Water is one of
the essentials of life. Almost none of the life forms on earth could
exist without it. It is the most well known and prevalent liquid on
earth. It covers more than 70% of earth's surface. Most of the
living body tissue of humans is made up of water and it is a key
component of the tissues of most other living beings on the face of
the earth.
Water is the most abundant compound in the
human body and is necessary for the digestion of food, for the
transport of food to the tissues, for the elimination of body
wastes, for the circulation of body fluids (like blood and lymph),
for a lubricant in the joints and internal organs - keeping them
moist, permitting the passage of substances between the cells and
blood vessels - and for the regulation of body temperature. Water is
part of the blood system holding dissolved minerals, like calcium
and magnesium in solution, making them available to the body tissues
when they an required for proper health. To function properly, the
human body requires between one and seven
liters
of water per
day
to avoid
dehydration.
Water is known
as "the universal solvent", capable of dissolving most salts,
however is a poor solvent for proteins and other complex organic
substances. This allows liquid water to transport nutrient elements
to and within living cells without dissolving and destroying the
organic molecules of which cells are made. In fact, all known forms
of life are dependent on water for their existence.
Water's physical
properties allow it to serve both as a heat-transfer medium (e.g.,
ice for cooling and steam for heating) and as a temperature
regulator (the water in lakes and oceans helps regulate the
climate). Water absorbs infrared radiation and as a result plays a
crucial role in the atmospheric greenhouse effect helping to trap
solar radiation within earth's atmosphere and allowing for
maintaining a fairly steady surface temperature on earth. One of the
primary things looked for by scientists searching for life on other
planets is the existence of water.
Water is considered a purifier in most
religions, including
Christianity,
Islam,
Judaism,
and
Shinto.
Photo Credit:US National Oceanic and
Atmospheric Administration
With
all of the importance of water to life on Earth, human culture
around the world preserves the tradition of a terrible destruction
wreaked on the world through the awesome powers of water unleashed
against man and civilization. Almost every culture on Earth includes
an ancient flood story. Details vary, but the basic plot is the
same: Deluge kills all but a lucky few. The story most familiar to
many people is the biblical account of Noah and his Ark. The Book of
Genesis tells how “God saw that the wickedness of man was great” and
decided to destroy all of creation. Only Noah, “who found grace in
the eyes of the Lord,” his family, and the animals aboard the ark
survived to repopulate the planet. Another ancient Middle Eastern
tradition is the Babylonian epic of Gilgamesh, a king who embarked
on a journey to find the secret of immortality. Along the way, he
met Utnapishtim, survivor of a great flood sent by the gods. Warned
by Enki, the water god, Utnapishtim built a boat and saved his
family and friends, along with artisans, animals, and precious
metals. Ancient Greeks and Romans grew up with the story of
Deucalion and Pyhrra, who saved their children and a collection of
animals by boarding a vessel shaped like a giant box. European
explorers in the Americas were startled by Indian legends that
sounded similar to the story of Noah. In Chinese ancient
mythology the
ancient Chinese ruler
Da Yu (Yu the great) spent ten years to control a deluge which
swept out most of the ancient China at that time. He was aided by
the goddess
Nuwa who literally "fixed" the "broken" sky through which huge
rains were pouring.
The destructive power of water is still with
us today. The cataclysmal tsunami that hit Southern Asia at the end
of December. 2004 taking a terrible death toll of about 310,000
lives was probably the deadliest tsunami in history! The massive
waves caused by undersea earthquakes and volcano eruptions cause
tidal waves to speed across the sea. When they approach shallow
water along a coast, they are slowed, causing their length to
shorten and their height to rise sometimes as high as 100 ft (30 m).
When they break, they often destroy piers, buildings, and beaches
and take human life.
Water can inflict damage in other ways as
well. Flooding happens during heavy rains, when rivers overflow,
when ocean waves come onshore, when snow melts too fast or when dams
or levees break. Flooding may be only a few inches of water or it
may cover a house to the rooftop. Floods that happen very quickly
are called flashfloods. Flooding is the most common of all natural
hazards all around the world.
In
the United States, an average of 100 people lose their lives in
floods annually, with flood damage averaging more than $2 billion.
The Midwest's "Great Flood of 1993" cost 48 lives and more than $12
billion. Flash floods are the number one weather-related killer in
the United States—2,200 deaths in Johnstown, Pennsylvania, May 31,
1889; 238 fatalities in Rapid City, South Dakota, June 9, 1972; 140
killed in the Big Thompson Canyon near Denver July 31, 1976; 26 dead
in Shadyside, Ohio, June 14, 1990.
On a much more catastrophic scale, China's
Yellow River, over the centuries, has killed more people than any
other river in the world. In 1887 flooding killed nearly two million
people, in 1931 the death toll was almost four million, and in 1938
it was almost one million.
In this section, we will learn what causes
these terrible water disasters and how we can protect ourselves from
them and recover from their devastating destruction.
Sources:
http://www.answers.com/water
http://www.umanitoba.ca/institutes/fisheries/waternot.html
http://www.internethealthlibrary.com/Environmental-Health/WaterTheEssentialNutrient.htm
http://www.nationalgeographic.com/blacksea/ax/frame.html
http://en.wikipedia.org/wiki/Deluge_(mythology)
http://www.answers.com/tsunami
http://www.pbs.org/wnet/savageearth/tsunami/
http://www.drgeorgepc.com/TsunamiImpactSociety.html
http://www.noaa.gov/floods.html
http://www.pbs.org/wgbh/nova/flood/deluge.html
