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Old 07-29-2019, 02:03 PM
RAMSET RAMSET is offline
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Join Date: Mar 2009
Location: NYC and Conn USA
Posts: 1,420
seems odd for a reason

The question and I suppose this is the point !

"what is the weight of a liter of water in a vacuum at sea level on Earth "

just updating here .

this question has roots in our measurement standards and "their beginnings or roots" and has relevance toward a specific observation and claim.
Apparent weight

International System of Units


This information forms the basis of what we work from, not our own personal opinion on the matter which can differ. If we do differ then we have to calmly and rationally explain why.

Pay particular attention to the following statement and try and identify what information it does not state clearly:

“The kilogram was originally defined in 1795 as the mass of a litre of water. “

Ask yourself the question... Was the kg defined as it's actual weight in 1795 or was it defined as it's apparent weight ?

I can find no reference anywhere, ever, of the measurement being done inside a vacuum chamber. Therefore I must draw the conclusion that it was not..

What this means is that if we assume that the scientists at the time were breathing air, and they were immersed in air as was the 1 litre of water and measuring scales, then they measured the apparent weight of 1 litre of water and not it's actual weight.

Therefore it follows that the weight they measured was the actual weight of 1 litre at sea level (1 atmospheric pressure) with a prime moving stress force of 1g. The actual weight of that 1 litre of water should be 1kg of water + 1 kg of air because the buoyancy force acting on that 1 litre of water is equal to the amount of air displaced by that 1 litre of water, and this must be taken into account in the measurement.

So, 1 litre of water = 1kg is the apparent weight of that mass and not the actual weight.

When I ask “what does 1 litre of water at sea level weigh in a vacuum?” I am asking you to do an apparent weight measurement.

Do not get sidetracked by “sea level”, I ask this to provide location where g = 1, and as we know the column of air that covers 1 square inch of surface area starts at sea level and stretches upward to the upper atmosphere and weighs 14.7 pounds... therefore we have a pressure at the bottom of that column that is equal to 14.7 pounds per square inch (psi).

To weigh 1 litre of water at sea level in a vacuum the mass and scales must be inside a vacuum chamber. The air pressure at sea level acts on the vacuum chamber walls and not the 1 litre of water inside the vacuum chamber. The vacuum chamber walls are strong enough to withstand 14.7psi of pressure and therefore do not collapse inward.

So atmospheric pressure is absent inside the vacuum chamber and therefore there can be no buoyancy force because the 1 litre of water is immersed in a vacuum, nothing! Therefore the measured weight at sea level is the actual weight of 1 litre of water under 1g of stress from Earth's gravity, and not the apparent weight of water, which is the actual weight minus the buoyancy force from the air that is acting upon it in opposition to gravity.

Phew... got that ?

Ok, so what does 1 litre of water weigh at sea level immersed in a container of Mercury ?
end snip
just a partial snip of the query..
more info to come

HuntingRoss ...I see your contributions here and elsewhere recently

I am grateful you take the time to analyze,critique and comment here.
this is the only way forward...brutal honesty [the scientific method}
and 100% transparency .
hopefully you will not be disappointed.

Chet K

Last edited by RAMSET; 07-29-2019 at 05:00 PM.
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