
Sea
MO
ROSS
ICE SHELF
IC
Over time, ice flows
downhill. Parts of an ice sheet
flow off the continent and float
on ocean water. Floating ice
that is still connected to land is
called an ice shelf.
1 hour
TR A N S
On Antarctica, glaciers have
grown so large that they
have merged together
to cover large areas
of land. These thick
masses of glacial
ice on East and
90°W
West Antarctica are
called ice sheets.
In the northern
hemisphere, an ice
sheet also covers
Greenland.
°S
0
60
1000
Kilometers
180°
Ice sheets cover both East and West Antarctica.
The Ross Ice Shelf is Antarctica’s largest ice shelf;
it is about the same size as France. The RonneFilchner Ice Shelf is the second largest.
At the leading edge of ice shelves, sections of the ice occasionally break off:
free-floating chunks of this glacial ice are called icebergs.
Frozen seawater on the ocean surface is called sea ice. Each winter, the area
covered by sea ice around Antarctica expands. By summer, much of it melts
away again, leaving open ocean in its place.
In this activity, students make a model to show all five of these environments,
and check out what happens on the seafloor when ice meets the sea.
Make a model ice sheet
1. Add water to the baking pan until it is about ½ inch (1 cm) deep.
2. Sprinkle two or three tablespoons (30–45 ml) of pebbles, sand, and
clay across the bottom of the pan, then place it in the freezer.
3. Leave the pan in the freezer until it is frozen solid (at least one hour).
Page 4
• Mixture of gravel, sand, & silt
(2-3 tablespoons)
• Square or rectangular baking
pan (glass or metal)
• Paint roller tray
• Paint roller tray liner
• Water pitcher
• Blue food coloring
• Salt (2 tablespoons)
• Water
• Freezer
Antarctica in Winter
Antarctica in Summer
Gray represents the area covered by
sea ice during Antarctic winter and
summer.
Antarctica’s Climate Secrets – Poster 2
1. The paint roller pan represents a section of the coastline of Antarctica.
Set the pan on a sturdy surface and put the liner in the pan. Keep a
towel nearby for wiping up spills.
Land
2. Mix up a pitcher of “seawater” by adding 2 tablespoons (30 ml) of salt
to 2 quarts (2 liters) of warm tap water. Add a few drops of blue food
coloring to help you tell the difference between the water and the ice.
Shoreline
Prepare an Antarctic Coastline
Ocean
3. Pour the blue water into the paint pan until the water level is about 1
inch (2 cm) from the top edge of the pan.
4. Cut a piece of white printer or copier paper that will fit on your ocean.
Float it on top of the blue water to represent sea ice.
Move the Ice Sheet into the Ocean
1. Get the model ice sheet out of the freezer. Dip the bottom of the pan
into warm water for 30 seconds or so to make it easier to remove the
ice sheet from the pan.
2. Set the ice, sediment side down, on the land part of the paint pan. It’s
okay if some of the ice extends beyond the pan. In this position, the ice
represents an ice sheet.
3. Model the slow downhill motion of the ice sheet by pushing the ice
down the slope about ½ inch (1 cm) every minute. Carefully apply some
gentle downward pressure on the ice as you move it forward—this
will model the grinding action of sediments in the bottom of the ice
scraping over the land.
The thickness of the model sea ice
(paper-thin) is about right compared
to the thickness of your model ice
shelf.
4. After about 10 minutes, lift one side of the ice sheet to check what’s
happening right at the leading edge of the ice.
5. As the ice sheet moves into the model ocean and becomes
an ice shelf, the sea ice (paper) will likely buckle and fold,
forming a pressure ridge, just as real sea ice does. Once
students have compared the ice shelf with the sea ice, have
them remove the sea ice to avoid a mess.
Ice Sheet
Ice Shelf
6. Stop moving the ice sheet when part of it is still on land but
much of it is floating in the model ocean.
7. After the leading edge of the ice shelf has been thinned by
melting, students may be able to break off chunks of ice to
show how icebergs form.
Pressure Ridge
Sea Ice
Dominick Dirksen, National Science Foundation
8. Once most of the “ice shelf” has melted, have students examine the
bottom of the paint tray. Ask them what the result tells them about
what happens underneath a real ice shelf? Have them share their
ideas with their team.
Page 5
Antarctica’s Climate Secrets – Poster 2
Ponder…
Compare your model to the diagram below. Based on what you saw in your model, describe the type
of sediments you would expect to find on the seafloor at letters A, B, and C on the diagram.
Ice Sheet
Iceberg
Ice Shelf
Land
(Rock & Sediments)
Sea Ice
Ocean water
Seafloor
A
B
C
How is ice on Antarctica similar to rivers on other continents?
Page 6
Open Ocean
About Antarctica’s Ice On the Move
Antarctica’s Ice On the Move is one of five banners produced for the Antarctica’s Climate
Secrets project. The project offers a complete set of hands-on activities, video podcasts, and
museum-quality banner graphics that feature scientific research in Antarctica.
The package is designed for students or youth groups to complete the learning activities,
and then use their banners, props, and models to host an informal science event. The event is
called a Flexhibit – a flexible exhibit that can work in museums, schools, and other venues. At
their Flexhibit, youth are the expert presenters, explaining what they’ve learned and doing
demonstrations to share their knowledge.
Electronic copies of Antarctica’s Climate Secrets materials can be downloaded for free. For your
convenience, hard copies of the banners and activity book can be ordered and shipped to you
at cost. Access the materials and order form at:
http://www.andrill.org/flexhibit/
For questions or further information, contact Louise Huffman, ANDRILL Coordinator of
Education and Outreach, at [email protected].
© Copyright 2008 University of Nebraska State Museum, Lincoln, Nebraska
Permission is given to reproduce these pages for educational use.