Download Lesson 2: “Seafloor Spreading”

Lesson 2: “Seafloor Spreading”
1. During World War I, scientists used underwater ________________ to detect the
varying depths of the ocean. This is known as “sonar” today.
2. While using this method of echo location, they discovered an underwater system of
____________________ (mountains) and ____________________.
3. In the Atlantic, Pacific, and other oceans around the world are a system of ridges
called “______________________” ridges.
4. In some of these ridges are long rift valleys where _____________________ and
_______________________ occur from time to time.
6. Seafloor spreading occurs when the seafloor spreads apart and hot _____________
seeps up to the crust where it _____________, _________________ and forms a
new ________________________. Underwater volcanoes are found here.
7. This colder and denser seafloor ___________ and continues to form ridges.
8. There are two things that provide evidence/proof of seafloor spreading:
a) ______________________: _________________ rock is found near the
mid-ocean ridges and the ___________ rock is farther away.
b) ______________________: The magma that is forced upward generates
______________ that supports these exotic life forms to thrive in the cold,
deep ocean.
*In the box below draw an illustration of seafloor spreading. Be sure
to label the following: rift zone, old rock, & younger rock)
Lesson 2: “Seafloor Spreading” (B)
1. During World War I, scientists used underwater (soundwaves/ cameras?) to detect
the varying depths of the ocean. This is known as “sonar” today.
2. While using this method of echo location, they discovered an underwater system of
_________________ (mountains) and ____________________.
3. In the Atlantic, Pacific, and other oceans around the world are a system of ridges
called (ocean valley/ mid-ocean?) ridges.
4. In some of these ridges are long rift valleys where _____________________ and
_______________________ occur from time to time.
6. Seafloor spreading occurs when the seafloor spreads apart and hot
(rocks /magma?) seeps up to the crust where it cools, solidifies, and forms
new (seafloor/ mountain ranges?). Underwater volcanoes are found here.
7. This colder and denser seafloor (rises/ sinks?) and continues to form ridges.
8. There are two things that provide evidence/proof of seafloor spreading:
a) THE AGE OF THE ROCKS: _________________ rock is found near the
mid-ocean ridges and the ___________ rock is farther away.
b) EXOTIC LIFE FORMS: The magma that is forced upward generates
______________ that supports these exotic life forms to thrive in the cold,
deep ocean.
*In the box below draw an illustration of seafloor spreading. Be sure
to label the following: rift zone, old rock, & younger rock)