Additional Info

• ID Code: H6-04
• Purpose: Demonstrate the rise in frequency of vocal formants due to the increase in the speed of sound in a light gas.
• Description: Inhale a small quantity of helium and talk and sing normally. Your voice takes on a squeaky "Donald Duck" character due to the increase in frequency of your vocal formants.

  This demonstration has the potential to be dangerous if misused, and must only be used after instruction by Lecture-Demonstration personnel. The purpose of this demonstration is to illustrate the effect of vocal formants, not as entertainment for groups where the physics content is not discussed. Take a couple of big breaths of air first to get plenty of oxygen, then breath out completely before inhaling the helium. Videos of this effect may be more useful in many classes.

• Availability: Available
• References: REFERENCES: (PIRA 3B30.50)
• Loc codes: H6, FS1