The buoyant force of air? Concept question

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SUMMARY

The discussion centers on the buoyant force of air and its impact on weighing objects. While buoyancy corrections are routinely applied when weighing objects in water, the negligible effect of air's buoyancy—approximately 0.1%—means it is often overlooked in everyday measurements. However, for objects with densities comparable to air, such as helium-filled balloons, this correction becomes significant. The atmospheric pressure at sea level is established at 1.013 kPa, which serves as a baseline for these measurements.

PREREQUISITES
  • Understanding of buoyancy principles
  • Knowledge of atmospheric pressure and its measurement
  • Familiarity with density concepts, particularly comparing air and water
  • Basic grasp of precision weighing techniques
NEXT STEPS
  • Research the principles of buoyancy in different fluids
  • Learn about atmospheric pressure variations and their effects on measurements
  • Explore precision weighing techniques for low-density objects
  • Investigate the properties of gases, particularly helium, in relation to buoyancy
USEFUL FOR

Students of physics, engineers involved in fluid dynamics, and professionals in fields requiring precise measurements of low-density objects will benefit from this discussion.

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if we weigh a metal object which is immersed in water, we have to correct the buoyant force for water. Air is a fluid. Why don't we correct for the buoyant force of the air when we weigh it in the air?

What i think it may be is because we have a set atmospheric pressure being 1.013 Kpa in the air and we measure everything in relation to the world relative to that?

Can someone discuss why this is, I'm not sure what i said onto is a logical quick explanation, but there should be much more to this?
 
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The density of air at sea level is about 1/800 the density of water, and the buoyancy correction for weighing most objects in air is small (less than 0.1%). The correction is applied when weighing objects very accurately.

Of course if the object being weighed has a density of the same order of magnitude as air (e.g. an inflated balloon) the correction is not negligible!
 
..especially a balloon inflated with helium.
 

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