Just how strong is the Air pressure

[AshUchiha]

.

So, how does Air Pressure 'works' on Earth.
Would this right to say that, the air molecules present in the atmosphere are forced down due to gravity and thus applies force on every object downwards towards the Earth's core thus causing Air pressure?.

Another question I would like to know the answer of , is how do we even maintain stability at such intense amount of force acting on us everytime?
I mean our body exerts force from the inside resisting us from Crushing due to Air pressure, what about our own gravity which is trying to collapse ourself from the inside. How are we resisting that?

Also, I've heard that after coming back from the space you're bone density is lessened and other factors happen causing you to get weak. So if we have less inertia we can't resist much to Air resistance, so can I expect that if someone/something with very low inertia is expected to get crushed by the Air pressure? If this statement is true then I guess we will get daily reports of "Air Crush", but it's not true.So how??

 

[Simon Bridge]

Air particles are warm so they jiggle about, they bump into things, transferring momentum, this bumping is experienced as air pressure.
The Earth has air at all because gravity can hold it down.

Our own body produces enough internal pressure to oppose the pressure of the air and our own gravity ... our own gravity is easily balanced by electrosctatic repulsion between atoms and molecules just like you don't fall through the floor.

Inertia has nothing to do with resisting air pressure... reduced bone density can make your bones more brittle, so you could have a hard time standing against gravity. Also see oesteoporosis.

 

[phinds]

.

So, how does Air Pressure 'works' on Earth.
Would this right to say that, the air molecules present in the atmosphere are forced down due to gravity and thus applies force on every object downwards towards the Earth's core thus causing Air pressure?.

No, air pressure is uniform in all directions, not just downwards.

Another question I would like to know the answer of , is how do we even maintain stability at such intense amount of force acting on us everytime?
I mean our body exerts force from the inside resisting us from Crushing due to Air pressure, what about our own gravity which is trying to collapse ourself from the inside. How are we resisting that?

We evolved in it and our bodies are completely accustomed to it.

Also, I've heard that after coming back from the space you're bone density is lessened and other factors happen causing you to get weak.

true

So if we have less inertia we can't resist much to Air resistance, so can I expect that if someone/something with very low inertia is expected to get crushed by the Air pressure? If this statement is true then I guess we will get daily reports of "Air Crush", but it's not true.So how??

inertia is something totally different and has nothing to do with air pressure or bone density

 

[Simon Bridge]

Air pressure decreases with height... the pressure from above is less than the pressure from below. If the difference (times area) is more than the weight of the object, it is said to float. The effect is more pronounced in denser fluids like water... over small distances the air pressure can be treated as uniform in all directions.
Air pressure can also vary with the weather.

 

[DaveC426913]

Another question I would like to know the answer of , is how do we even maintain stability at such intense amount of force acting on us everytime?
I mean our body exerts force from the inside resisting us from Crushing due to Air pressure,

Because things created upon the Earth do not do so by starting off with a vacuum inside. They start off in the presence of normal air pressure (or, sometimes, a lot more pressure).

By analogy, if you took a flat piece of paper and origami'ed it into a closed box, you would not expect it to suddenly implode.

what about our own gravity which is trying to collapse ourself from the inside. How are we resisting that?

The gravitational force of a 50kg object is very, very small.

 

[|Glitch|]

So, how does Air Pressure 'works' on Earth.
Would this right to say that, the air molecules present in the atmosphere are forced down due to gravity and thus applies force on every object downwards towards the Earth's core thus causing Air pressure?.

Do not forget to take into account the rotation of the planet, which causes winds. If you were in a room, with no wind, at sea level, you would experience 14.7 pounds of pressure per square inch. Not just downward, but from every direction.

Another question I would like to know the answer of , is how do we even maintain stability at such intense amount of force acting on us everytime?
I mean our body exerts force from the inside resisting us from Crushing due to Air pressure, what about our own gravity which is trying to collapse ourself from the inside. How are we resisting that?

Our biology has evolved to the point where it can adapt to a particular environment. We have vertebrae and internal bones, instead of an exoskeleton, to deal with 9.8 m/s². If you really want to know how we evolved to resist one atmospheric pressure or one gravity, then you will need to study 540 million years of biological evolution.

Also, I've heard that after coming back from the space you're bone density is lessened and other factors happen causing you to get weak. So if we have less inertia we can't resist much to Air resistance, so can I expect that if someone/something with very low inertia is expected to get crushed by the Air pressure? If this statement is true then I guess we will get daily reports of "Air Crush", but it's not true.So how??

