Download Earth`s atmosphere is pressing against each square inch of you with

Earth's atmosphere is pressing against each
square inch of you with a force of 1 kilogram per
square centimeter (14.7 pounds per square inch).
The force on 1,000 square centimeters
(a little larger than a square foot) is
about a ton!
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Why doesn't all that pressure squash
me?
Remember that you have air inside your body too, that air
balances out the pressure outside so you stay nice and firm
and not squishy.
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Atmospheric
Pressure:
is the pressure the air
exerts as gravity pulls it
towards the centre of
Earth.
At ground level, the
average atmospheric
pressure is approximately
100 kPa. The pressure
decreases at higher
altitudes. Pressure varies
from the average of each
altitude.
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Weather forecasters measure air
pressure with a barometer.
Barometers are used to measure the current air pressure at a
particular location in "inches of mercury" or in "millibars" (mb).
A measurement of 29.92 inches of mercury is equivalent
to 1013.25 millibars.
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Air pressure can tell us about what kind of
weather to expect as well.
If a high pressure system is on its way, often
you can expect cooler temperatures and clear
skies.
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If a low pressure system is coming, then look for
warmer weather, storms and rain. 6
In this first diagram there is no horizontal temperature or
pressure gradient and therefore no wind. Atmospheric pressure
decreases with altitude as depicted by the drawn isobars (1000
to 980 millibars).
http://www.physicalgeography.net/fundamentals/7o.html
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In the second the potential for solar heating is added which
creates contrasting surface areas of temperature and
atmospheric pressure . The area to the right receives more
solar radiation and the air begins to warm from heat energy
transferred from the ground. The vertical distance between the
isobars becomes greater as the air rises. To the far left, less
radiation is received because of the presence of cloud, and this
area becomes relatively cooler than the area to the right. In the
upper atmosphere, a pressure gradient begins to form because
of the rising air and upward spreading of the isobars. The air
then begins to flow in the upper atmosphere from high pressure
to low pressure.
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The above diagram shows the full circulation system in action. Beneath the upper atmosphere
high is a thermal low pressure center created from the heating of the ground surface. Below
the upper atmosphere low is a thermal high created by the relatively cooler air temperatures
and enhanced by the descending air from above. Surface air temperatures are cooler here
because of the obstruction of shortwave radiation absorption at the Earth's surface by the
cloud. At the surface, the wind blows from the high to the low pressure. Once at the low, the
wind rises up to the upper air high pressure system because of thermal buoyancy and outflow in
the upper atmosphere. From the upper high, the air then travels to the upper air low, and then
back down to the surface high to complete the circulation cell. The circulation cell is a closed
system that redistributes air in an equitable manner. It is driven by the greater heating of the
surface air in the right of the diagram.
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The straw works because we use
our mouth to reduce the pressure
over the fluid inside the straw.
The pressure over the rest of the
liquid in the glass continues to be
exerted and, because it is higher
than the pressure over the liquid
inside the straw, the net effect is
for the liquid to be forced from
the area of higher pressure to the
area of lower pressure.
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Bernoulli's Principle states that:
Where the speed of a fluid is high, the pressure is low,
and where the speed of a fluid is low, the pressure is
high.
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