Unit B Quiz 1 - Activities 0,1, and 2
ANSWER KEY – FORM A
Multiple Choice [Each correct answer is worth 1 point… your teacher may multiply this by another factor.]
Question
Answer
Question
Answer
Question
Answer
1
A
8
C
15
C
2
A
9
A
16
B
3
C
10
D
EC1
D
4
D
11
C
EC2
A
5
B
12
B
EC3
C
6
C
13
B
7
B
14
C
Total
Points
Unit B Quiz 1 - Activities 0,1, and 2
ANSWER KEY – FORM A
Multiple Choice [Each correct answer is worth 1 point… your teacher may multiply this by another factor.]
Question
Answer
Question
Answer
Question
Answer
1
B
8
B
15
B
2
D
9
A
16
C
3
C
10
EC1
D
D
4
D
11
D
EC2
A
5
C
12
A
EC3
C
6
D
13
A
7
A
14
B
Total
Points
Unit B Quiz 1 - Activities 0,1, and 2
ANSWER KEY – FORMs A and B
Open Response
1. [Each correct answer is worth 1 point.]
A
B
BB
C
E
A:
OCEANIC CRUST
B:
CONTINENTAL CRUST
C:
LITHOSPHERE
D:
MANTLE
E:
ASTHENOSPHERE
D
2. Compare and contrast the two terms in ONE of the pairs below. You can do this with a paragraph OR
with a Venn diagram. Be sure to include specific details in your answer. [A complete, accurate
answer is worth 3 points. 1 point per comparison or contrast.]
a) continental vs. oceanic crust







continental crust is less dense than oceanic crust
continental crust is above water… oceanic is below water
continental crust is very old (up to 4 billion years) while oceanic crust is relatively young (younger
than 200 million years)
continental crust is very thick (30-50 km) while oceanic crust is relatively think (5-10 km)
both continental and oceanic crust are part of the outermost layer of the earth
the Earth’s tectonic plates are made up of both continental and oceanic crust
other:
b) lithosphere vs asthenosphere





lithosphere is closer to surface than the asthenosphere…
the lithosphere is the upper part of the mantle along with the crust, while the asthenosphere is
the lower part of the mantle
lithosphere is rigid while the asthenosphere is like a stiff liquid – the asthenosphere can flow very
slowly
both the lithosphere and asthenosphere are made up of similar material but they move in very
different ways
other:
c) crust vs. mantle




the crust is the outermost layer of the earth, while the mantle is the next layer in.
the boundary between the crust and the mantle is very well defined
rocks from the mantle have a different composition than rocks from the crust
the crust is relatively thin while the mantle is relatively thick

other:
3. Explain how we know the tectonic plates are moving and what causes them to move. In your answer, use
AND UNDERLINE the terms below:
[A complete, accurate answer is worth 6 points.
crust
GPS (receivers, satellites)
mid-ocean ridge
rising magma
sea-floor spreading
Answers will vary, but should address the following key points and utilize key vocabulary terms– 1 point for each
idea and/or correct use of vocabulary term(s).

GPS shows that our location changes with time

In GPS a satellite orbiting Earth communicates with a receiver on Earth. Information gathered years ago for
a given location is different than information gathered today… showing that the actual location has moved.
This has been observed at stations all over the world over the last 10 years or so

Scientists have studied the magnetism of rocks (basalt) that make up the sea floor. They noticed an
alternating pattern of magnetic polarity in the rocks of the sea floor – which is a key piece of evidence that
the Earth’s plates are moving.

As rising magma pushes through the ocean floor at a mid-ocean ridge – it cools and new rock is formed.
The rock has the same polarity (magnetic orientation) as the Earth does at the time the magma cools. Over
time the Earth’s magnetic pole switches, and the polarity of the new rock switches too. This leads to an
alternating pattern of magnetic polarity in the rocks of the sea floor. This explanation for the matching
patterns on both sides of the mid-ocean ridge is called sea-floor spreading.

All of the oceanic crust is relatively young (less than 200 million years old) while the continental crust is
very old (up to 4 billion years)… which indicates that plates are growing / moving.

Rocks taken from the ocean floor / oceanic crust are younger near the mid-ocean ridge and older further
away from the ridge… indicating movement of Earth’s plates.

The width of the magnetic rock bands on the sea floor vary… indicating the rate of movement of the
Earth’s plates … which can vary widely depending on location.

Scientists can look at the offsets along the mid-ocean ridges to get information about the direction of plate
movement.