That is true. Long exposure to a weightless environment causes loss of bone density, and certain muscles begin to atrophy because they are not being used. Legs, for example, are rarely used in a weightless environment. Another serious factor, once we leave low-Earth orbit, will be solar and cosmic radiation. Biology and that kind of high energy radiation typically do not get along. They are already being subjected to the same 14.7 pounds per square inch on the ISS that you or I are subjected to at sea level.

 

[AshUchiha]

Inertia has nothing to do with resisting air pressure... reduced bone density can make your bones more brittle, so you could have a hard time standing against gravity. Also see oesteoporosis.

But inertia is the force exerted by the body to remain at the state of rest , resisting external forces. So Considering Air pressure as the external force isn't our inertia too acting against us being crushed by it?

 

[AshUchiha]

Our own body produces enough internal pressure to oppose the pressure of the air and our own gravity ... our own gravity is easily balanced by electrosctatic repulsion between atoms and molecules just like you don't fall through the floor.

Can you explain it more clearly?, about how we resist our own gravity.

We evolved in it and our bodies are completely accustomed to it.

So, Is there any specific ratio of how much the 'Inner gravity' would be according to the object's mass. We evolved to it, so can I say that our ancestors had a hard time facing with gravity?

Air particles are warm so they jiggle about, they bump into things, transferring momentum, this bumping is experienced as air pressure.
The Earth has air at all because gravity can hold it down.

If the cause of "jiggle effect" of Air particle due to exposure to heat, then would there be no Air pressure if there is no source of heat ?

 

[phinds]

So, Is there any specific ratio of how much the 'Inner gravity' would be according to the object's mass. We evolved to it, so can I say that our ancestors had a hard time facing with gravity?

You keep talking about gravity when I think you mean pressure, and no, our ancestors did not have any problem with either one. The evolved IN it, after all.

 

[rootone]

As others have said, life on this planet including human life, has evolved to be adapted to the Earth environment.
The environment includes atmospheric pressure, gravity, and other things.
The prevailing atmospheric composition would be another one, as would be the solar radiation level, and probably more as well.

 

[guywithdoubts]

how do we even maintain stability at such intense amount of force acting on us everytime?

It really isn't so intense. The Venera landers on Venus got crushed (and melted, but that's a different story) after a few hours on surface because the Venusian atmosphere is so much denser than ours. Keep in mind the gravity there is pretty much the same as here, so just focus on air density. Same thing would happen to you if you went down the ocean. You wouldn't survive in either environment. Structurally, we're perfectly built for living here. The strength of the materials in our body and their shape is just right.

If the cause of "jiggle effect" of Air particle due to exposure to heat, then would there be no Air pressure if there is no source of heat ?

That sounds like an absolute-zero scenario, which is not possible.

 

[Chronos]

An astronaut in space is still surrounded by air just like s/he is on earth. In fact, the air pressure maintained in the ISS, or a space suit, is comparable to atmospheric pressure on earth. Human beings do not react well to exposure to a vacuum. Unpleasant things occur, like ebullism and severe flatulence.

 

[AshUchiha]

You keep talking about gravity when I think you mean pressure, and no, our ancestors did not have any problem with either one. The evolved IN it, after all.

No sir, the one which you quoted was assuming if there is any specific ratio of an object's mass and it's own gravity. Or Would saying this be correct that Our mass M ∝ Our own gravity. And I see, we evolved IN it.

 

[AshUchiha]

An astronaut in space is still surrounded by air just like s/he is on earth. In fact, the air pressure maintained in the ISS, or a space suit, is comparable to atmospheric pressure on earth. Human beings do not react well to exposure to a vacuum. Unpleasant things occur, like ebullism and severe flatulence.

I thought there is no gas present in space , it's totally empty except the Celestial objects and gases near these objects. And yes I've heard about how "human" would react to direct exposure to Vacuum, thanks for reminding me though

 

[rootone]

="AshUchiha, post: 5067692, member: 548974" And I see, we evolved IN it.

Yes we, humans and other stuff, evolved in the environment that we are in.
We could imagine living somewhere else, like Mars, but why really?.
I do not see a real possibiilty of interstellar 'colonisation', for Homo Sapiens, but I am prepared to be wrong about that.

