RPM said:
That's just it. There are not exactly the same.
The scales compress and the dummy blocks stay the same height.
Old diet scales with springs in them compressed... like crazy.
They'd compress 1/2".
Because that type of scale is actually measuring how much
a spring travels, to give you a number.
Digital scales don't work that way, they work on load cells,
and compress very, very, little..
The amount they compress would yield an error factor of
probably less than the tolerance of the scale.
I understand your arguments, completely, and they have merit.
but they are the classic example, of over teching ourselves.
Because the variations are so small that measuring them, especailly
in percentages is nearly impossible.
You simply cannot get the accuracy needed to make these calculations,
using 2 dollar Chinese scales..
To explain where I'm coming from,
just out of curiosity, I set up one of my digital scales on a
surface plate. I then took a dial indicator, and fixture, and positioned
it on the scale platform, and preloaded the scale to 100g.
Zeroed out the dial indicator, and added 200g.
The scale platform compressed .0035"....
35/10,000 of an inch....
Which is about .001" less than the thickness of a piece of heavy paper.
This difference, when viewed relative to a solid block,
is absolutely negligible.
Especially given the equipment, a non-laboratory grade scale
that only reads in 1/10th gram increments and has a
plus/minus accuracy of maybe 2%.........