Rubens resonance tube

For the impressive illustration of standing waves as well as for the calculation of the speed of sound in gases;
in contrast to Kundt's tube, the differences in density in the gas are indicated by different flame heights, visible from a distance;

Robust metal tube, with 70 openings at intervals of 10 mm, for the exit of gas;
a loudspeaker is mounted at one end of the tube, a regulating valve for valve cartridges at the opposite end,
Mounting of the tube on a black bottom and back plate for high-contrast recognition of flame heights

Loudspeaker: 2 W, 8 Ohm
Dimensions (tube): D=50 mm, L=approx. 860 mm
Dimensions (total): 86x14x23 cm
Mass: 4250 g

Additionally required:
Valve cartridge
Function generator