Destructive Mother Nature on
Earth
Wind: Scientist defines wind as air in motion. The
term is usually applied to the natural horizontal motion of the atmosphere;
motion in a vertical, or nearly vertical, direction is called a current.
Winds are produced by differences in atmospheric pressure, which are
primarily attributable to differences in temperature. Variations in
the distribution of pressure and temperature are caused largely by unequal
distribution of heat from the sun, together with differences in the
thermal properties of land and ocean surfaces. When the temperatures
of adjacent regions become unequal, the warmer air tends to rise and
flow over the colder, heavier air. Winds initiated in this way are usually
greatly modified by the earth's rotation. Winds may be classified into
four major types: the prevailing winds, the seasonal winds, the local
winds, and the cyclonic and anticyclone winds.
Rain: Scientists define rain as precipitation of liquid
drops of water. Raindrops generally have a diameter greater than 0.5
mm (0.02 in). They range in size up to about 3 mm (about 0.13 in) in
diameter, and their rate of fall increases, up to 7.6 m (25 ft) per
sec with their size. Larger drops tend to be flattened and broken into
smaller drops by rapid fall through the air. The precipitation of smaller
drops, called drizzle, often severely restricts visibility but usually
does not produce significant accumulations of water.
Amount or volume of rainfall is expressed as the depth of water that
collects on a flat surface, and is measured in a rain gauge to the nearest
0.25 mm (0.01 in). Rainfall is classified as light if not more than
2.5 mm (0.10 in) per hr, heavy if more than 7.50 mm (more than 0.30
in) per hr, and moderate if between these limits.
Snow: which to a certain limit is a natural beauty
itself. Beyond limit this natural beauty becomes destructive when it
crosses the limit. Too much windy sometimes bring destruction. Too much
rain brings floods and too much snow stop commute.
Hurricanes: Scientists define hurricanes name applied
to migratory tropical cyclones that originate over oceans in certain
regions near the equator, and particularly to those arising in the West
Indian region, including the Caribbean Sea and the Gulf of Mexico. Hurricane-type
cyclones in the western Pacific are known as typhoons.
Cyclones: According to scientists cyclone in strict
meteorological terminology, an area of low atmospheric pressure surrounded
by a wind system blowing, in the northern hemisphere, in a counterclockwise
direction. A corresponding high-pressure area with clockwise winds is
known as an anticyclone. In the southern hemisphere these wind directions
are reversed. Cyclones are commonly called lows and anticyclones highs.
The term cyclone has often been more loosely applied to a storm and
disturbance attending such pressure systems, particularly the violent
tropical hurricane and the typhoon, which center on areas of unusually
low pressure.
Tornados: Scientists define tornados as violently rotating
column of air extending from within a thundercloud down to ground level.
The strongest tornadoes may sweep houses from their foundations, destroy
brick buildings, toss cars and school buses through the air, and even
lift railroad cars from their tracks. Tornadoes vary in diameter from
tens of meters to nearly 2 km (1 mi), with an average diameter of about
50 m (160 ft). Most tornadoes in the northern hemisphere create winds
that blow counterclockwise around a center of extremely low atmospheric
pressure. In the southern hemisphere the winds generally blow clockwise.
Peak wind speeds can range from near 120 km/h (75 mph) to almost 500
km/h (300 mph). The forward motion of a tornado can range from a near
standstill to almost 110 km/h (70 mph).
A tornado becomes visible when a condensation funnel made of water
vapor (a funnel cloud) forms in extreme low pressures, or when the tornado
lofts dust, dirt, and debris upward from the ground. A mature tornado
may be columnar or tilted, narrow or broad—sometimes so broad
that it appears as if the parent thundercloud itself had descended to
ground level. Some tornadoes resemble a swaying elephant's trunk. Others,
especially very violent ones, may break into several intense suction
vortices—intense swirling masses of air—each of which rotates
near the parent tornado. A suction vortex may be only a few meters in
diameter, and thus can destroy one house while leaving a neighboring
house relatively unscathed.
Earthquakes: Scientists define earthquakes as shaking
of the Earth’s surface caused by rapid movement of the Earth’s
rocky outer layer. Earthquakes occur when energy stored within the Earth,
usually in the form of strain in rocks, suddenly releases. This energy
is transmitted to the surface of the Earth by earthquake waves. The
study of earthquakes and the waves they create is called seismology
(from the Greek seismos, “to shake”). Scientists who study
earthquakes are called seismologists.
The destruction an earthquake causes depends on its magnitude and
duration, or the amount of shaking that occurs. A structure’s
design and the materials used in its construction also affect the amount
of damage the structure incurs. Earthquakes vary from small, imperceptible
shaking to large shocks felt over thousands of kilometers. Earthquakes
can deform the ground, make buildings and other structures collapse,
and create tsunamis (large sea waves). Lives may be lost in the resulting
destruction.
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