Download Name

Name:__________________________
Science Class Period: _______
Date:_____________
Adapted from Michael Osborn Fayetteville-Manlius HS
Lab 7: Planet Earth in Cross Section
Objectives:
Devise a model of the layers of the Earth to scale.
Materials:
Calculator
Ruler
Pencil
Meter Stick
Register Tape
Colored Pencils
Background:
Planet Earth is organized into layers of varying thickness. This solid, rocky planet becomes denser as one
travels into its interior. Gravity has caused the planet to differentiate, meaning the denser material has been
pulled towards Earth’s center and less dense material mitigates to the surface. What follows is a brief
description of each layer beginning at the center of the Earth and working out towards the atmosphere.
Inner Core – The solid innermost sphere of the Earth, about 1271 kilometers in radius.
Outer Core – A layer surrounding the inner core that is about 2270 kilometers thick and has the properties
of a liquid.
Mantle – A solid, 2885 kilometers thick layer of ultra mafic rock located below the crust. This layer is the
thickest layer of the earth.
Asthenosphere – a partially melted layer of ultra mafic rock in the mantle located below the lithosphere.
Tectonic plates slide along this layer.
Lithosphere – The solid outer portion of the Earth that is capable of movement. The lithosphere is a rock
layer composed of the crust (felsic continental crust and mafic ocean crust and the portion of the mafic upper
mantle situated above the asthenosphere.
Hydrosphere – Refers to the water portion at or near the Earths surface. The hydrosphere is primarily
composed of oceans, but also includes lakes streams and ground water.
Atmosphere – the layer of gases that surround our planet. Earth’s atmosphere is composed primarily of
nitrogen and oxygen and is broken down into distinctive layers based on temperature differences.
Troposphere – a 10-12 kilometer layer of the atmosphere next to the Earths surface in which temperature
generally decreases rapidly with altitude.
Stratosphere – The layer above the troposphere in which temperature increases with an increase in
elevation. The stratosphere contains the ozone layer.
Mesosphere – The layer above the stratosphere in which temperature decreases with altitude.
Thermosphere – The outermost layer of the atmosphere located above the mesosphere. In this layer
temperature rapidly increases with altitude.
In this lab a model of the layers of the Earth will be constructed to scale using a cash register tape. The tape
will represent a “column” of the Earth from its center to the outermost portion of its atmosphere. This crosssection model will be constructed to a scale of 1 centimeter is equal to 100 kilometers.
Note at this scale one centimeter of register tape equals 100 kilometers. The average width of a line drawn
by a sharp pencil varies from 0.05 to 0.08 cm. Therefore, with the width of a pencil used to draw a layer will
range from 5 to 10 kilometers.
Method:
1. Cut a 90 cm piece of register tape. You may wish to secure each end of the paper to a table top with
a piece of tape.
2. Use a ruler and neatly draw a line perpendicular to the length of the tape roughly 10 centimeters from
one end. This will be the starting line for all the layers.
Starting point (picture not drawn to scale)
Inner core
Outer core
Mantle
3. Calculate the scale distance for the Earth (non atmosphereic layers) and note it in the table below. To
do this, divide the average thickness of the layer by 100 and round to the nearest tenth!. Below is an
example.
4. The radius of the inner core is 1276 km. Thus, 1276 / 100 = 12.7 cm thick layer drawn on the
register tape. Note the scale distance for all the layers on the data table below.
LAYER
Inner core
AVERAGE THICKNESS
1271 km
Outer core
2270 km
Mantle
2885 km
Asthenosphere
200 km
Lithosphere
100 km
SCALE IN CENTIMETERS
12.7
5. Using a pencil, mark the layers of the Earth onto the register tape based on your calculations. Begin
from the center of the Earth and add each successive layer in order. Label each layer.
(Refer to the table and diagram above for clarification).
6. Calculate the scale distances for the atmosphere using the table below. Draw the layers of the
atmosphere by marking the boundaries and “pauses”. Remember, 1 centimeter is equal to 100
kilometers.
BOUNDARY
Troposphere
AVERGE THICKNESS
12 km
Stratosphere
50 km
Mesosphere
80 km
Thermosphere
140 km
SCALE DISTANCE IN CM
7. Using page 10 of your ESRT’s, label on the model the density of the inner core, outer core and
mantle
8. Finally, color the inner core yellow, the outer core orange, the mantle red, the asthenosphere light
brown and lightly pencil shade the lithosphere. Color the troposphere light blue, the stratosphere
green, the mesosphere dark blue and the thermosphere dark green. Shade the remaining space
black.
Directions – Answer the following questions using the model, a ruler, a calculator and your Earth
Science Reference Tables.
1. How are the different layers of the solid Earth separated? (Hint: Why is the inner core on the
“bottom” and the Lithosphere in the “top”?)
2. If the actual radius of the earth is 6,378 km but a student measured it to be 6,006 km. What is the
students percent deviation (percent error)? Show all work and express answers to the nearest tenth!
Formula Used
Plug in the numbers
Answer with proper label.
Using page 10 of the ESRT’s, answer the following questions
1) The outer core begins at a depth of ______________and ends at _________________________ km
2) The density of the continental crust is _______?
The density of the stiffer mantle is _________?
3) At 3000 km, pressure = ______________________ temp = _____________________________.
4) At 5000 km, pressure = _______________________temp = _____________________________.
5) What layer of the Earths interior contains convection currents, which are believed to be the driving
force behind plate tectonics. ______________________________?
6) What is the inner core inferred to be composed of? __________________ _____________________
Using Pages 11 and 14 of the ESRT’s, answer the following questions
1) What are the two most abundant elements by mass in the earths crust? _________________________
2) Which layer of our atmosphere is the troposphere? ________________________________________
3) What is the least abundant element by volume in the crust? (“other” is not an element) ?___________
4) What is the most abundant element in the Earths troposphere? _______________________________
5) What is the third most abundant element by volume in the Earths crust? _______________________
Using Page 14 of your ESRT’s, answer the following questions.
1. What happens to pressure as altitude increases within our atmosphere? ________________________
2. What is the only layer in our atmosphere that contains water vapor? __________________________
3. As altitude increases within the Stratosphere, what is happening to air temperature? ______________
4. What is altitude of the stratopause?
_______________________ miles
_______________________kilometers