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Why Isaac Newton Believed Stupid Things
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James McGinn
Apr 4, 2016, 5:33:03 AM4/4/16
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https://solvingtornadoesdotcom.wordpress.com/2015/06/03/why-scientists-believe-stupid-things/
Why Scientists Believe Stupid Things
My response to:
http://usatoday30.usatoday.com/weather/wdensity.htm
USA Today:
Most people who haven't studied physics or chemistry find it hard to believe
that humid air is lighter, or less dense, than dry air. How can the air become
lighter if we add water vapor to it?
James McGinn:
This is a myth. Humid air is heavier, not lighter, than dry air. Only people
that don't understand science believe moist air is lighter than dry air.
USA Today:
Scientists have known this for a long time.
James McGinn:
Actually this is false. Or, I should say, it would be more accurate to say
that scientists have ASSUMED this for a long time. Something can't be known
unless is is measured, tested, or observed. That is not the case with this myth
that moist air is lighter than dry air.
USA Today:
The first was Isaac Newton, who stated that humid air is less dense than dry
air in 1717 in his book, Optics. But, other scientists didn't generally
understand this until later in that century.
James McGinn:
Was this guy Isaac Newton a saint? Was he visiting us from the future? Or was
he a human being, capable of making a mistake? I think the latter is the case.
And I think the fact that he stated something doesn't make it known. Again, for
it to be known it would have to be measured, tested, or observed.
USA Today:
To see why humid air is less dense than dry air, we need to turn to one of the
laws of nature the Italian physicist Amadeo Avogadro discovered in the early
1800s. In simple terms, he found that a fixed volume of gas, say one cubic
meter, at the same temperature and pressure, would always have the same number
of molecules no matter what gas is in the container.
James McGinn:
This is true. There is just one problem. H2O is not a gas at ambient
temperatures/pressures. It is still liquid. It consists of microdroplets of
liquid H2O suspended by electro-static forces between air molecules. Often
these microdroplets are very small, so small they are invisible--just as
invisible as gaseous H2O (this is what confuses most of us). All in all, there
is zero evidence that moisture in our atmosphere is mono-molecular (gaseous)
and there is a wealth of laboratory evidence that confirms that gaseous H2O can
only exist above it's boiling point.
USA Today:
Most beginning chemistry books explain how this works. Imagine a cubic foot of
perfectly dry air. It contains about 78% nitrogen molecules, which each have a
molecular weight of 28 (2 atoms with atomic weight 14) . Another 21% of the air
is oxygen, with each molecule having a molecular weight of 32 (2 stoms with
atomic weight 16). The final one percent is a mixture of other gases, which we
won't worry about. Molecules are free to move in and out of our cubic foot of
air.
James McGinn:
Up to this point everything they are saying here is accurate. Here is where
the problem lies:
USA Today:
What Avogadro discovered leads us to conclude that if we added water vapor
molecules to our cubic foot of air, some of the nitrogen and oxygen molecules
would leave -- remember, the total number of molecules in our cubic foot of air
stays the same. The water molecules, which replace nitrogen or oxygen, have a
molecular weight of 18. (One oxygen atom with atomic weight of 16, and two
hydrogen atoms each with atomic weight of 1). This is lighter than both
nitrogen and oxygen. In other words, replacing nitrogen and oxygen with water
vapor decreases the weight of the air in the cubic foot; that is, it's density
decreases.
James McGinn:
The real number that should be used here is not 18. It is 18 x X, X being the
number of H2O molecules in the microdroplet. What is the correct number for X?
Well, the truth is we don't know. It is, in my opinion, most likely never
smaller than 10, thus the correct number to put into this equation wouldn't be
18 it would be 180 or larger. It is possible it might be as small as 3 in some
particularly dry bodies of air, in which case it would be 54, still making
moist air considerably heavier than dry air. But even if it is only 2 it will
make moist air, at 36, heavier than dry air.
So, if somebody tells you that the notion that moist air is heavier than dry
air is a myth you can tell them that this myth is actually a myth. You can
also tell them that Isaac Newton was not a deity sent from heaven but a normal
human being, prone to the foibles of confirmation bias, just like the rest of
us.
Why Scientists Believe Stupid Things
My response to:
http://usatoday30.usatoday.com/weather/wdensity.htm
USA Today:
Most people who haven't studied physics or chemistry find it hard to believe
that humid air is lighter, or less dense, than dry air. How can the air become
lighter if we add water vapor to it?
James McGinn:
This is a myth. Humid air is heavier, not lighter, than dry air. Only people
that don't understand science believe moist air is lighter than dry air.
USA Today:
Scientists have known this for a long time.
James McGinn:
Actually this is false. Or, I should say, it would be more accurate to say
that scientists have ASSUMED this for a long time. Something can't be known
unless is is measured, tested, or observed. That is not the case with this myth
that moist air is lighter than dry air.
