AliButt_Lab5
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Georgia State University *
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1122
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Geology
Date
Apr 3, 2024
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docx
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Uploaded by GrandEel3903
Name: Ali Butt
TA: Carley Wilshire
Lab 5- Glaciers
GEOL 1122
Before answering the questions for each section, make sure you have watched the video(s). After
you have completed this worksheet, save it and upload it to the assignment folder for Lab 5 in iCollege.
Lab Objectives
At the end of this labs, students should be able to:
Understand how glaciers form and the anatomy of a glacier
Describe how and why glaciers move
Compare a kitchen model of glaciers to the actual movement of glaciers
Explain the physical interactions between ice and the ground and how glaciers shape the landscape
Identify glacial landscape features in areas that no longer contain glaciers
Part 1: Introduction
To answer these questions, first watch the “Lab 5, Part 1: Introduction” video on iCollege
1)
Hypothesize: what matters more in determine if glaciers exist: summer or winter temperatures? Why? (4 pts)
Because summer temperatures directly affect ice melting, which can cause glaciers to retreat, summer temperatures have a greater impact on the existence of glaciers. While summer warmth has a greater effect on the overall balance of glacier mass, winter temperatures do play a role in accumulation.
2)
How is a glacier different from a snowy field? (4 pts)
An area of accumulated snow that is level and lacks the pressure or movement required to generate glacial ice is called a snowy field.
A glacier is a mass of ice that moves due to gravity and its own weight.
While snowy fields do not have the features of glacial movement and usually stay immobile, glaciers experience compaction and flow.
3)
Why are most glaciers on Earth located at high latitudes (near the poles)? (2 pts)
Because it is colder and there is more snow there almost all year round, high latitudes are home to the majority of the world's glaciers. Under those circumstances, glaciers are more likely to persist.
4)
In the context of climate change, describe what is happening to the zone of accumulation and the zone of ablation in glaciers today? (6 pts)
The summit of glaciers is usually found high in the mountains. Glaciers grow as more ice
and snow are added to them because it is possible for there to be cold and snow throughout the year. This is the accumulating zone. The zone of ablation, which is the warm, lower altitude base of the glacier where large ice chunks break off from the glacier
as it melts, is known as such. The zone of accumulation is expanding while the zone of ablation is melting faster. In the context of climate change, the glacier's ablation zone is expanding due to faster ice melt brought on by rising temperatures, which causes the glaciers to retreat overall, while the accumulation zone of the glacier is shrinking due to less snowfall and early melting.
5)
If the zone of accumulation expands, what happens to the line of equilibrium? What happens to the size of the glacier? (4 pts)
The line of equilibrium will move downward if the zone of accumulation widens. The glacier will get larger as a result of this.
Part 2: Glacial Flow
Watch the linked YouTube video “How Do Glaciers Move” from 2:40 to 5:22 to answer these questions
6)
Why is the bottom of the glacier under the most pressure? (2 pts)
Because of the pressure melting point, the glacier's base is under the greatest amount of pressure.
7)
What is the difference between the zone of plastic flow and the zone of brittle flow? (4 pts)
The glacier's top layer is known as the zone of brittle flow and it is not under much pressure but when you apply stress it’s prone to cracks, while the lowest/deepest layer is known as the zone of plastic flow.
8)
Why do crevasses form? (2 pts)
Stress from pressure on the ice causes crevasses to form which are actually cracks.
9)
Why do glaciers move? (4 pts)
Some glacier movement comes from slipping of sediments or a thin layer of water. The deforming process and climate both also contribute to the movement of glaciers.
Part 3: Kitchen Glacier
Watch the “Lab 5: Part 3: Kitchen Glacier” video on iCollege to answer these questions. Instructions are given in the video if you want to build your own glacier!
10) What do you observe about the ooblek? (2 pts)
Ooblek is a blend of cornstarch and water; to put it another way, it's like a potpourri of solid and liquid.
11) Looking at the experimental setup, write three hypotheses of what you think might happen. Explain WHY you think each might happen. (6 pts)
Observing the experimental configuration, I believe the ooblek will not descend, or that the foil may prevent it from doing so. I also speculate that it may move due to the way it forms.
12) After the experiment, evaluate if each of your hypotheses were correct or not. If they were wrong, brainstorm why. (6 pts)
First two hypotheses are wrong as it moved. Last hypothesis was correct because of the shape it formed.
13) Use the final time and distance to calculate the velocity of the kitchen glacier in cm/second. How does that compare to the velocity of Mendenhall Glacier from the previous video? Make sure to show your work! (6 pts) Hint: you will need to convert units, so here’s some help:
To go from seconds to days, multiply by 86,400
To go from inches to meters, divide by 39.4
20 sec * 86400=1728000 sec
16 inches / 39.4= 0.4060 m
0.4060 / 1728000 = 0.00000023 m/sec
Part 4: Glacial Landforms
Watch the “Glacial Landforms” video to answer these questions. 14) Describe how glaciers cause erosion. (4 pts)
Plucking, or the act of picking up boulders as water flows and turning them into ice, is one-way glaciers contribute to erosion.
Another reason is abrasion, a second type of glacial erosion where boulders embedded in the glacier's sides and base act as sandpaper, scratching against the nearby valley floor and walls. Abrasion leaves behind tell-tale striations in the bedrock that determine the direction of motion of ancient glaciers.
15) What is the difference between a V-shaped valley and a U-shaped valley? (4 pts)
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A valley with a V-shaped appearance is caused by erosion from powerful stream. Whereas, the plucking and abrasion of glaciers causes a U-shaped valley to resemble a U,
with flat valley bottom and steep sides e.g., Beartooth Mountains in Montana.
16) Would you expect to see glacial landforms in Atlanta? Why or why not? (6 pts)
No, as Atlanta is situated in an area that has never seen glaciers, glacial formations would
not be expected there. During ice ages, which did not reach as far south as Atlanta, glaciers covered areas that are now home to formations like eskers, drumlins, and moraines. This notion is further supported by the lack of glacial erosion and deposition processes in the area. Also, the fact that Atlanta is warm enough to not have enough support for a glacier to exist or form.
When you have finished answering all of these questions, make sure you save this file with your last name at the beginning of the file name and upload it to the correct iCollege Assignment folder!