Test 3 Review Challenge

Dr. James and her team of geologists have been studying GPS data that shows that two plates moved apart. Which diagram shows what happened between the two plates as they moved away from each other?

• Diagram A: A new plate from underneath filled in the gap that was created by the plates moving apart.

• Diagram B: Sand and dirt filled in the gap that was created by the plates moving apart.

• Diagram C: Ocean water filled in the gap that was created by the plates moving apart.

• Diagram D: Soft, solid rock from underneath the plates rose and hardened, adding solid rock to the edges of both plates.

Answer explanation

Remember, magma (soft solid rock) from the mantle errupts as lava onto the ocean floor at mid-ocean ridges. As the hot magma touches the cold water on the ocean floor, it cools and hardens, forming Basalt. Basalt is new crust. It is constantly being created at mid-ocean ridges which pushes the older crust away from the ridge.

Fossil remains of Glossopteris (an extinct plant) have been discovered in Antarctica and Australia. The Glossopteris seed is known to be large and bulky and therefore could not have drifted or flown across the oceans to separate continents. However, now there are oceans between the Glossopteris fossils. What could explain how these fossils got so far apart?

• Antarctica and Australia are parts of different plates. The plates slowly moved far apart as soft, solid rock from underneath got added to the edges of the plates over millions of years.

• Antarctica and Australia are parts of different plates. The plates floated away from each other across the ocean.

• Antarctica and Australia are parts of different plates. The plates slowly moved apart as new plates from underneath got added between them over millions of years.

• Antarctica and Australia are parts of different plates. The plates were sometimes pushed far apart by earthquakes, and soft, solid rock from underneath got added to the edges of the plates.

Scientists often study cross sections to better understand what the inside of something looks like. If we took a cross section of a potted plant by cutting it vertically, what would the cross section look like?

• A

• B

• C

• D

Answer explanation

A cross section is a diagram that shows an object's layers. If you can't see layers, it is NOT a cross section!

Dr. Morris and her team have been using GPS to track two plates that are moving toward each other. Which diagram shows what is happening at the place where the plates are moving toward each other?

• Diagram A: Two plates are hitting each other, and the plates are breaking into pieces, creating sand.

• Diagram B: Two plates are pushing against each other, causing the edges to bend upward.

• Diagram C: One plate is going underneath the other plate and sinking into the soft rock below.

• Diagram D: One plate is going underneath the other plate and sinking into the ocean below.

Answer explanation

Diagram C shows subduction - when one plate sinks under another plate and into the mantle as the plates converge.

Earthquakes make plates move apart.

• True

• False

Answer explanation

Earthquakes don't cause any kind of plate movement (converging, diverging, or transforming)! Plate movement causes earthquakes.

Earthquakes and volcanoes are often found:

• at plate boundaries around the world

• At some plate boundaries

• In the middle of plates

• In the inner core

Patterns on this map tell us that . . .

• volcanic activity and earthquakes can cause damage to buildings and hurt people.

• volcanic activity and earthquakes happened in similar areas.

• volcanic activity and earthquakes happened in random locations all over the map.

• volcanic activity and earthquakes happened in the following order: volcanic activity, earthquake, volcanic activity, earthquake, and so on.

In the past, Africa used to be farther away from Europe than it is now (shown above). What could explain why Africa is closer to Europe now than it was before?

• Africa and Europe are parts of different plates. The plates floated toward each other across the ocean.

• Africa and Europe are parts of different plates. The plates were sometimes pushed toward each other by earthquakes, and one plate went under the other plate into soft, solid rock.

• Africa and Europe are parts of different plates. The plates slowly moved toward each other over millions of years. When the plates hit each other, they broke into smaller pieces.

• Africa and Europe are parts of different plates. The plates slowly moved toward each other as one plate went under the other plate into soft, solid rock over millions of years.

Which statement best describes what Earth’s outer layer is like underneath the surface in the image?

• Underneath both the soil and the ocean, Earth’s outer layer is made of sand and water.

• Underneath both the soil and the ocean, Earth’s outer layer is made of hard, solid rock.

• Underneath the soil, the outer layer is made of hard, solid rock. Underneath the ocean, Earth's outer layer is made of sand.

• Underneath the soil, Earth’s outer layer is made of water.

Answer explanation

Remember, Earth's outer layer is the crust. It is the top layer of Earth that makes up the continents and is underneath the oceans.

Who is the person credited with developing the theory of continental drift?

• Harry Hess
• Galileo
• Alfred Wegener
• Newton

Answer explanation

Continental drift was a theory that explained how continents shift position on Earth's surface.