Author Topic: Heavy Air  (Read 8301 times)

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Offline Sanguine

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Re: Heavy Air
« Reply #25 on: August 10, 2019, 12:32:10 am »
@DeerSlayer - I'm the mod for this thread.  Is there a point to it?

Offline ChemEngrMBA

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Re: Heavy Air
« Reply #26 on: August 10, 2019, 08:22:37 pm »
@DeerSlayer - I'm the mod for this thread.  Is there a point to it?

How surprising that you have to ask.  It begins with the challenge - what is the mass of a cubic mile of air. This is to see if anyone here has the education background to answer the relatively simple question.  Nobody did. 

The second point is how profoundly surprising the answer is - it amazes even commercial pilots, and I have challenged many of them with this question.  Five million tons of air in one cubic mile.
And you had to ask why I posed such a question?
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Offline bigheadfred

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Re: Heavy Air
« Reply #27 on: August 10, 2019, 09:11:38 pm »
Soooo....

Is this one of those "sucking all the oxygen from the room" moments?
She asked me name my foe then. I said the need within some men to fight and kill their brothers without thought of Love or God. Ken Hensley

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Re: Heavy Air
« Reply #28 on: August 10, 2019, 09:35:12 pm »
Soooo....

Is this one of those "sucking all the oxygen from the room" moments?

Fred Just Breathe, breathe in the air
Run, rabbit run
Dig that hole, forget the sun
And when at last the work is done
Don't sit down, it's time to dig another one
For long you live and high you fly
But only if you ride the tide
And balanced on the biggest wave
You race towards an early grave
I am just a Technicolor Dream Cat riding this kaleidoscope of life.

Offline Sanguine

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Re: Heavy Air
« Reply #29 on: August 10, 2019, 10:01:23 pm »
How surprising that you have to ask.  It begins with the challenge - what is the mass of a cubic mile of air. This is to see if anyone here has the education background to answer the relatively simple question.  Nobody did. 

The second point is how profoundly surprising the answer is - it amazes even commercial pilots, and I have challenged many of them with this question.  Five million tons of air in one cubic mile.
And you had to ask why I posed such a question?

Yeah, I though so.   :laugh:

Offline Bigun

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Re: Heavy Air
« Reply #30 on: August 10, 2019, 10:07:44 pm »
@DeerSlayer

Just so you know, there are plenty of people here with the ability to answer the question but, it seems, no one thought it worth the effort.
"I wish it need not have happened in my time," said Frodo.

"So do I," said Gandalf, "and so do all who live to see such times. But that is not for them to decide. All we have to decide is what to do with the time that is given us."
- J. R. R. Tolkien

Offline corbe

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Re: Heavy Air
« Reply #31 on: August 10, 2019, 10:09:44 pm »
   I'm a bit confused, apparently this seems to require a bit of mathematics and I'm stoned so yall are all a bunch of racist.
No government in the 12,000 years of modern mankind history has led its people into anything but the history books with a simple lesson, don't let this happen to you.

Offline DB

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Re: Heavy Air
« Reply #32 on: August 10, 2019, 10:35:29 pm »
How surprising that you have to ask.  It begins with the challenge - what is the mass of a cubic mile of air. This is to see if anyone here has the education background to answer the relatively simple question.  Nobody did. 

The second point is how profoundly surprising the answer is - it amazes even commercial pilots, and I have challenged many of them with this question.  Five million tons of air in one cubic mile.
And you had to ask why I posed such a question?

Air pressure at sea level is 14.70 psi @ 15C. Air pressure at an elevation of 5,280 feet (one mile) is 12.10 psi @ 15C. The difference is 2.6 psi. There are 4,014,489,600 square inches in a square mile. Therefore a cubic mile of air starting at sea level weighs 2.6 x 4,014,489,600 = 10,437,672,960 lbs or 5,218,836.48 US tons.

Offline corbe

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Re: Heavy Air
« Reply #33 on: August 10, 2019, 10:49:35 pm »
    I still don't understand @DB (thanks for trying) so here's some Marianne Williamson with her song

Elvis Costello & The Attractions - (What's So Funny 'Bout) Peace, Love And Understanding


Error 404 (Not Found)!!1

No government in the 12,000 years of modern mankind history has led its people into anything but the history books with a simple lesson, don't let this happen to you.

Offline Elderberry

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Re: Heavy Air
« Reply #34 on: August 10, 2019, 10:53:28 pm »
Don't forget to factor in the humidity of the air. The more humid the air is the less dense it is. After all where are you going to find a cubic mile of dry air to fill the box?