 

[AshUchiha]

Well, there isn't any specific proofs for that though #rootone

 

[phinds]

Well, there isn't any specific proofs for that though #rootone

No, you can't prove a negative. If you want to colonize a planet other than Earth, even one in out own solar system, you can certainly hypothesize that it can be done but unless you can prove it, or come very close, you are wasting your time.

 

[DaveC426913]

Can you explain it more clearly?, about how we resist our own gravity.

So, Is there any specific ratio of how much the 'Inner gravity' would be according to the object's mass. We evolved to it, so can I say that our ancestors had a hard time facing with gravity?

It is true. Your body is under the influence of the gravity caused by your mass. It is pulling you inward.
But consider: so is a feather in your hand. Or ping pong ball, or paperclip. They are all attracted toward you by your own gravity.

Do you see any of them flying toward your body and sticking to your stomach?
No. Because the gravity from a mass of human scale is vanishingly tiny. It's measurable, but you'd need instruments to detect it.

Gravitational attraction is not a significant force to contend with until you are dealing with objects the size of city blocks or more.

 

[rootone]

Well, there isn't any specific proofs for that though #rootone

No there are not.
Your application for intergalactic social support has been accepted, and we will try to find suitable housing for you.

 

[AshUchiha]

Do you see any of them flying toward your body and sticking to your stomach?
No. Because the gravity from a mass of human scale is vanishingly tiny. It's measurable, but you'd need instruments to detect it.

You mean to say our own gravity is slowly replinishing!?

 

[phinds]

You mean to say our own gravity is slowly replinishing!?

What are you talking about ?

 

[DaveC426913]

You mean to say our own gravity is slowly replinishing!?

What are you talking about ?

+1 phinds.

Replenishing means refilling or returning to a former value. I don't know how you got that from what I said. The gravity is not reducing or returning.

 

[AshUchiha]

+1 phinds.

Replenishing means refilling or returning to a former value. I don't know how you got that from what I said. The gravity is not reducing or returning.

Goodness! So in the absence of Air pressure am I supposed to explode ??

 

[rootone]

Yes if you were suddenly teleported to outer space you would explode.
Well it would be more of gradually 'puffing up' as gases within your body seek equilibrium with the almost vacuum of space.
Some liquids would become gaseous, your blood would boil at normal blood temperature.
You would start leaking all over with small eruptions here and there as the gases break through your skin.
Severe flatulence may be expected too.

 

[AshUchiha]

I guess that's why they supply with a space suit which applies force on us every time while we wear it, to form an equilibrium, Is this right?

If it is, then what if they land up to a planet which has almost the same gravity as of Earth, they will implode?

 

[rootone]

Yes that's right.
The primary purpose of a space suit is to keep your body in a survivable environment.
Air pressure is the most important consideration, but there are others such a temperature.

I'm not sure what you mean about the imploding, but if instead of bring teleported to outer space you were teleported to a planet with extreme gravity/atmospheric pressure compared to the surface of Earth, you would be crushed.

 

[russ_watters]

Yes if you were suddenly teleported to outer space you would explode.
Well it would be more of gradually 'puffing up' as gases within your body seek equilibrium with the almost vacuum of space.
Some liquids would become gaseous, your blood would boil at normal blood temperature.
You would start leaking all over with small eruptions here and there as the gases break through your skin.
Severe flatulence may be expected too.

And by the way, some of those effects can happen if you scuba dive wrong, too.

 

[rootone]

Yeah I was about to add that, but you got there first.
.. and there is only so far down a human being can go in the ocean before any kind of suit will not prevent them from being crushed.
Something stronger is needed, like a submarine, to provide a survivable environment.

... but there are creatures in the deep ocean which have adapted to it, and these would not survive if they were brought to the surface.

 

[DaveC426913]

I guess that's why they supply with a space suit which applies force on us every time while we wear it, to form an equilibrium, Is this right?

Well, yes. Though the "force" is a flexible shell that contains air at less than 1 atmosphere of pressure. It does not "actively" compress us. See belowq

If it is, then what if they land up to a planet which has almost the same gravity as of Earth, they will implode?

No. Same reason an astronaut in a spacesuit here on Earth doesn't implode. It's in equilibrium. The suit is not applying a force so much as it is containing an atmosphere. If atmo outside the suit balances atmo inside the suit, then they are in equilibrium, and the suit just stays slack.

