Measuring techniques are used to confirm expected or unexpected results for physical considerations to speak in general. With the evaluation of those results, physicists or another sicentist try to understand a physical law or to prove the existence of physical phenomena.
To name a current example: gravitational-wave observatory
With such a measuring technique, the phanomena of gravitational waves were proved in the young past. This observatory consists of vacuum tubes in which the light passes through till a photodetector which measures the distance of the light. It was known that gravitational waves cause a length contraction what changes the length of the vacuum tubes (and thus the distance of the light). Thanks to improvements in such measuring techniques, scientists were able to show this length contradiction. This measuring techniques gathered such contradicitons up to 10^-22 m. With such very sensitive techniques, the existence of those waves were found out.