For the purpose of this thesis, it was assumed that the angular frequency of a real oscillator (a container for granular particles) depends on the density of packing of the measured polydisperse particles. In this thesis, an apparatus for the monitoring of real oscillators was made. This apparatus enables measurement of the elongation of damped oscillation of the container (with or without the sampe) from which is the angular frequency determined. The apparatus was constructed in such a manner that it allows measurement of damped oscillation about multiple parallel axes which are mutually spaced for a predetermined gap of 0.025 m. The influence of friction (between the container the the rotation axes) was maximally reduced, yet the measurements were still highly sensitive to disturbances from the surrounding like vibrations and fluctuations in the air's movement. These problems open up possibilities for further enhancements of the apparatus. The distance between a specific rotation axis and the container's central diameter and the container's central diameter moment of inertia were determined through the measurement of the container's oscillation about several parallel axes which are spaced for 0.025 m. The results were dissipated, therefore they were interpreted as the mean value. The distance between the furthest rotation axis and the container's central diameter is 0.10925 m and the container's central diameter moment of inertia is 4.35*10^-4 kgm^2. A constructed curve depicting experimentally gained data qualitatively matches the curve that was constructed from the mathematical model, but not quantitatively. Apparatus and mathematical model improvements are needed for further experiments.