 

[AshUchiha]

No. Same reason an astronaut in a spacesuit here on Earth doesn't implode. It's in equilibrium. The suit is not applying a force so much as it is containing an atmosphere. If atmo outside the suit balances atmo inside the suit, then they are in equilibrium, and the suit just stays slack.

Confusing, it can maintain us not exploding at the outer space. It means it's nearly as equal to our atmosphere pressure. If this statement is true, then if that man comes to Earth, the force exerted by the suit + atmospheric pressure would crush him down??

If my statement, is wrong. Then does the spacesuit applies the minimum force to maintain a stable shape {of us} ??

 

[rootone]

The space suit, or a submarine, serve the function of keeping a human body in a safe shell, an environment which they can survive in.
Exposure to the environment outside the shell is lethal, so most people don't even think about trying it.

 

[AshUchiha]

The space suit, or a submarine, serve the function of keeping a human body in a safe shell, an environment which they can survive in.
Exposure to the environment outside the shell is lethal, so most people don't even think about trying it.

So my contradiction is correct?

 

[rootone]

I'm not sure what the contradiction is.
The space suit or similar is providing air pressure which is similar to that at the surface of Earth.
Therefore the human being inside it is not exposed to pressure conditions which would cause physical breakdown and deformation of their body organs in a number of different ways.
Yes you could describe that as applying a force in that the pressurisation of the suit is achieved by using compressed air bottles, or a pump, but I don't see how that's very relevant, to the occupant, they are only interested in the suit providing a survivable environent
I guess that people who design space suits though - it must be for them a matter of great importance that the materials used are strong enough to maintain their integrity when subjected extreme differentials of pressure.

 

[AshUchiha]

I see, I've heard there are "chambers" which have very less gravity{which can make us float in that object"} I would like to know how it achieved?

 

[phinds]

I see, I've heard there are "chambers" which have very less gravity{which can make us float in that object"} I would like to know how it achieved?

What ARE you talking about? Do you mean swimming pools that are used to train astronauts? They are just swimming pools. The spacesuits are set to provide neutral buoyancy, but gravity is still there. Buoyancy and gravity are not the same thing.

 

[AshUchiha]

What ARE you talking about? Do you mean swimming pools that are used to train astronauts? They are just swimming pools. The spacesuits are set to provide neutral buoyancy, but gravity is still there. Buoyancy and gravity are not the same thing.

Exactly sir!, I see, so is it impossible to have "zero gravity"?

 

[rootone]

I see, I've heard there are "chambers" which have very less gravity{which can make us float in that object"} I would like to know how it achieved?

You might be thinking of aircraft which are sometimes used to simulate weightlessness.
The plane goes into a steep dive calculated such that occupants are in free fall towards the earth, effectively making them weightless.
This can only be done for a short period of time because the plane has to end the dive, at this point the occupants pay for the weightlessness by experiencing 2 or 3 times their normal weight.

 

[phinds]

Exactly sir!, I see, so is it impossible to have "zero gravity"?

I'm not sure if you are confusing zero gravity with weightlessness. You can, as rootone pointed out, have weightlessness in a gravitational field if you are in free fall.

 

[AshUchiha]

Weightlessness is almost impossible?? Mass can neither be created nor be destroyed, and our Earth's gravity hasn't replenished, so we are facing gravity always {While on Earth}, And as

Weight= Mass+Gravity, one which cannot be destroyed and one which is always present. So I wonder how can we counter these and attain weightlessness?

Also Free fall towards Earth, would increase our Acceleration due to g, so gravity is acting on us. So what you might be explaining would be just "near" to weightlessness ?

 

[phinds]

Also Free fall towards Earth, would increase our Acceleration due to g, so gravity is acting on us. So what you might be explaining would be just "near" to weightlessness ?

No, it is exactly weightlessness.

 

[virgil1612]

Weightlessness is almost impossible?? Mass can neither be created nor be destroyed, and our Earth's gravity hasn't replenished, so we are facing gravity always {While on Earth}, And as

Weight= Mass+Gravity, one which cannot be destroyed and one which is always present. So I wonder how can we counter these and attain weightlessness?

Also Free fall towards Earth, would increase our Acceleration due to g, so gravity is acting on us. So what you might be explaining would be just "near" to weightlessness ?

You are weightless (notice that no one is saying massless) if you don't feel the floor under your feet. This is happening if you are in an elevator or aircraft that are in free fall, if you are completely submerged in a pool, etc. It is exactly the same thing as if you would orbit the Earth in a satellite.