Offline ChemEngrMBA

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Re: Heavy Air
« Reply #35 on: August 11, 2019, 05:54:42 pm »
Don't forget to factor in the humidity of the air. The more humid the air is the less dense it is. After all where are you going to find a cubic mile of dry air to fill the box?

@DB showed how simple it really was to do.  His answer was 5,218,836.48 tons.
This is nine significant figures, using STP (standard temperature and pressure, viz. zero degrees celsius and 760 Torr, or 14.7 PSI at sea level). The whole point was to demonstrate how ENORMOUS is the weight of air.  Many people guess "nothing.  Air is weightless," they say. 
If that were the case, aircraft could not fly.  Nobody ever guesses a weight as huge as five million tons.

The humidity of air is highly dependent on the temperature.   At twenty-five degrees Celsius, the difference in density between dry air and saturated air is on the order of 1 or 2 percent.  It's lost in the long line of numbers of tons.

https://www.engineeringtoolbox.com/density-air-d_680.html

There is no need to "find" dry air.  It's all a mind exercise.  No such box will ever exist, much less a scale with which to weigh it.



« Last Edit: August 11, 2019, 09:15:26 pm by DeerSlayer »
The Book Commentary: "The book (Brilliant Creations - The Wonder of Nature and Life) is pure genius."
Review by John Orosz, M.D. "It is beyond outstanding. Please send me twenty signed copies for colleagues, family, and libraries."
"I was running every morning for twenty years with a genius." - Mike McCartney, D.D.S.
"You have the most agile mind of anyone I know." -
Avice Marie Griffin, PhD, Clinical Psychologist

Offline ChemEngrMBA

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Re: Heavy Air
« Reply #36 on: August 11, 2019, 05:58:37 pm »
Soooo....

Is this one of those "sucking all the oxygen from the room" moments?

Only if you don't enjoy using the brain God gave you, and expects you to use.
The Book Commentary: "The book (Brilliant Creations - The Wonder of Nature and Life) is pure genius."
Review by John Orosz, M.D. "It is beyond outstanding. Please send me twenty signed copies for colleagues, family, and libraries."
"I was running every morning for twenty years with a genius." - Mike McCartney, D.D.S.
"You have the most agile mind of anyone I know." -
Avice Marie Griffin, PhD, Clinical Psychologist

Offline Bigun

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Re: Heavy Air
« Reply #37 on: August 11, 2019, 06:03:27 pm »
@DB showed how simple it really was to do.  His answer was 5,218,836.48 tons.
This is nine significant figures, using average figures. The whole point was to demonstrate how ENORMOUS is the weight of air.  Many people guess "nothing.  Air is weightless," they say. 
If that were the case, aircraft could not fly.  Nobody ever guesses a weight as huge as five million tons.

The humidity of air is highly dependent on the temperature.   At twenty-five degrees Celsius, the difference in density between dry air and saturated air is on the order of 1 or 2 percent.  It's lost in the long line of numbers of tons.

https://www.engineeringtoolbox.com/density-air-d_680.html

There is no need to "find" dry air.  It's all a mind exercise.  No such box will ever exist, much less a scale with which to weigh it.

I suppose I would have gotten the wrong answer because I would simply have determined the number of cubic feet in a cubic mile and divided by 379 which results in a number very much larger than 5 million.

1 pound mole of any gas equals 379 scf.
« Last Edit: August 11, 2019, 06:05:14 pm by Bigun »
"I wish it need not have happened in my time," said Frodo.

"So do I," said Gandalf, "and so do all who live to see such times. But that is not for them to decide. All we have to decide is what to do with the time that is given us."
- J. R. R. Tolkien

Offline ChemEngrMBA

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Re: Heavy Air
« Reply #38 on: August 11, 2019, 09:28:34 pm »
I suppose I would have gotten the wrong answer because I would simply have determined the number of cubic feet in a cubic mile and divided by 379 which results in a number very much larger than 5 million.

1 pound mole of any gas equals 379 scf.

I have never seen the figure 379 scf before you presented it.  The reason your method would overstate the weight is that it implicitly assumes standard pressure, which is only the case very close to sea level.    Of course it diminishes considerably at elevation.

