Why Don’t We Get Crushed By Atmospheric Pressure?

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The air around us seems to be weightless, but it is actually exerting a lot of pressure on us. The atmosphere is made up of a lot of small molecules that, together, weigh a lot. However, the human body has evolved to withstand this pressure, so we don’t feel it. If the body were an empty shell, it would be crushed by the atmospheric pressure.

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.

Different layers of the atmosphere (Credit: Vadim Sadovski/Shutterstock)

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?

Also Read: Why Are High-Altitude Regions So Cold?

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.

Let me put this in simpler words; the human body has evolved over the years in the presence of air, so it is only fair to say that it has evolved in accordance with the pressure that is exerted upon it all the time. 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.

Also Read: Without Technology, How Did We First Learn There’s No Oxygen In Space?

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. There is no ‘cure’ for it, per se, but there are certain methods that could definitely help you open your eardrums and get the pressure back to normal. 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.

Also Read: Why Do Your Ears Pop When The Airplane Takes Off?

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References (click to expand)
  1. Why are you not crushed by atmospheric pressure?. The University of California, Santa Barbara
  2. Collapsing Can Experiment - scifun.chem.wisc.edu:80
  3. Air Exerting Pressure - mypages.iit.edu
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About the Author

Ashish is a Science graduate (Bachelor of Science) from Punjabi University (India). He spearheads the content and editorial wing of ScienceABC and manages its official Youtube channel. He’s a Harry Potter fan and tries, in vain, to use spells and charms (Accio! [insert object name]) in real life to get things done. He totally gets why JRR Tolkien would create, from scratch, a language spoken by elves, and tries to bring the same passion in everything he does. A big admirer of Richard Feynman and Nikola Tesla, he obsesses over how thoroughly science dictates every aspect of life… in this universe, at least.