Analytical balance and the investigation of weight as a force
The balance is an instrument that allows, in a gravitational fi eld, to
measure the unknown masses by comparison with sample masses. One
sample experiment is the determination of the sensitivity of a balance
which has arms of equal length.
The more sensitive a balance is, the smaller the variation in a mass (m) the balance can detect and measure.
If the test mass (m) is lesser in magnitude than the sensitivity of the
balance, it will not be detected.
With reference to the diagram, if load a test mass (M) on each pan of
the balance and assuming that the distance between each of the pans
is equidistant and represented by “a”, we can vary weight on one of the
pans which will result in a displacement through an angle defined by α.
Therefore, we can see that the sensitivity of a balance depends on several design characteristics as well as the patience of the experimenter. For example, the more stable the design of a balance, the more mass is needed to move the balance noticeably.
Additionally, the more friction at the locations where movement is required, the less sensitive the balance will be.