It’s true that most scales we use are “not legal for trade”, and measure force without regard for local variations in gravitational acceleration. In order to be legal for trade, a scale must be calibrated and certified. The process of doing so involves using a known mass. A calibrated scale *does* compare the object being weighed against that mass, albeit indirectly. -- ghunchu'wI'
On Oct 29, 2020, at 11:59 AM, Will Martin <willmartin2@mac.com> wrote:
Most scales we use don’t compare two masses. They merely measure the compression of a spring or the deviation of properties of electricity passing through a physically stressed material, because that’s cheaper to make and easier to get a reading from, so we measure weight, not mass, unless we have the classic “doctor’s scale”.