Assignment 1_Layers of the Earth (Chandler Yen)
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Utah Valley University *
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Course
1010
Subject
Geology
Date
Apr 3, 2024
Type
docx
Pages
3
Uploaded by MinisterJellyfish19486
Name: Chandler Yen
Geology 1010
Assignment 1
Layers of the Earth
Instructions:
1)
Answer the four
questions below about the layers of the Earth. 2)
Don’t be scared of numbers,4 I will provide any equations you will need to solve the problems. 3)
Hints will be provided in green italicized
text.
4)
Take your time and have fun!
Goals:
1)
Calculate the volume of the whole Earth, mantle and core.
2)
Understand the compositions of the layers and their respected densities.
3)
Be able to draw the layers of the Earth.
Background Information:
After you have read Chapter 1 from the textbook and reviewed the lecture slides, I hope you are able to explain why Earth has layers: Earth is made of different elements that have different densities. During the early formation of the Earth, less dense elements rose toward the surface and denser elements sank
toward the center of the Earth which led to the formation of layers. In this activity, it provides you further evidence why the core has a small volume percentage relative to the whole Earth volume, but it accounts for a much bigger weight percentage of the Earth. Ultimately, I am hoping you reach the conclusion that the earth core is made of denser elements (such as iron and nickel) compared to the mantle and crust. Complete the questions below and see it yourself.
Questions:
1)
Calculate the % of the whole volume of the Earth that is occupied by the core and mantle, respectively. The formula of the volume of a sphere is 4
3
πr
3
where r is the radius of the sphere and π=3.14. The radius of the Earth is 6371 km, the radius of the core is 3471 km. The crust is so thin relative to the mantle and the core that you can ignore it in your calculations. Hints: Calculate the volume of the whole Earth first using the equation: 4
3
πr
3
. Next, calculate the volume of the core using the same equation but with the radius of the core. To get the volume of the core, divide the volume of the core by the volume of the whole Earth and multiply by 100 to convert it to get percentage of the core. Finally, subtract the percentage of the core by 100% to get the percentage of the mantle.
Volume of the whole Earth: __1083206916845.75_________
Volume of the Core: ___175167063820.964_______
Percentage of the Core: _____16%____________ Percentage of the Mantle: ___84%______
2)
Now you have calculated the % of the mantle and core
relative to the Earth by volume
, respectively. Scientists have also calculated the % of the mantle and core relative to the Earth by weight
, which are 68% and 31%, respectively. Explain why the percentages are very different in terms of volume vs. weight. Hint: think about which layer is composed of the densest elements….
I think it differs due to the density of the core. We have talked about this several times in class, but the heavier materials sank to the core before the earth cooled, therefore I think it’s easier to deduct that the core would weigh more comparatively to the mantle.
3)
Review the properties of the Earth’s interior chemical layers (Table 1). While you do not need to memorize thicknesses or densities, you should memorize composition and state. Draw a picture
, to scale, of all of Earth’s layers. In your drawing, you can ignore the thickness of the crust and use a line to represent the thickness of the crust, and then draw the mantle, inner core, and outer core. (Do NOT
post an image from the internet, etc.) Hints: There are several ways you can add a drawing. 1) You can draw the image by hand and insert it into this document. 2) You can draw the layers in Word by clicking the Insert and Shapes tabs. 3) If you are using Google Doc, you can select the Insert, Drawing, and New.
4) You can use other methods as you need.
Layers
Thickness
Composition
Density/Physical State
Oceanic Crust
3-10 km
Si, O, Fe, Mg, Al (Basalt)
2.9 g/cc SOLID
Continental Crust
30-50 km
Si, O, Al (Granite)
2.7 g/cc SOLID
Mantle
2900 km
Mg, Fe, Si, O
4.5 g/cc SOLID
Outer Core
2200 km
Fe, Ni (S, Si)
11 g/cc LIQUID
Inner Core
1300 km
Fe, Ni (S, Si)
16 g/cc SOLID
Table 1: Chemical and Density layers of the Earth
Key
Oceanic/Continental Crust
Mantle
Inner Core
4)
The layers of the Earth can also be separated by their physical characteristics (Table 2). What is the difference between the Asthenosphere, Lithosphere, Crust, and Mantle?
Layers
Thickness
Location
Physical State
Lithosphere
100-200 km
100% Crust + Upper Mantle
RIGID, SOLID, BRITTLE
Asthenosphere
100-350 km
Remaining Upper Mantle
Plastic (flows) but SOLID
Table 2: Physical layers of the Earth
Aesthenosphere is what the tectonic plates rest on, it’s really active in building the Earth’s crust. The biggest difference from the other layers is that it is a liquid (of sorts).
Lithosphere is right above the aesthenosphere and makes up a large portion of a tectonic plate. It is a solid layer of rock material. It plays a big role in the tectonic plates movement because of gravity and the
way the plate sink and rise depending on what sort of crust is formed.
Crust is a sliver of a layer that we live on. Small amounts of heavier material were trapped on the surface
of the planet when cooling. In comparison it is by far the smallest layer on the Earth, however, it is super
important because we wouldn’t have anything without it.
The mantle is a collection of the Aesthenosphere and Lithosphere and is the largest layer in the Earth.
Outer Core
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