USA Today:
The first was Isaac Newton, who stated that humid air is less dense than dry
air in 1717 in his book, Optics. But, other scientists didn't generally
understand this until later in that century.
James McGinn:
Was this guy Isaac Newton a saint? Was he visiting us from the future? Or was
he a human being, capable of making a mistake? I think the latter is the case.
And I think the fact that he stated something doesn't make it known. Again, for
it to be known it would have to be measured, tested, or observed.
USA Today:
To see why humid air is less dense than dry air, we need to turn to one of the
laws of nature the Italian physicist Amadeo Avogadro discovered in the early
1800s. In simple terms, he found that a fixed volume of gas, say one cubic
meter, at the same temperature and pressure, would always have the same number
of molecules no matter what gas is in the container.
James McGinn:
This is true. There is just one problem. H2O is not a gas at ambient
temperatures/pressures. It is still liquid. It consists of microdroplets of
liquid H2O suspended by electro-static forces between air molecules. Often
these microdroplets are very small, so small they are invisible--just as
invisible as gaseous H2O (this is what confuses most of us). All in all, there
is zero evidence that moisture in our atmosphere is mono-molecular (gaseous)
and there is a wealth of laboratory evidence that confirms that gaseous H2O can
only exist above it's boiling point.
USA Today:
Most beginning chemistry books explain how this works. Imagine a cubic foot of
perfectly dry air. It contains about 78% nitrogen molecules, which each have a
molecular weight of 28 (2 atoms with atomic weight 14) . Another 21% of the air
is oxygen, with each molecule having a molecular weight of 32 (2 stoms with
atomic weight 16). The final one percent is a mixture of other gases, which we
won't worry about. Molecules are free to move in and out of our cubic foot of
air.
James McGinn:
Up to this point everything they are saying here is accurate. Here is where
the problem lies:
USA Today:
What Avogadro discovered leads us to conclude that if we added water vapor
molecules to our cubic foot of air, some of the nitrogen and oxygen molecules
would leave -- remember, the total number of molecules in our cubic foot of air
stays the same. The water molecules, which replace nitrogen or oxygen, have a
molecular weight of 18. (One oxygen atom with atomic weight of 16, and two
hydrogen atoms each with atomic weight of 1). This is lighter than both
nitrogen and oxygen. In other words, replacing nitrogen and oxygen with water
vapor decreases the weight of the air in the cubic foot; that is, it's density
decreases.
James McGinn:
The real number that should be used here is not 18. It is 18 x X, X being the
number of H2O molecules in the microdroplet. What is the correct number for X?
Well, the truth is we don't know. It is, in my opinion, most likely never
smaller than 10, thus the correct number to put into this equation wouldn't be
18 it would be 180 or larger. It is possible it might be as small as 3 in some
particularly dry bodies of air, in which case it would be 54, still making
moist air considerably heavier than dry air. But even if it is only 2 it will
make moist air, at 36, heavier than dry air.
So, if somebody tells you that the notion that moist air is heavier than dry
air is a myth you can tell them that this myth is actually a myth. You can
also tell them that Isaac Newton was not a deity sent from heaven but a normal
human being, prone to the foibles of confirmation bias, just like the rest of
us.
noTthaTguY
Apr 5, 2016, 2:32:37 PM4/5/16
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this is quite cloe to the problem of Snell's laW,
which eLFig screwed-up, totally, saying that
light goes faster in denser media
which eLFig screwed-up, totally, saying that
light goes faster in denser media
noTthaTguY
Apr 6, 2016, 11:09:08 AM4/6/16
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sound waves faster in a denser medium,
in water than in air e.g;
all of whch is really cOOl
in water than in air e.g;
all of whch is really cOOl
James McGinn
May 25, 2016, 9:46:45 PM5/25/16
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James McGinn
Aug 14, 2016, 4:04:07 PM8/14/16
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On Monday, April 4, 2016 at 2:33:03 AM UTC-7, James McGinn wrote:
Solving Tornadoes
Mar 25, 2017, 11:13:06 PM3/25/17
to
On Monday, April 4, 2016 at 2:33:03 AM UTC-7, James McGinn wrote:
Solving Tornadoes
Apr 10, 2017, 11:02:29 PM4/10/17
to
On Monday, April 4, 2016 at 2:33:03 AM UTC-7, James McGinn wrote:
James McGinn
Jun 5, 2017, 11:52:21 AM6/5/17
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On Monday, April 4, 2016 at 2:33:03 AM UTC-7, James McGinn wrote:
James McGinn
Aug 28, 2017, 2:31:02 PM8/28/17
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On Monday, April 4, 2016 at 2:33:03 AM UTC-7, James McGinn wrote:
James McGinn
Mar 12, 2018, 5:10:45 PM3/12/18
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James McGinn
Apr 27, 2018, 4:40:08 PM4/27/18
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On Monday, April 4, 2016 at 2:33:03 AM UTC-7, James McGinn wrote:
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