Weight measurements and gravitational acceleration

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Discussion Overview

The discussion revolves around the implications of varying gravitational acceleration on weight measurements and the calibration of scales. Participants explore the distinction between mass and weight, particularly in different geographical locations, and how this affects the accuracy of measurements in practical settings.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions the calibration of scales when using weights manufactured at different locations with varying gravitational acceleration, suggesting this could lead to systematic errors.
  • Another participant clarifies that mass is typically measured using a balance, which compares two weights, and emphasizes that medical offices measure mass rather than weight.
  • There is a discussion about the terminology used, with some participants noting the distinction between weight and mass and how this is recorded in different contexts.
  • A participant asserts that scales used for commerce in the U.S. are calibrated to provide accurate mass assessments based on local conditions, implying that gravitational variations are accounted for in practice.
  • It is noted that the pound is legally defined as a unit of mass, which raises questions about the use of gravitational acceleration in weight measurements.

Areas of Agreement / Disagreement

Participants express differing views on the implications of gravitational variation for scale calibration and the distinction between mass and weight. The discussion remains unresolved regarding the extent to which gravitational acceleration affects practical measurements.

Contextual Notes

There are limitations in the discussion regarding the assumptions made about the calibration processes and the definitions of mass and weight, which may vary by context and location.

tjosan
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Hi all,

Since the gravitational acceleration varies depending on location, then how do you know if your scale is precisely calibrated? If I use a calibration weight (e.g. 100.000000 g) that was manufactured and tested around at equator where g=9.780 m/s^2, in my lab at the north pole where g=9.832 m/s^2, wouldn't I get a systematic error on my measurements?
 
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Correct. So mass is usually measured using a balance. The balance compares two weights against each other. In your doctors' office, they don't measure your weight, they measure your mass.
 
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Thank you.

Didn't distinguish between scale/balance and mass/weight. But now it makes sense :)
 
Khashishi said:
Correct. So mass is usually measured using a balance. The balance compares two weights against each other. In your doctors' office, they don't measure your weight, they measure your mass.

But they record your weight.
 
pixel said:
But they record your weight.
Only in US.
 
Khashishi said:
Only in US.

And do they use one value of g throughout the U.S.?
 
pixel said:
And do they use one value of g throughout the U.S.?
Scales (both balance and spring/load cell) used for commerce in the U.S. are calibrated to deliver an accurate assessment of the mass of the objects placed thereon in the location where they are to be used.

Just like scales everywhere else in the world.

Edit: g does not figure in. The pound is legally a unit of mass.
 

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