Chapter Three: Seawater; It's Makeup and Movements
What are the definitions of the ebb and the flood of a tide?
The ebb is the flow away from shore and the flood is the flow toward shore.
What is the process of evaporation, condensation and return of water to the sea by way of precipitation called?
The hydrologic cycle.
What is the name of the zone of the ocean between 260 and 566 feet where only very dark violet light is able to reach.
The twilight zone.
Why are tiny dust and ash nuclei in the atmosphere important?
They allow evaporated water to form droplets and grow until they fall as rain back to the surface of the earth.
Why is the tidal effect caused by the Sun only two-fifths as strong as that caused by the Moon?
Because the Sun is 390 times farther away than the Moon.
Why is it that in the winter time, it tends to be warmer near the sea coast and colder farther inland?
Because water retains heat better than land.
The Yellow Sea appears yellow in color because of yellow clay silt carried into it by the rivers of what country?
China.
What surf height is considered to be the critical height for normal amphibious landings on an average beach?
Four feet.
Which country has built the world's most highly successful tidal energy plant?
France.
Who was the oceanographer who theorized in 1955 that a counter-current flowed beneath the Gulf Stream?
Henry Stommel.
Where does the Sargasso Sea lie?
In the North Atlantic Ocean off of the southeastern U.S. coast.
How is water significantly different than most other materials when heated and cooled?
It contracts until it's close to freezing then expands rapidly.
How has the amount of salts in the sea changed over the past few millions of years?
It has remained fairly stable over that time.
What bodies of seawater tend to have the highest concentrations of salt?
Land-locked lakes.
Which of the following statements about water is true?
Sound travels faster in water than air and increases with temperature and salinity.
Which type of breaker occurs where there is a mild and gradual shape to the beach?
Spilling Breaker.
What is the name of a long, smooth wave coming from a distant storm center?
Swell.
Which of the rivers below has the highest tidal bores in the world?
The Amazon River
Which of the following areas has relatively low tides?
The Mediterranean Sea.
What is the primary cause of the rise and fall of ocean tides?
The Moon's gravity.
What is the name of the piece of oceanographic equipment designed to free-float while remaining at any chosen depth?
The Swallow Buoy.
Which zone of the ocean has no light at all except that which is created by an object or animal?
The dark zone.
What is the color of most of the world's seawater?
Seawater is colorless.
What is considered to be the purest natural source of water?
Snow.
Which of the following minerals is found in the greatest quantity in seawater?
Sodium chloride.
What is the normal worldwide range of temperature (Fahrenheit) of upper ocean water?
32 degrees to 85 degrees.
Approximately how many elements are known to exist in seawater?
80 elements.
What percentage of sea water is made up of pure water?
95%.
What instrument is used on most Navy combatants to monitoring seawater temperature at various depths?
A bathythermograph.
What is the only other known material that has the ability to store more heat than water?
Ammonia.
What causes the Red Sea to appear red?
Red phytoplankton in the water.
What is the term used to describe when a part of a line of waves changes direction or bends because of shallower water?
Refraction.