Pilots learn an interesting aspect of elevation, by the way. It is called the "lapse rate" and is ~3 degrees F per thousand feet.  On a flying vacation with my family, it was 100 degrees over the deserts of Arizona and Utah, but I few at 10,000 feet where it was a cool 70 degrees.  I dropped  down into the Grand Canyon which is huge enough to do figure eights in.  My radio speaker went quiet beneath the rim as radio waves travel line of sight.
The Book Commentary: "The book (Brilliant Creations - The Wonder of Nature and Life) is pure genius."
Review by John Orosz, M.D. "It is beyond outstanding. Please send me twenty signed copies for colleagues, family, and libraries."
"I was running every morning for twenty years with a genius." - Mike McCartney, D.D.S.
"You have the most agile mind of anyone I know." -
Avice Marie Griffin, PhD, Clinical Psychologist

Offline Bigun

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Re: Heavy Air
« Reply #39 on: August 12, 2019, 01:36:35 am »
I have never seen the figure 379 scf before you presented it.  The reason your method would overstate the weight is that it implicitly assumes standard pressure, which is only the case very close to sea level.    Of course it diminishes considerably at elevation.

Pilots learn an interesting aspect of elevation, by the way. It is called the "lapse rate" and is ~3 degrees F per thousand feet.  On a flying vacation with my family, it was 100 degrees over the deserts of Arizona and Utah, but I few at 10,000 feet where it was a cool 70 degrees.  I dropped  down into the Grand Canyon which is huge enough to do figure eights in.  My radio speaker went quiet beneath the rim as radio waves travel line of sight.

I think I have discovered our problem @DeerSlayer.  Your question was "what is the mass..."  and I took that to mean weight when you were talking about the density.  But then why was your answer given in pounds?   :shrug:
"I wish it need not have happened in my time," said Frodo.

"So do I," said Gandalf, "and so do all who live to see such times. But that is not for them to decide. All we have to decide is what to do with the time that is given us."
- J. R. R. Tolkien

Offline Elderberry

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Re: Heavy Air
« Reply #40 on: August 12, 2019, 02:07:37 am »
Slugs, not pounds, are used for mass in the US Customary Measurement System. Anyhow for the results to be mass, one would need to divide the weight by 32.1740.

Offline Bigun

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Re: Heavy Air
« Reply #41 on: August 12, 2019, 02:22:20 am »
1 cubic foot of air at standard temperature and pressure assuming average composition weighs approximately 0.0807 lbs.
"I wish it need not have happened in my time," said Frodo.

"So do I," said Gandalf, "and so do all who live to see such times. But that is not for them to decide. All we have to decide is what to do with the time that is given us."
- J. R. R. Tolkien

Offline Elderberry

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Re: Heavy Air
« Reply #42 on: August 12, 2019, 02:26:56 am »
But he asked for mass not weight.

Offline Bigun

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Re: Heavy Air
« Reply #43 on: August 12, 2019, 02:35:47 am »
But he asked for mass not weight.

Yes.  They are not unrelated
"I wish it need not have happened in my time," said Frodo.

"So do I," said Gandalf, "and so do all who live to see such times. But that is not for them to decide. All we have to decide is what to do with the time that is given us."
- J. R. R. Tolkien

Offline corbe

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Re: Heavy Air
« Reply #44 on: August 12, 2019, 02:40:40 am »
    TTIUWP:



                    Explain the mass of a woman on air?
No government in the 12,000 years of modern mankind history has led its people into anything but the history books with a simple lesson, don't let this happen to you.

Offline Elderberry

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Re: Heavy Air
« Reply #45 on: August 12, 2019, 02:42:05 am »
  I agree. Related most definitely.


Offline Sanguine

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Re: Heavy Air
« Reply #46 on: August 12, 2019, 02:43:30 am »
Y'all keep that up and I'm bringing out the men in kilts.

Offline Bigun

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Re: Heavy Air
« Reply #47 on: August 12, 2019, 02:51:10 am »
As is the norm for me, I wish to hell I had read through the entire thread before I  chimed in.
"I wish it need not have happened in my time," said Frodo.

"So do I," said Gandalf, "and so do all who live to see such times. But that is not for them to decide. All we have to decide is what to do with the time that is given us."
- J. R. R. Tolkien

Offline corbe

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Re: Heavy Air
« Reply #48 on: August 12, 2019, 03:01:54 am »
    @Bigun it also took me almost 7 years to get through it.
     I still think there's a conspiracy. 
No government in the 12,000 years of modern mankind history has led its people into anything but the history books with a simple lesson, don't let this happen to you.

Offline Bigun

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Re: Heavy Air
« Reply #49 on: August 12, 2019, 03:12:15 am »
    @Bigun it also took me almost 7 years to get through it.
     I still think there's a conspiracy.

I blame it on late Sunday evening boredom @corbe.
"I wish it need not have happened in my time," said Frodo.

"So do I," said Gandalf, "and so do all who live to see such times. But that is not for them to decide. All we have to decide is what to do with the time that is given us."
- J. R. R. Tolkien