 

[phinds]

You are weightless (notice that no one is saying massless) if you don't feel the floor under your feet. This is happening if you are in an elevator or aircraft that are in free fall, if you are completely submerged in a pool, etc. It is exactly the same thing as if you would orbit the Earth in a satellite.

No, being in a pool is not weightless, nor does it feel so. Float on your back in a pool sometime an lift your arm up. It will not feel weightless at all, whereas if you are in orbit, you really are weightless. As I said previously, being in a pool can provide neutral buoyancy but not weightlessness.

 

[virgil1612]

No, being in a pool is not weightless, nor does it feel so. Float on your back in a pool sometime an lift your arm up. It will not feel weightless at all, whereas if you are in orbit, you really are weightless. As I said previously, being in a pool can provide neutral buoyancy but not weightlessness.

Well, of course it's not exact weightlessness. But it's pretty close. And about lifting the arm, I was mentioning that you should be "completely submerged". But of course it's not the real thing. But hey, it's good enough for the astronauts!

 

[AshUchiha]

But weight is the addition of mass and gravity , so I must include it right?. I guess by weightlessness you mean having no opposing force on us preventing us from falling to the core of the Earth. Is that what you meant by that?

 

[AshUchiha]

You are weightless (notice that no one is saying massless) if you don't feel the floor under your feet. This is happening if you are in an elevator or aircraft that are in free fall, if you are completely submerged in a pool, etc. It is exactly the same thing as if you would orbit the Earth in a satellite.

So I was right, but it can't be called weightlessness, I would rather recommend naming it "feel as if weightless"

 

[virgil1612]

So I was right, but it can't be called weightlessness, I would rather recommend naming it "feel as if weightless"

In Physics books they are talking about 'real weight' and 'apparent weight'. The real weight is mg, so for this to be zero you would need be to somewhere far from any celestial objects (in fact this is never zero), so it wouldn't be practical. The 'apparent weight' is defined as the normal force N, which is the interaction force between your feet and the floor. This force can be zero (or almost zero in the case of the pool) in the situations described in a previous post. It is in connection with the 'apparent weight' that the term 'weightlessness' is defined and used.

 

[AshUchiha]

In Physics books they are talking about 'real weight' and 'apparent weight'. The real weight is mg, so for this to be zero you would need be to somewhere far from any celestial objects (in fact this is never zero), so it wouldn't be practical. The 'apparent weight' is defined as the normal force N, which is the interaction force between your feet and the floor. This force can be zero (or almost zero in the case of the pool) in the situations described in a previous post. It is in connection with the 'apparent weight' that the term 'weightlessness' is defined and used.

Oh my god! I've been studying Weight as the summation of Mass and gravity, and not Mass times gravity!.I'm soo sorry virgil .
Tell me this, would I feel acceleration due to gravity if I put my feet above from ground for like, say 1/2 second. The accel. due to gravity is 9.8m/s^2. So its for 1 second right?. So what about when my feet is half second to upward to reach the ground?. Would it be the half of 9.8m/s^2

 

[phinds]

Oh my god! I've been studying Weight as the summation of Mass and gravity, and not Mass times gravity!.I'm soo sorry virgil .
Tell me this, would I feel acceleration due to gravity if I put my feet above from ground for like, say 1/2 second. The accel. due to gravity is 9.8m/s^2. So its for 1 second right?. So what about when my feet is half second to upward to reach the ground?. Would it be the half of 9.8m/s^2

When you jump up such that your body is completely off the ground, you are weightless until you touch down again. You are being acted on by gravity but you have no weight, exactly as though you were in orbit. This is what I was trying to get you to understand earlier.

 

[AshUchiha]

True , thanks sir. Though the velocity we will fall would be different due to the different mass . And what about my accel. due to gravity question??

 

[Nugatory]

Though the velocity we will fall would be different due to the different mass

No. The velocity of a falling object is independent of the mass. This is a FAQ up in the "STEM Learning Materials" section of this forum.

This thread has drifted far from its original topic, and there is little point in continuing the random walk approach to learning physics. Instead, I suggest that you work on acquiring a clear sense of what is meant by "mass", "weight", "speed", "velocity", "force", and "acceleration" and the mathematical relationships between them. Until you've built this foundation (which we can help you with) you will find it very difficult to make sense of anything here.