Earth’s Interior Quiz Review Answers
Quiz Date: Thursday, November 21, 2013
As a way to prepare for the upcoming quiz, we are going to expose you to all of the diagrams that
you will be using on the assessment. By previewing these diagrams, we hope that will give you the
skills to be able to use them to get the correct answers on the quiz. Please answer the questions
that are posed about each diagram to ensure you have adequately processed how to use it!
1. Label each of the layers of the
Earth.
Up
pe
Lo
r M
we
r M
an
a
tle
n
Ou
tle
te
r Diagram A: Layers of the Earth
Crust 2. Rank the layers in order from
Co
re
coolest to hottest:
Coolest =
Crust
Inner Core Upper Mantle
Lower Mantle
Outer Core
Hottest =
Inner Core
3. Rank the layers in order from
least dense to most dense:
Least Dense = Crust
Upper Mantle
Lower Mantle
Outer Core
Most Dense = Inner Core
4. Explain why this diagram shows the mantle in two different layers.
The upper mantle is more plastic-like (can flow, like toothpaste) than the lower mantle,
which is solid.
Diagram B: Velocity of Seismic Waves
5. Mark on the
graph where
each of Earth’s
interior layers
begins. Use the
following code:
Crust = C
Upper Mantle = UM
Lower Mantle = LM
Outer Core = OC
Inner Core = IC
6. Using the graph, identify the state of matter that each of the four main layers is in:
Layer
State of Matter (solid? liquid? gas?)
Inner Core
SOLID
Outer Core
Mantle
Crust
LIQUID
SOLID (upper portion can “flow” like toothpaste)
SOLID
7. What causes the waves to change considerably at about 2900-3000 km below the surface?
Explain using the term medium (which means the material waves travel through).
The waves change the material that they are traveling though. Around 2900 km below the
surface, the waves come into contact with the liquid outer core. Because the outer core is
made of liquid, the p-waves dramatically slow down and the s-waves stop.
Diagram C: Seismic Waves
8. Which waves are faster? Explain how the graph shows this.
P-waves are faster. Their slope of their graph is more steep, which indicates a faster speed.
You can also tell by how far (distance) they travel – for example, both the p- and s-waves travel
25,000 km through Earth; it takes p-waves about 4 seconds to make the trip and it takes swaves about 10 seconds. The s-waves must be moving slower.
9. An earthquake releases both P- and s-waves at the same time. About 2 seconds after the
earthquake, p-waves are almost 10,000 kilometers away. How far have s-waves gotten?
He s-waves have gotten about 5,000 km away.
10. The further the p- and s-waves travel, what happens to the amount of time between the
arrival of the p-waves and the arrival of the s-waves?
The arrival time increases as the waves continue to travel. This means that it takes longer for
the s-waves to arrive at a location the further the waves travel.
Diagram D: Seismic Waves Travel Through Earth
11. Label the crust, mantle and outer
core on this diagram.
Crust Mantle Outer Core 12. The lines on this diagram represent
seismic waves that travel through the
interior of the Earth. Explain why the
lines do not go perfectly straight from
the focus.
As they travel through different layers,
the seismic waves change their
direction (as shown here) and speed
(as was shown on the previous graph)
because the medium through which
they are traveling changes.
13. Through which layer(s) do all
seismic waves travel?
Crust & Mantle; the waves going through
the outer core must be p-waves
14. Identify the seismic station (as indicated by the letters) shows the location where seismic
waves would be felt the most: A
15. Identify the seismic station (as indicated by the letters) shows the location where seismic
waves would be not be felt at all: C
16. Identify the seismic station (as indicated by the letters) shows the location where only pwaves would be felt (no s-waves could reach this seismic station): D
Diagram E: Earth’s Interior
17. Draw the
convection
currents (cycle
of up and down
motion) in the
correct layer of
this diagram.
18. Rank the layers
from least to most
massive (guess if
you can’t tell based
on this diagram):
Least = Crust
Inner Core
Outer Core
Most = Mantle
Material in the mantle is heated by the core; its density decreases and it rises Material towards the crust cools and becomes more dense so it sinks. Diagram F: Convection in the Mantle
19. Describe how scientists think
convection currents drive the
movement of Earth’s crust. In your
response, accurately refer to
temperature & density, including how
each concept relates to convection.
Convection currents occur in the upper
part of the mantle, where particles can
flow because they are in a “toothpastelike” or “plastic-like” substance. When these particles are lower, close to the core, they heat up
and become less dense. This causes them to rise. When they get closer to the top of the mantle,
near the crust, they become cooler and more dense, so they sink. This cycle is causing the crust
to shift, which results in earthquakes on Earth.
Essential Vocabulary
Be comfortable with all of these terms for the quiz. Ensure you know each one by completing
the chart below:
Term
Convection
Current
Definition and/or Diagram
The cycle of rising and sinking particles within the mantle due to changes in
temperature and density; cause the tectonic plates to move, resulting in
earthquakes on the surface
The inner most layer of the earth
Core
The thin outer layer of the earth
Crust
Density
How tightly packed the molecules are within an object; calculated by diving
mass by volume (mass/volume)
The point on Earth's surface directly above an earthquake's focus
Epicenter
A crack in the Earth's crust
Fault
Point inside the Earth where an earthquake begins
Focus
Inner Core
Outer Core
Primary Wave
Secondary Waves
Seismic
Surface Waves
The inner-most layer of the core (the core is actually made of two sections,
inner and outer) that is thought to be very hot, very dense & solid
The outer part of the core; based on the seismic waves, it is thought to be
liquid
Fastest seismic waves, cause rocks to compress and then spread apart
(stretching and letting go of a slinky); can travel through both solids and
liquids
Transverse waves that travel outward from an earthquake's focus and move
through Earth by causing particle in rocks to vibrate at right angles to the
direction of the wave; only can travel through solids
Relates to an earthquake
(ex: seismograph = graph of earthquake’s energy; seismologist = someone
who studies earthquakes; seismic waves = earthquake waves)
Type of seismic wave that forms when P waves and S waves reach Earth's
surface
Mantle (was left off accidentally) - The middle layer of earth, semi-liquid (or plastic-like)
Quiz Break Down:
This is a quiz, which means it cannot be retaken. However, you should know this
stuff very well! Embedded in the quiz are the “retakes” for earthquakes, density &
convection currents. If you score better on these questions when you take the quiz, I
will change your mastery check scores on these topics.
There are 31 questions on the quiz. The kinds of questions you will be asked are…
• 4 Matching questions,
• 19 Multiple Choice questions,
• 7 True/False questions; if the statement is false you will need to correct it to
make it true,
•1 Open Ended Response question.
This quiz is worth 36 points towards content mastery (which is the heaviest weighted
of all categories).