ANSWER KEY
Name ________________________________________ Date ___________ Period _______
Study Guide:
Earth System and Layers, Constructive vs. Destructive Forces,
Plate Tectonics, & Volcanoes
Essay Questions:
1.
What was Wegener’s theory of continental drift?
Wegener’s theory was that continents originated as the supercontinent, Pangaea, then they moved
horizontally to their present location.
2.
What is the theory of plate tectonics?
The theory states that the Earth’s crust is broken into sections called plates. Convection currents
in the mantle is what causes the plates to move around.
3.
Name and describe the three types of plate boundaries.
a. Divergent- two plates move away from one another
b. Convergent- two plates move toward one another
c.Transform-fault – two plates slide past one another
4.
Describe how convection currents might be the cause of plate tectonics.
5.
The cycle of heating, rising, cooling, and sinking of the hot plastic-like rock in the mantle causes
the plates on top to move around.
What causes new material to form at a mid-ocean ridge on the ocean floor?
Hot magma is forced upward at the mid-ocean ridges. Then it turns and flows sideways, carrying
the seafloor away from the ridges in both directions.
6.
Name the two spheres that are interacting in the following situation, and explain how the two
spheres are interacting. A volcano erupting.
The rock and lava in the geosphere is erupting into the atmosphere.
7.
Label the layers that make up the Earth? Write a sentence about each layer.
1. Crust – solid, rocky outer layer (continental and oceanic crust)
2. Mantle – hot rock, where convection currents occur
3. Outer Core – molten/liquid metal made up of iron and nickel
4. Inner Core – dense ball of solid metal made up of iron and nickel
8.
Are the forces that cause lava to erupt from a volcano and flow over Earth’s surface
constructive or destructive?
The forces can be both constructive and destructive. When the lava flows over the Earth’s
surface it kills and destroys things like plants and animals. This is destructive. When the
lava hardens and turns into rock adding to the Earth’s surface, this is constructive.
9.
Describe what happens when….
a.) Two plates carrying continental crust collide forming mountains
b.) A plate carrying oceanic crust collides with a plate carrying continental crust
subduction occurs; the oceanic plate goes under the continental plate
c.) Two plates carrying oceanic crust collide and form trenches and volcanoes
10.
Answer the following questions using the diagram below.
a.) Name the feature shown at A.
Mid-Ocean Ridge
b.) What is occurring at B?
Sea-floor spreading
c.) What process is shown occurring at C, and why does it occur? Subduction, because the
ocean floor is so much heavier (denser) than the land
11.
What accounts for the differences in density between oceanic and continental crust?
Oceanic crust is made mostly of basalt, a dense rock. Continental crust is made mostly of granite,
which is less dense.
12.
Draw what scientists believed the Earth and it’s continents looked like 225 million years ago in circle
A, and then draw where the continents are located today in circle B.
A
13.
B
Explain what force caused the movement of the continents from one supercontinent to their present
position.
14.
The convection currents in the mantle caused the crust on top to break apart and drift in different
directions.
Explain the theory of sea-floor spreading and draw and label a model to explain what is occurring.
Sea-floor spreading adds more crust to the ocean floor. At the same time, older strips of rock
move outward from either side of the ridge.
15.
What is the difference between magma and lava?
Magma is melted rock found below Earth’s surface and lava is melted rock found at the Earth’s surface.
16.
What is the Ring of Fire and where is it located?
The Ring of Fire is one major belt of volcanoes that rim the Pacific Ocean.
17.
Contrast the silica content of magma in quiet and explosive eruptions.
The magma in a quiet eruption is low in silica. The magma of an explosive eruption is high in silica.
18.
Textbook pg. 178
Transform boundary
Volcanoes
Deep ocean-trench
Convergent boundary
Mid-ocean Ridge
Sea-floor spreading
Convergent boundary
Divergent boundary
mountains
Rift valley
Oceanic crust
convection
Continental crust
subduction
19.
Name and explain the three different types of heat transfer and give an example of each.
Radiation – transfer of heat through rays or waves
Ex: sunburn
Conduction – transfer of heat through touch
Ex: using a heating pad
Convection – flow of material
Ex: boiling water
20.
Where does heat come from that drives the convection currents in the
mantle? The core
Where is the temperature of the mantle greater? Closer to the core
How do you think the convection currents affected the crust material
above it? It caused the crust to break apart and move around