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Atmospheric
Pressure
Why Don’t We Get Crushed By
Atmospheric Pressure?
Ashish
Let me tell you right from the
start, we’re under a lot of pressure.
As humans, there are many
types of pressure that one has to look out for in their lives, but there is
this one pressure that bears down on every single human being on Earth,
including Hulk, Iron Man and Captain America.
The air that surrounds us may seem
to be absolutely weightless, but it’s far from being so. Why do we assume that
air is weightless?
Does it not have the right to some
weight of its own? After all, the atmosphere is a part of the planet, and it
contains a number of gases that are present in differing amounts.
The Atmosphere
Air consists of an incredibly large
number of molecules. Although these molecules are very small, they are
‘respectable’ enough to have some weight of their own.
Although it’s true that a single
molecule is amazingly light and seemingly non-existent, you may feel a
bit amazed when I tell you that many air molecules are weighing down on
you right now, at this very moment.
Essentially, we are talking
about a large number of air molecules that are pretty light individually, but
become quite ‘weighty’ in great numbers.
How does it feel when you lift
something very heavy on your shoulders or head? You feel a pressure weighing
down on you, right?
Atmospheric pressure acts in
basically the same way. Thousands of air molecules weigh down on you all
the time.
In fact, the standard value of
atmospheric pressure is 14.7 pounds per square inch at sea level. To put that
in perspective, it’s like holding a small car on your head all the time.
So, how come we don’t feel it?
Equilibrium: The
Great Equalizer
The air particles around you exert
a certain amount of pressure on your entire body, but what’s interesting is
that the same amount of pressure is exerted back onto the air molecules by the
insides of the body, thereby achieving a state of equilibrium.
If the human body were an empty
shell, i.e., if it didn’t contain the fabulous assortment of organs, bones,
muscles, blood and other such things, then it would have popped like a tin can
under our atmospheric pressure. However, that doesn’t happen.
This essentially implies that there
is a certain equalization of pressures involved in this case, which is why
there is no pressure difference and why we don’t feel ‘burdened down by air’.
The pressure of air that is present
outside your body is the same as that of the air present ‘inside’ your body.
The air that is constantly present
in your lungs, ears and nose has the same atmospheric pressure as the air on
the outside of your ears, nose, and chest.
Since there is no pressure
difference, we don’t feel anything at all, as far as atmospheric pressure is
concerned.
When There is a
Pressure Difference…
You understand by now that you
don’t feel the atmospheric pressure due to an absence of a pressure difference
between the external air and the air that’s inside your body, which we’ll
call ‘internal air’.
However, what if there is a
pressure difference? Will something truly awful happen? How rare is the
occurrence of a pressure difference?
You may be a wee bit surprised to
know that the occurrence of these pressure changes is actually quite
commonplace. You may experience it often if you are a frequent flier. Getting
my drift?
You know that funny feeling when
your eardrums seem to ‘close’ themselves when your plane takes off or lands?
What about when you enter a long tunnel or exit it?
The popping of the ear is directly associated with a
change in the external and internal air pressure.
You see, when your aircraft is on the runway, the
pressure in your ear is the same as the pressure in the aircraft’s cabin.
However, as you take off and go high into the skies, an
inequality in the external and internal pressure develops, and your ears seem
to shut themselves off.
Having a
conversation in such conditions isn’t advised, especially if you’re trying to
make personal or professional ties.
There
are many other instances of changing air pressure, most of which seem to
primarily affect the nose and ear.
One such technique involves closing both the nostrils and mouth,
and then gently blowing out air through the nose. Big yawns also help to
‘un-pop’ the ears.
We can’t be thankful enough for the wonders that
nature presents all around us.
It works in mysterious ways and balances every
variable in its ambit impressively to ensures that all the natural conditions
are stacked up in a way that sustains and progresses life on Earth.
Ashish is a
Science graduate (Bachelor of Science) from Punjabi University (India). He
spends a lot of time watching movies, and an awful lot more time discussing
them. He likes Harry Potter and the Avengers, and obsesses over how thoroughly
Science dictates every aspect of life… in this universe, at least.
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