how does equal arm balance compare masses accurately?

Question

Physics Scavenger Hunt

Answer 1

A balance scale measures mass.
A spring scale measures weight.
Weight depends on the force of gravity.
Mass does not depend on gravity.
There are minor variations in the force of gravity on the Earth and major variations elsewhere in the universe. These will give you different readings on a spring scale but not on a balance scale because one is actually comparing a mass against a known calibrated mass.

Answer 2

by means of the equal weights of the two arms there would be no partiality and so there is accuracybecause only the two objects weigh against each other will be considered