Segment Review Questions Teacher's Guide
What is a Glacier?
How does the glacier move down it’s slope? Gravity
Are all glaciers the same? No
Where are the world’s largest ice sheets found? Antarctica and Greenland
Do ice shelves float? Yes
Which are bigger, ice shelves or ice caps? Ice Shelves
From what sources might you see a valley glacier flowing? Cirques, ice caps, highland ice fields, or ice sheets
What does SAR stand for? Synthetic Aperture Radar
In what season is meltwater abundant, summer or winter? Summer
Do cold glaciers erode a lot? No
When rivers freeze, do they turn into glaciers?
Where Have Glaciers Been?
What three continents were covered in ice sheets for 2 million years? North America, Europe, and Asia
What made the glaciers melt two million years ago? Rising Temperatures
Why do geologists and glaciologists study the Ice Age? To find out what happened in the past and what may happen in the future
Do glaciers leave clues behind? Yes or No? Yes
Name two clues that glaciers leave. Scraped rock, huge boulders, u-shaped valleys, silt, fjords
What two things have to be just right for a glacier to exist? Temperature and precipitation
What does “deposition” mean? The laying down of matter by a natural process
What does “erosion” mean? Process by which material is worn away from the Earth’s surface
What is the difference between a U-shaped valley and a V-shaped valley? U-shaped valleys are formed by glaciers and V-shaped valleys are formed by rivers
Have glaciers been around where you live? How can you tell?
Anatomy and Other Diagrams of a Glacier
Is the accumulation zone near the upper or lower region of a glacier? Upper
Is the ablation zone near the upper or lower region of a glacier? Lower
The process of calving stops, balances, or increases (pick one) the flow of ice from behind? Balances
True or False: Meltwater flows along the top of glaciers. False
Explain what process is occurring in #3 on the glacier anatomy image. What does it tell you? The equilibrium line divides the accumulation zone and the ablation zone.
What is the fastest a glacier can surge? 5 times faster than it normally goes or 100 times faster than it normally goes? 100 times faster than it normally goes
In a surge, can a glacier swallow its own valley? Yes
In the diagram in this section that shows what happens when a glacier surges, look at letter B and find out what it’s about. The glacier surging, sliding downhill.
Draw a diagram of shearing at the side of a glacier. (Hint: it’s in the diagram of “types of crevasses”) Located also in the “What is a Crevasse” segment
Do you think a surging glacier could knock down Denali?
Strange Glacier Phenomena
Can glaciers make sounds? Yes. such as ice sizzles, ice quakes (a traveling/cracking sound), and the roar of moulins
What are small black wingless springtail bugs that live in firn on glaciers? Glacier fleas
What do ice worms eat? Algae and pollen
There is an image of a fossil in glacial till in this section. What is the fossil? A log or a stump
What are sudden glacial outburst floods of water that can be catastrophic? Jokulhlaups
Do ice quakes sound like earthquakes (rumbling sound) or do they make a hissing and crackling sound? Hissing and crackling sound
Are moulins holes in a glacier or the steel spikes you put on your boots to hike on a glacier? Holes in a glacier
Would you ever want to be an ice worm? Why or why not?
What are Crevasses?
What can cause a crevasse? Stress in the ice, by ice flowing over bumps or steps in the bedrock
Why don’t crevasses reach to the very bottom of the glacier? Most are squeezed shut by the pressure of the ice below about 30 meters (100 feet)
Where is the most common place on a glacier to find longitudinal or splay crevasses? Near the terminus
What causes marginal crevasses? Shear between the valley wall and the glacier
In a deep crevasse, can scientists see the ice crystals of a glacier? Yes or No? Yes
Why do scientists go down into crevasses: to observe the layers of snow or to test their bravery? To observe the layers of snow
Transverse crevasses form across a glacier where the speed is (pick one) increasing or decreasing? Increasing
Radial crevasses form where a glacier turns a corner. True or False. True
In which zone of a glacier are transverse crevasses most common? Accumulation zone
What would you do if you ever fell into a crevasse while climbing on a glacier?
Danger and Safety
What is a tower of ice surrounded on all sides by crevasses? A serac
What causes a block of ice to break off and fall? Stress
What do snow bridges cover on a glacier? Crevasses
Does wind drifting cause mechanical hardening in the snow? Yes
Should you walk over a snow bridge? No
What do glacier travelers wear on their boots so they don’t slide on the ice? Steel spikes called crampons
Name two correct ways to travel on a glacier. Travel in a team, use ropes to tie team members together for safety, have an experienced glacier climber with you, and use proper equipment.
