Download Conclusion: The seafloor is spreading or tectonic

Strategies for Answering W.R.
Questions
• Re-write the prompt as questions. Write one question
for each part of the prompt that requires an answer.
• Answer each question.
– Begin each answer by restating the question.
– Complete the sentence with information that you learned in
class.
• Include any additional information in another sentence.
• Read your answer.
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–
–
–
Does it make sense?
Could someone not in this class understand your explanation?
Does it answer all parts of the question?
Is it written in complete sentences?
Magnetic Stripes
225 mya
N
S
200 mya
S
N
150 mya
N
S
100 mya
S
N
50 mya
N
S
Present Day
S
N
Complete these sentences below
your drawings
The newest crust is _#________ because it
formed most recently. It is formed when
___________ and creates a __________.
The oldest crust is located _________. It is
being __________ and forming a ______.
There are patterns of _________. These
are called _______________.
How are magnetic stripes formed?
Grading Responses: Magnetic Stripes
• Is the evidence stated? (2 pt)
– Evidence: There are patterns of magnetic polarity on
the ocean floor
• Does the answer state what is proven by the
evidence (a conclusion)? (2 pt)
– Conclusion: The seafloor is spreading or tectonic
plates are moving apart
• Does the answer explain how that evidence was
used to make that conclusion? (2 pt)
– Explanation: Because the ocean floor has different
polarity, the pieces of the seafloor must have formed
at different times. This shows that the seafloor must
have been moving.
Grading Responses: Age
• Is the evidence stated? (2 pt)
– Evidence: The seafloor is oldest near ocean trenches and
newest near ocean ridges.
• Does the answer state what is proven by the evidence (a
conclusion)? (2 pt)
– Conclusion: The seafloor is spreading or tectonic plates are
moving apart
• Does the answer explain how that evidence was used to
make that conclusion? (2 pt)
– Explanation: Because the ocean floor is newest near the ridges,
that crust must have been formed most recently. This shows
that new ocean floor has been created as the tectonic plates
move apart (or as the seafloor spreads). Because the ocean
floor is oldest near the trenches, the crust must be being pushed
back into the mantle.
Grading Responses: Topography
• Is the evidence stated? (2 pt)
– Evidence: Ocean ridges and trenches are present on
the seafloor.
• Does the answer state what is proven by the
evidence (a conclusion)? (2 pt)
– Conclusion: Plate tectonic movement is creating
these features
• Does the answer explain how that evidence was
used to make that conclusion? (2 pt)
– Explanation: Ridges are formed when… Trenches
are formed when…
Focus Question: Max = 18pts
For each piece of evidence, state what the
evidence is and how it supports plate tectonics.
(1 pt per evidence, 2 pt per explanation)
• Magnetic Patterns
• Age
• Topography (ridges, trenches)
• Fossil evidence
• Appearance of continents (puzzle pieces)
• Ancient Ice sheets
Plate Boundaries
Divergent Boundaries
• Rift Valleys
• Mid-Ocean Ridges (sea-floor spreading)
• Gently-sloped Volcanoes
Convergent
Boundaries
• OceanicContinental &
Oceanic-Oceanic
– Subduction
– Trenches
– Volcanoes
• ContinentalContinental
– Mountains
Transform Boundaries
• Faults