Q: If two people talk in a room having Helium gas higher than usual, will they hear any change in the pitch of sound?

A: Yes, if two people talk in a room with helium gas, the pitch of their voices will change. Helium is much less dense than air, which means that sound travels faster through it. Considering resonance vibration of vocal chord, the resonance frequency is proportional to the speed of sound. As a result, the pitch of the sound waves produced by the vocal cords will be higher, making the voices sound like they have a higher pitch or a cartoon-like quality. This effect is known as the “helium voice” or the “Mickey Mouse effect.”

It’s worth noting that the amount of helium needed to produce this effect is relatively small. Even a small increase in the concentration of helium in the air can produce noticeable changes in the pitch of sound. However, it’s important to be cautious when working with helium, as it can be dangerous if not handled properly.