Debunking the Myth: Does 1 Cubic Meter of Air Really Weigh 1kg?

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Discussion Overview

The discussion revolves around the question of whether 1 cubic meter of air truly weighs 1 kilogram, exploring concepts of weight, mass, and density in different environments, including Earth and the Moon. Participants examine the implications of buoyancy and the definitions of mass and weight.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants express skepticism about the claim that 1 cubic meter of air weighs 1 kg, questioning its plausibility.
  • One participant notes that a balloon filled with air would seem weightless on Earth due to buoyancy but would exhibit weight on the Moon.
  • Another participant suggests that mass and weight have different definitions and should not be conflated.
  • A participant mentions that the weight of the air is countered by the upthrust, implying a relationship between buoyancy and perceived weight.
  • It is noted that the actual weight of 1 cubic meter of air is approximately 650 grams, which contradicts the initial claim.
  • A reference to Wikipedia is made, stating that the density of air at 15 degrees Celsius and one atmosphere is 1.29 kg per cubic meter.
  • One participant acknowledges a misunderstanding regarding the molecular composition of air, specifically nitrogen.
  • A comment is made about the difference in approach between physicists and engineers/mathematicians regarding the use of resources like Wikipedia for information.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the weight of 1 cubic meter of air, with multiple competing views and uncertainties remaining regarding the definitions of weight and mass, as well as the actual weight of air.

Contextual Notes

There are limitations in the discussion regarding the assumptions made about environmental conditions, such as temperature and pressure, which affect air density and weight. Additionally, the definitions of mass and weight are not fully explored, leaving some ambiguity.

quantum123
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Does 1 metre cube of air really weigh 1kg?
This is so hard to believe. So heavy?
 
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if it was air in a 1 metre cube balloon, it would appear to be of no/low weight on Earth because it's surrounded by air. if you bring that same balloon to the moon, you will feel the weight.

consider that mass and weight are not used the same way and have different definitions
 
well, if you bring it to an earth-sized planet with no atmostphere*
 
I get you. Thanks!
The upthrust is equal to the weight of the air itself.
 
Right. It's also not quite a kilogram. Looks to be about 650 g.
 
My bad. Nitrogen is diatomic. (Smacking forehead)
 
So physicist calculate while engineers and mathematicians look it up on the wiki...?
 

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