ABSTRACT
This chapter examines the parameters that cause error in mass determinations. Subjects covered are mass artifacts, mass standards, mass comparison, the fundamental mass relationship, weighing designs, uncertainties in the determination of the mass of an object, buoyancy, thermal equilibrium, atmospheric effects, cleaning of mass artifacts, magnetic effects, and instability of the International Prototype Kilogram. The gravitational force exerted on a balance mechanism by a standard kilogram is compared to the gravitational force exerted by an artifact of mass and density nominally equal to those of the standard kilogram to determine the mass of the artifact. The mass of mass standards, after specified cleaning, is affected by variation in atmospheric variables in an otherwise clean environment. In ultrahigh-accuracy mass determination, it is necessary to minimize the magnetic interaction between magnetic structures and the mass artifacts being compared. The Bureau International des Poids et Mesures cleaning and washing procedures for platinum-iridium mass standard artifacts involves solvent cleaning and steam washing.
