## OG Test 2 - Reading 5

Questions 43-52 are based on the following passage.

This passage is adapted from Geoffrey Giller ,“ Long a Mystery, How 500-Meter-High Undersea Waves Form Is Revealed.”© 2014 by Scientific American.
Some of the largest ocean waves in the world are
nearly impossible to see. Unlike other large waves,
these rollers, called internal waves, do not ride the
Lineocean surface. Instead, they move underwater ,
5undetectable without the use of satellite imagery or
sophisticated monitoring equipment. Despite their
hidden nature, internal waves are fundamental parts
of ocean water dynamics, transferring heat to the
ocean depths and bringing up cold water from below.
10And they can reach staggering heights-some as tall
as skyscrapers.
Because these waves are involved in ocean mixing
and thus the transfer of heat, understanding them is
crucial to global climate modeling, says Tom
15Peacock, a researcher at the Massachusetts Institute
of Technology. Most models fail to take internal
waves into account ." If we want to have more and
more accurate climate models, we have to be able to
capture processes such as this, "Peacock says.
20Peacock and his colleagues tried to do just that.
Their study, published in November in Geophysical
Research Letters, focused on internal waves generated
in the Luzon Strait, which separates Taiwan and the
Philippines. Internal waves in this region, thought to
25be some of the largest in the world, can reach about
500 meters high. "That s the same height as the
Freedom Tower thats just been built in New York,"
Peacock says.
Although scientists knew of this phenomenon in
30the South China Sea and beyond, they didnt know
exactly how internal waves formed. To find out,
Peacock and a team of researchers from M.I.T. and
Woods Hole Oceanographic Institution worked with
Frances National Center for Scientific Research
35using a giant facility there called the Coriolis
Platform. The rotating platform, about 15 meters
(49.2feet) in diameter, turns at variable speeds and
can simulate Earths rotation. It also has walls, which
means scientists can fill it with water and create
40accurate, large-scale simulations of various
oceanographic scenarios.
Peacock and his team built a carbon-fiber resin
scale model of the Luzon Strait, including the islands
and surrounding ocean floor topography. Then they
45filled the platform with water of varying salinity to
replicate the different densities found at the strait,
with denser, saltier water below and lighter, less
briny water above. Small particles were added to the
solution and illuminated with lights from below in
50order to track how the liquid moved. Finally, they
re-created tides using two large plungers to see how
the internal waves themselves formed.
The Luzon Straits underwater topography, with a
distinct double-ridge shape, turns out to be
55responsible for generating the underwater waves.
As the tide rises and falls and water moves through
the strait, colder, denser water is pushed up over the
ridges into warmer, less dense layers above it.
This action results in bumps of colder water trailed
60by warmer water that generate an internal wave.
As these waves move toward land, they become
steeper-much the same way waves at the beach
become taller before they hit the shore -until they
break on a continental shelf.
65The researchers were also able to devise a
mathematical model that describes the movement
and formation of these waves. Whereas the model is
specific to the Luzon Strait, it can still help
researchers understand how internal waves are
70generated in other places around the world.
Eventually, this information will be incorporated into
global climate models, making them more accurate.
"Its very clear, within the context of these [global
climate] models, that internal waves play a role in
75driving ocean circulations ," Peacock says.

Question 43

The first paragraph serves mainly to

• A explain how a scientific device is used.

• B note a common misconception about an event.

• C describe a natural phenomenon and address its importance.

• D present a recent study and summarize its findings.

Question 44

As used in line19,"capture"is closest in meaning to

• A control.

• B record.

• C secure.

• D absorb.

Question 45

According to Peacock, the ability to monitor internal waves is significant primarily because

• A it will allow scientists to verify the maximum height of such waves.

• B it will allow researchers to shift their focus to improving the quality of satellite images.

• C the study of wave patterns will enable regions to predict and prevent coastal damage.

• D the study of such waves will inform the development of key scientific models.

Question 46

Which choice provides the best evidence for the answer to the previous question?

• A Line1-2("Some...see")

• B Lines4-6("they...equipment")

• C Lines17-19("If...this")

• D Lines24-26("Internal...high")

Question 47

As used in line 65,"devise"most nearly means

• A create.

• B solve.

• C imagine.

• D begin.

Question 48

Based on information in the passage, it can reasonably be inferred that all internal waves

• A reach approximately the same height even though the locations and depths of continental shelves vary.

• B may be caused by similar factors but are influenced by the distinct topographies of different regions.

• C can be traced to inconsistencies in the tidal patterns of deep ocean water located near islands.

• D are generated by the movement of dense water over a relatively flat section of the ocean floor.

Question 49

Which choice provides the best evidence for the answer to the previous question?

• A Lines 29-31("Although...formed")

• B Lines 56-58("As the...it")

• C Lines 61-64("As these...shelf")

• D Lines 67-70("Whereas...world")

Question 50

In the graph , which isotherm displays an increase in depth below the surface during the period 19:12 to 20:24?

• A 9°C

• B 10°C

• C 11°C

• D 13°C

Question 51

Which concept is supported by the passage and by the information in the graph?

• A Internal waves cause water of varying salinity to mix.

• B Internal waves push denser water above layers of less dense water.

• C Internal waves push bands of cold water above bands of warmer water.

• D Internal waves do not rise to break the oceans surface.

Question 52

How does the graph support the author`s point that internal waves affect ocean water dynamics?

• A It demonstrates that wave movement forces warmer water down to depths that typically are colder.

• B It reveals the degree to which an internal wave affects tje destiny of deep layers of cold water.

• C It illustrates the change in surface tempreture that takes place during an isolated series of deep waves.

• D It shows that multiple waves rising near the surface of the ocean disrupt the flow of normal tides.

Questions:

• 43
• 44
• 45
• 46
• 47
• 48
• 49
• 50
• 51
• 52