Water does what it wants and
submits to few influences. It is pushed and pulled by gravity and wind. It is
moved and changed by heat and cold, and yet restrained by its defining
characteristics and when calm always presents a level surface. Water can
destroy and create. It finds an insidious path but, with knowledge and
understanding, it can be held back. Water is life and death. Water is peace and
torrent. Water is simple and profound. Water is cleansing.
Water has few external forces
that take control over its movements and abilities. Gravity is one of the
greatest of these. Gravity is a pull to a mass created by a density, the
greater the mass, the greater the pull. It can have far reaching effects like
driving ocean tides and bending light waves. It also keeps water in your
drinking glass. Gravity is what drives rivers and glaciers to flow and
raindrops and snowflakes to fall. Gravity acts on ever molecule of water as
liquid, gas or solid.
A second external force is
wind. Wind can move water against gravity and with gravity. Wind can drive waves
and direct rain. Wind can work with the many characteristics of water to make
it a powerful substance.
Temperature also influences
water. Water can change states depending on the temperature, or amount of heat
it holds. It even expands as it freezes and the molecules arrange themselves in
a crystalline manner. In its least dense state, as a gas, water is high in
heat. As a liquid it has the ability to store vast amounts of heat and even
control weather. As a dense solid, holding less heat, frozen water can change
massive landforms or cool the liquid in your glass.
Water is under constant
effects of other forces and oftentimes bends to theses effects and influences
but there are characteristics of water that provide parameters. A water
molecule has an odd shape that helps it dissolve many other substances. The
oxygen side has a negative charge and the hydrogen side is positive and when
they contact substances like salt, sugar or an acid those charges allow the
substances to dissolve. Water is a universal solvent. This electrical polarity
of the water molecule also prevents water from bonding with other substances,
for instance oils. Water is more attracted to itself than to oils so oil will
not dissolve in water. This attraction to itself is a strong characteristic of
water when seen on its surface.
An actual tension exists on
the surface of water as the molecules hold onto each other. This surface
tension has amazing holding strength. Small bugs use this characteristic of
water to their advantage and actually travel on top of water. More dense
objects when spread over a large area can also use surface tension to stay
afloat. Like a child lying on a giant water lily pad.
The electrical charge of a
water molecule has another amazing result. Something called capillary action.
Capillarity, as it can be called, is dependent on cohesion and adhesion.
Cohesion is the ability of a substance to stick to itself and adhesion is the
ability or draw of a substance to stick to a different substance. Cohesion is
what provides for water’s surface tension and adhesion is what provides for the
ability of a paper towel to pick up water. Water molecules adhere to the fibers
of the towel and pull in other molecules due to cohesive forces. More molecules
are present to adhere to the towel fibers and in turn bring even more cohesive
molecules with them until the towel is saturated. Plants are an amazing example
of using cohesive and adhesive forces. Small tubes in plants allow for the
travel of water up and down their structure. The most incredible example of
this is the Coastal Redwood, known as the tallest of trees, reaching heights
over 360 feet. Inside the plant are tubes called xylem and phloem. These small
tubes transport water, sugar and other nutrients to the plant’s body. This
transportation of water is due to the ability of water to adhere to the xylem
fibers and be drawn in much like the paper towel. Within the tube a small
meniscus will form, much like the upturned edge of water in your drinking
glass. This meniscus draws the water up the edge of the xylem and cohesion
brings more water until the force of adhesion and the force of cohesion are
counterbalanced by the gravitational force on the water column. That is why
narrow tubes will draw up a taller column of water than wider tubes, like your
drinking glass.
I battle water often as I try
to keep it from penetrating my house in unwanted ways, and yet I welcome its
presence and keep it contained in vessels and pipes. When it invades often
times it isn’t until damage is done that we are aware of its destructive force;
seeping through walls, under hardwood floors and through holes in roofs. It has
an amazing ability to find the smallest of entry points and exploit any
weakness in a barrier. Then there are times when the destructive force is all
too obvious as in the overflowing bathtub and the cracked frozen pipe that
comes alive as it thaws.
Tony
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