Earth Layers
Alfred Wegener
Sea-Floor Spreading
Subduction
Challenge
100
How do geologists study Earth's interior indirectly?
a. poke it
b. drill down through all the layers
c. seismic waves
c. Looking at the speed and path of seismic waves.
100
Harry Hess provided what 3 types of evidence that supports the theory of sea-floor spreading?
(1)________ material
(2) _________ stripes
(3) _________ samples
1. molten material
2. magnetic stripes
3. drilling samples
100
Put the oceanic crust in order NEWEST to OLDEST.
Z Y X
100
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Keep studying!
100
The process of _________ adds NEW oceanic crust to the ocean floor along both sides of the mid-ocean ridge
sea-floor spreading
200
Name all the layers from the Inner core up to the crust. 
inner core, outer core, mantle, crust
200
What were three pieces of evidence Wegener used to support his hypothesis of Pangaea and the continents drifting apart over 250million years?
1. LANDFORMS (mountains and rivers fit together like puzzle pieces
2. FOSSILS (glossopteris plant, mesosaurus alligator needed fresh water, but fossils were found near salt water)
3. CLIMATE (glacier scratches, tropical plants had drifted from warm to colder climates)
200
What technology did scientists use in mid-1900's to map the mid-ocean ridge?
a. GPS
b. sonar
c. satellites
b. sonar
200
Imagine you were a piece of oceanic crust on the bottom of the ocean.
You are 200 millions of years old! It's your birthday, what process are you about to celebrate:
a. convection currents
b. subduction (sink down into the mantle)
c. erupting into new oceanic crust
b. subduction
200
1. Pressure and temperature __(increase/decrease)__ with depth.
2. The layer of Earth with the greatest (most) pressure and temperature is the __________.
1. increase
2. inner core
300
What is Earth's inner core made of?
a. milk
b. liquid metal
c. solid metal
c. solid metal
300
What were both parts of Alfred Wegener's hypothesis?
The Earth's continents had once been connected in a supercontinent called Pangaea that drifted apart.
300
In the process of sea-floor spreading, where does magma erupt on the ocean floor?
a. mid-ocean ridge
b. edges of continents
a. mid-ocean ridge
300
If subduction occurs faster at a deep-ocean trench than oceanic crust can be created at a mid-ocean ridge, the seafloor ocean will ______.
a. shrink
b. expand
shrink
300
Which diagram shows a mid-ocean ridge? Explain what happens at a mid-ocean ridge. 
C. Plates are moving apart along the boundary of 2 oceanic plates, causing molten material (magma) to rise from the mantle, erupt, cool, harden, and add solid new oceanic crust (solid basalt) to the center of the ridge.
400
What layer are convection currents flowing in the Earth?
asthenosphere
400
The theory of ______________ was that all the continents once were joined as a single supercontinent and have since drifted apart over 200 million years
continental drift
400
How did scientists discover rocks farther away from the mid-ocean ridge were older?
they determined the age of rock samples by drilling the sea floor.
400
Oceanic crust is made of a dense rock called _____.
a. basalt b. badsalt c. baasheep
basalt
400
What letter shows a deep-ocean trench? Explain what happens at a deep-ocean trench.
E. Deep-ocean trench occurs when 2 plates collide (crash). The oceanic crust is denser and plunges below the continental crust, forming a trench. The oceanic crust will subduct down back to the mantle.
500
Scientists who study the forces that make and shape planet Earth are called:
a. ecologists
b. geologists
c. biologists
b. geologists
500
To support Wegener's theory he provided evidence from __________ which are traces of ancient organisms preserved in rock.
fossils
500
What is a mid-ocean ridge?
the longest, continuous chain of volcanic mountains in the world.
500
Oceanic crust sinks into a deep ocean trench and back into the asthenosphere. This process is called _______.
a. alien abduction
b. subduction
c. subtraction
b. subduction
500
The asthenosphere is the top part of which layer of Earth?
a. lithosphere
b.outer core
c. mantle
asthenosphere is TOP of the mantle