Let’s face it, Morgan Freeman has one of the BEST voices in the world: it’s deep, resonant, distinguished, and could probably narrate anything and make it tingle with gravitas. But even his unique set of tonsils aren’t immune from the wickedly mischevious effects of helium, as this fun video shows.
But how does helium do this to you? Our friends at Metafloss have neatly summarised how helium impacts on our voice, as follows:
In addition to the vibrations and manipulations that influence the sound of your voice, what another person hears when you speak also depends in part on what the space where the sound is created contains. The air that fills a room where you might be speaking to someone is made up of roughly 78.08 percent nitrogen, 20.95 percent oxygen, 0.93 percent argon, 0.038 percent carbon dioxide, and tiny amounts of other gases.
Nitrogen, which makes up the majority of our air, has a mass roughly seven times greater than that of helium. Because helium is lighter than air, sound waves travel through it faster. In a room where the temperature is 68 degrees Fahrenheit, sound travels at 344 meters a second through air, but 927 meters a second through helium.
When you inhale helium, you’re changing the type of gas molecules in your vocal tract and increasing the speed of the sound of your voice.
Some people think that helium changes the pitch of your voice, but the vibration frequency of the vocal cords doesn’t change along with the type of gas molecules that surround them. When your vocal tract is filled with helium, your vocal cords are vibrating at the same frequency as usual.
It’s actually the timbre (again, the quality of a sound that distinguishes different types of sound, also known as tone quality or tone color) that changes, because those lighter-than-air helium molecules allow sound to travel faster and change the resonances of your vocal tract by making it more responsive to high-frequency sounds and less responsive to lower ones.
Your voice winds up flat and listeners perceive this as a change in pitch.
All of which is well and good, but we’d prefer not to know the science behind it. Nah, we’d rather enjoy this video for what it is: the greatest voice in the world sounding distinctly like Donald Duck.