Time Dilation; an experiment with mu-mesons... (1960 Educational Physics).
Channel: Scarakus
Date: 2015-10-13

Using the radioactive decay of cosmic ray mu-mesons shows the dilation of time in a filmed experiment which takes place on top of Mt. Washington, N.H. and at M.I.T.in Cambridge, Mass. Explains how data are taken to determine the time distribution of the decays of mu-mesons at rest. Determines the counting rate for mu-mesons with speeds of about .99 the speed of light which arrive on top of Mt. Washington and measures the number that survive to reach sea level. Deduces from the experimental results that the mesons, moving at .99c, keep time at about 1/9th the rest rate.
Source; https://archive.org/details/TimeDilation
https://archive.org/details/academic_films