Helium gas, first discovered on the Sun and named after our star named Helios, is used to fill balloons, to replace nitrogen in pressure chambers and scuba tanks, to create superconductivity, etc. In the first case, the inertness of helium and its low density are used , in the second case, helium does not create a state of intoxication among divers at depths of tens of meters, like ordinary nitrogen. In addition, at high pressures, nitrogen dissolves in the diver’s blood and, with a rapid ascent from a depth, is released from the blood in the form of bubbles that clog the vessels. There is a so-called caisson disease. And helium doesn’t behave like that.
The most important properties of helium – low density and viscosity – are the reasons for such a funny feature of this gas as an increase in the tone of voice. And in a low-density gaseous medium, consisting of oxygen and helium instead of nitrogen, the speed of sound is much greater than in ordinary air. And the volume of the oral cavity and the upper part of the throat (resonator) remains unchanged. As a result, both the frequency of vibrations of the ligaments and the frequency of the sound propagating in this resonator increase, which means the appearance of a sort of squeaky sound.
The reverse effect of lowering the frequency is possible when inhaling mixtures with inert gases heavier than nitrogen, such as inert krypton or xenon. Breathing such a mixture, an ordinary extras of the opera would have eclipsed Chaliapin himself with his bass.
However, if anyone reading these lines wants to reproduce this effect (helium is available, they inflate balloons), he must remember that with prolonged inhalation of helium-containing mixtures, oxygen starvation and loss of consciousness may occur. You need to immediately catch your breath in the fresh air.
