حل أوراق عمل Development of a Theory العلوم المتكاملة الصف الثامن
حل أوراق عمل Development of a Theory العلوم المتكاملة الصف الثامن
) As new seafloor moves away from an ocean ridge, the seafloor cools and becomes less dense than the material beneath it.
- True
- False
Correct Answer
False
………..The youngest rocks on the ocean floor are located
A) near continents
B) at mid-ocean ridges
C) far from mid-ocean ridges
D) near Asia
Correct Answer
B) at mid-ocean ridges
Answer Key with Questions
Lesson Check: Development of a Theory
3) Which of the following best explains the age of oceanic crust and ocean-floor features?
A) seafloor spreading
B) continental drift
C) subduction
D) crystallization
Correct Answer
A) seafloor spreading
4)________] New ocean crust is continually formed at
A) mid-ocean ridges
B) trenches
C) subduction zones
D) ocean basins
Correct Answer
A) mid-ocean ridges
5) The theory of …………….explains how new crust is created at mid-ocean ridges.
Correct Answer
seafloor spreading
Answer Key with Questions
Lesson Check: Development of a Theory
7) How does a mid-ocean ridge form?
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Correct Answer
Answers may vary.
Explanation
As the seafloor spreads apart, magma moves upward and flows from the cracks. It becomes solid as it cools and forms new seafloor. As new seafloor moves away from the ridge, it cools, contracts, and becomes denser than the material below it. This dense, colder seafloor begins to sink, helping to form the mid-ocean ridge.
Answer Key with Questions
Lesson Check: Development of a Theory
8) The map shows the ages of rocks found on the Atlantic Ocean seafloor.
a. Identify the process that causes the pattern of rock data shown in the ma
…………………………………………………………………………………
…………………………………………………………………………………
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b. Explain how the pattern provides evidence for the process you identified in part (a)
…………………………………………………………………………………
…………………………………………………………………………………
Correct Answer
Answers may vary.
Explanation
a. Plate tectonics or seafloor spreading b. New ocean crust is made at the rift zone (or mid-ocean ridge). As more crust builds up at the center of the ridge, it pushes away the older crust toward the continents. This process happens slowly over millions of years, creating a pattern of crust that gets older the farther away it is from the ridge. [Note: Student may also discuss that the pattern records changes in magnetic polarity of the oceanic crust. The different colored pattern is also used to show matching reversals in magnetic polarity of the rocks on either side of the ridge.]
Constructed-Response Rubric
: Scoring Notes
Possible answers include:
a. Plate tectonics or seafloor spreading
b. New ocean crust is made at the rift zone (or mid-ocean ridge). As more crust builds up at the center of the ridge, it pushes away the older crust toward the continents. This process happens slowly over millions of years, creating a pattern of crust that gets older the farther away it is from the ridge. [Note: Student may also discuss that the pattern records changes in magnetic polarity of the oceanic crust. The different colored pattern is also used to show matching reversals in magnetic polarity of the rocks on either side of the ridge.]