Name a piece of proper clothing to wear when traveling on glaciers. Boots, warm jacket, warm pants, and gloves
If they go fast enough, snow machines can cross a snowbridge safely. True or False? False
What one thing you would like to do on a glacier?
How do Glaciers Form?
The formation of a huge glacier begins with a single, small _____________? Snowflake
What types of summer temperatures need to occur for a glacier to form? Cooler temperatures so snow stays on the mountain
How does over-lying weight affect the snow? It makes snow grains beneath become coarser and larger
What is wetted snow that has survived one summer without being transformed to ice? Firn
How long does it take for firn to form? About one year
When does firn become glacial ice? When the interconnecting air passages between the grains are sealed off
What is the line that separates bare ice from snow at the end of the ablation season? The firn line
What is the difference between a perennial snow patch and a glacier? A glacier flows
What causes a glacier to move downhill? Gravity
What would Alaska look like if all of the glaciers melted?
How do Glaciers Move?
What causes the glacier to be in motion? Gravity
True or False: Glaciers slide on their beds and this enables them to move faster. True
True or False: Glaciers can’t flow down to sea level or carve fjords. False
What is the zone where a glacier gains snow and ice? The accumulation zone
What is the zone where a glacier loses ice through melting and calving? The ablation zone
What is the difference between the amount of material that a glacier accumulates and the amount it loses during ablation? Mass balance
If the glacier gains more than it loses, will the glacier have a positive or negative mass balance? A positive mass balance
True or False: The snout is another name for the terminus on a glacier. True
Name one type of moraine. Terminal, lateral, or medial
When climbing a glacier, if you could only bring one other thing with you besides warm clothes, boots, and a camera, what would you bring?
Do glaciers have cows? No
What are chunks of ice that break off of glaciers and fall into the water? Icebergs
List the three rules starting with the letter “L” that you should do at Child’s Glacier. Look, Listen and Leave
Do you move to higher or lower ground when you see a glacier calving? Higher ground
One of the rules is to “Look” at Child’s Glacier. What can you probably see in the woods? Large rocks
There are photographs taken of Child’s Glacier calving. How high did the wave reach? 12 feet
What town in Alaska is Child’s Glacier close to? Cordova
If an iceberg has lots of bubbles inside, what color might it be? White
What does a darkly-striped iceberg consist of? Frozen water and moraine debris
What would it be like if you were in a boat and a glacier started to calve? Do you think it would rock your boat if you were right next to the glacier?
Why is Glacier Ice Blue?
Glacier ice is so blue because the dense ice of a glacier absorbs/reflects (circle one) every other color of the spectrum except blue/yellow (circle one). Absorbs and blue
Glacial ice is different than regular ice. True or False? True
Are there rocks in glacial ice? Why or Why not? Yes, because glaciers move through rock and soil as they carve their way down slope
What could happen to your glass of water if you dumped glacial ice in it? Your glass could explode!
What is the stuff called that is either alive now or was alive in the past (it may be trapped in glacier ice)? Organic matter
True or False? Glacial ice is just like the water in your freezer. False
What would be in your glass of water if the glacial ice melted? dirt, gravel, and organic matter (living stuff)
Glaciers are just frozen compacted snow. True or False? False
The ice on a glacier has been there for a long time and has been compacted down. True or False? True
If all the glaciers in the world melted, what would happen? (Use your imagination!)
Why do Scientists Study Glaciers?
Name one thing you can find out by studying glaciers. How the atmosphere was a long time ago
As the ice compacts, is there more/less pore space? Less pore space
Glaciers sometimes make popping sounds. Why? Pressurized air escapes from the ice
What is another big word for “warm spells”? Interglacials
How long was each interglacial period? 10,000 years
18,000 years ago, there was an ice age. How much (%) of the world’s land surface was covered under thick ice? 30%
Dr. Craig Lingle likes to study glaciers. What kind of scientist is he? A glaciologist
What is the largest glacier in North America? Bering Glacier
What did James Roush and Dr. Craig Lingle use to look at glaciers from space? SAR or Synthetic Aperture Radar satellite imagery
Do you think there will be an Ice Age or Global Warming in the next 100 years? (Don’t worry, there is no wrong answer!)