Chapter 15- Science

Flashcard maker : Donna Chou
Oceanography, Topex/ Posiden, sonar, Challenger, or Meteor: German reasearch ship that studied the oceans during the 1920s
Meteor
Oceanography, Topex/ Posiden, sonar, Challenger, or Meteor: Satellite used to monitor ocean surface temperatures
Topex/Posiedon
Oceanography, Topex/ Posiden, sonar, Challenger, or Meteor: Device that uses echoes to map features of the ocean floor
Sonar
Oceanography, Topex/ Posiden, sonar, Challenger, or Meteor: 1st ship to use sophisticated measuring devices to study the ocean
Challenger
Oceanography, Topex/ Posiden, sonar, Challenger, or Meteor: Scientific study of Earth’s oceans
Oceanography
Oceans on Earth have existed for ___.
almost 4.6 billion years
One possible source of Earth’s water is _____.
comet impacts
Gases emitted by volcanoes contain mostly ____.
water vapor and carbon dioxide
In Earth’s early history, water vapor in the atmosphere condensed into the ______.
oceans
Water is still being added to Earth’s hydrosphere by ______.
volcanism
The total amount of water on Earth stays the same because water molecules in the atmosphere are destroyed by ___.
ultraviolet radiation
The _____ contain 97% of the water found on Earth.
oceans
Approximately 3 percent of Earth’s water is located in the ____ of Greenland and Antarctica, and in rivers, lakes, and underground sources.
frozen ice caps
Global ___ has risen and fallen by hundreds of meters in response to warm periods and ice ages.
sea level
_____ forces that lift or lower portions of the seafloor also affect sea level.
Tectonic
Today average global sea level is slowly ____ at a rate of 1 to 2 mm per year.
rising
Why is Earth known as the blue planet?
Earth is known as the blue planet because it is 71% covered by water and looks blue from space.
What is the average depth of the oceans?
The average depth of the oceans is 3800 m.
How much of the northern hemisphere is covered by oceans?
61% of the northern hemisphere is covered by oceans.
How much of the southern hemisphere is covered by oceans?
81% of the southern hemisphere is covered by oceans.
True or False: The 3 major oceans are the Atlantic, the Pacific, and the *Arctic.*
False: Indian
True or False: The *Pacific* is Earth’s largest ocean.
true
True or False: The Atlantic Ocean extends for more than *2,000 km* from north to south.
true
True or False: North of the *antarctic* circle, the Atlantic is known as the Arctic Ocean.
False: arctic
True or False: The Indian Ocean is located mainly in the *northern* hemisphere.
False: southern
About what percentage of seawater is dissolved salts?
3.5 percent
Which of the following salts is most abundant in seawater?
sodium chloride
What is salinity?
the amount of dissolved salts in seawater
What unit is commonly used to measure the salt content of water?
parts per thousand
In addition to salts, which of these substances is dissolved in seawater?
nutrients
Which of the following would cause surface ocean water to have a higher salt content?
A. a river flowing into the ocean
B. the melting of sea ice
C. high rates of evaporation and low rates of precipitation
D. low rates of evaporation and high rates of precipitation
C. high rates of evaporation and low rates of precipitation
What evidence indicates that the salt content of ancient oceans was about the same as it is today?
comparisons of modern seashells and fossil shells
Which process does NOT add salts to seawater?
A. weathering of crustal rock
B. decay of hard- shelled sea creatures
C. volcanic gases
D. flow of rivers into the ocean
B. decay of hard- shelled sea creatures
Which process removes salt from seawater?
A. ultraviolet radiation
B. weathering of feldspars
C. evaporation of elements near arid coastal regions
D. consumption of sediments by bottom- feeding organisms
C. evaporation of elements near arid coastal regions
Sequence the stages of water- mass movement.
-Cold, salty water sinks
-Sea ice forms during the winter
-Salty water migrates along the ocean floor toward the equator
-Salt ions accumulate beneath the ice
-1. sea ice forms during winter
-2. salt ions accumulate beneath the ice
-3. cold, salty water sinks
-4. salty water migrates along the ocean floor toward the equator
Describe the rhythmic movement of a wave. What is the direction of its energy?
In a wave, water moves downward in circles that decrease in size with depth. At a depth equal to half its wavelength water movement stops. Wave energy moves steadily forward.
What is the highest point of the wave called?
The crest
What is the lowest point of a wave called?
The trough
What is the vertical distance between the highest and lowest points of a wave?
wave height
What is the horizontal difference between the top of one wave and the top of the next?
wavelength
What is the relationship between the wave speed in deep water and wavelength?
The wavelength determines the depth to which the wave disturbs the water. Wave speed increases with wavelength.
How does an ocean wave become a breaker at the shoreline?
An ocean wave becomes a breaker at the shoreline as the waves lose energy because of friction with the ocean bottom. This causes the waves to slow. Incoming wave crests gradually catch up with the slower wave crests ahead. As a result, the wave length decreases. The incoming waves become higher, steeper, and unstable, and their crests collapse forward. The collapsing waves are breakers.
Gravitational and centrifugal forces, spring tides, neap tides, tide, or tidal range: Periodic rise and fall of sea level
tide
Gravitational and centrifugal forces, spring tides, neap tides, tide, or tidal range: Difference between high tide and low tide
tidal range
Gravitational and centrifugal forces, spring tides, neap tides, tide, or tidal range: Forces exerted by the Sun and the Moon that generate tidal bulges
gravitational and centrifugal forces
Gravitational and centrifugal forces, spring tides, neap tides, tide, or tidal range: Type of tide with the highest high tides and lowest low tides.
spring tides
Gravitational and centrifugal forces, spring tides, neap tides, tide, or tidal range: Type of tide that occurs when the Sun, the Moon, and Earth form a right angle
neap tides
True or False: A current caused by difference in the temperature and salinity of ocean water is called a *gyre.*
False: density current
True or False: Surface currents are caused by *wind*
True
True or False: The gyres of the northern hemisphere circulate in a *counterclockwise* direction
False: Clockwise
True or False: Examples of warm, poleward- flowing currents are the Gulf Stream and the Kuroshio Current.
True
In addition to moving horizontally, ocean water moves _____.
vertically
The upward motion of ocean water is called _____.
upwelling
Upwelling waters originate from the bottom of the ocean and are ____.
cold
Areas of upwelling exist mainly off the western coast of continents in the _____ belts.
trade-wind
The trade winds blow surface water ___, and the surface water is replaced by upwelling deep water.
offshore
Upwelling waters are rich in _____, which support abundant marine life populations.
nutrients

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