This post has nothing to do with breathing the same air as Kings, Queens, or other aristocrats. It is actually about breathing the so called Noble gases, Helium, Neon, Argon, Krypton, and Xenon. This crazy experiment performed in the video below by Cody from Cody’s Lab is not without risk (even though these gases are elements that are quite unreactive), so don’t try it at home! If you want to skip ahead to the time in the video where he starts breathing the gases, it occurs at minute 4:16.
As you saw in the video, his voice went from a seemingly very high pitch after breathing the lightest gas, Helium, to a seemingly very low pitch after breathing the heaviest gas, Xenon. This is because Helium is lighter than air and the sound waves produced by the vocal chords propagate faster through it. This has the effect of amplifying the high-pitch components of the voice. With Xenon, sound waves travel slower, and this has the opposite effect. However, what is really affected by the gases is not so much the pitch of the sound but its overall quality or timbre.