Editing Weighing scale (section)

====Sources of error====
Some of the sources of [[errors and residuals in statistics|error]] in weighing are:
* [[Buoyancy]] – Objects in air develop a buoyancy force that is directly proportional to the volume of air displaced. The difference in density of air due to [[barometric pressure]] and temperature creates errors.<ref>{{cite web|url=http://andrew.ucsd.edu/co2qc/handbook/sop21.pdf |title=Applying air buoyancy corrections |publisher=Andrew.ucsd.edu |date=September 29, 1997 |access-date=2014-03-05 |url-status=dead |archive-url=https://web.archive.org/web/20060907221014/http://andrew.ucsd.edu/co2qc/handbook/sop21.pdf |archive-date=September 7, 2006 }}</ref>
* Error in the mass of reference weight
* Air gusts, even small ones, which push the scale up or down
* [[Friction]] in the moving components that causes the scale to reach equilibrium at a different configuration than a frictionless equilibrium should occur.
* Settling airborne dust contributing to the weight
* Mis-calibration over time, due to drift in the circuit's accuracy, or temperature change
* Mis-aligned mechanical components due to [[thermal expansion]] or contraction of components
* [[Magnetic fields]] acting on ferrous components
* Forces from [[electrostatic field]]s, for example, from feet shuffled on carpets on a dry day
* Chemical reactivity between air and the substance being weighed (or the balance itself, in the form of [[corrosion]])
* [[Condensation]] of atmospheric water on cold items
* [[Evaporation]] of water from wet items
* [[Convection]] of air from hot or cold items
* Gravitational differences for a scale which measures force, but not for a balance.<ref>{{cite journal|url=https://www.nist.gov/calibrations/upload/nbs93-4.pdf |title=Practical Uncertainty Limits to the Mass Determination of a Piston-Gage Weight |journal=Journal of Research of the National Bureau of Standards |volume=93 |issue=4 |pages=565–571 |date=1988 |access-date=2014-02-26|doi=10.6028/jres.093.149 |last1=Davis |first1=R.S. |last2=Welch |first2=B.E. |doi-access=free }}</ref>
* Vibration and seismic disturbances