Preciese measurements of physcial quantites like length, mass and time are the primary requirements fro
development fo quatitative laws of Physics or any other science.
For example in the measurement of distance of moon form earth by Laser beam, very accurate measurement
of time taken is required. Similoarly, for measuring distance, elevation and velocity of an aeroplane by Radar method, time measruement has to be accurate. For measurig distance of nearby stars, accurate
measurement of parallax angle is required.
in the field of crystallography, precise measurement of lenght is needed to determine interatomic distaances.
Using a mass spectrometer. the precision measurement of masses of atoms are made.