Your voice is a vibration, and you can feel it when you place a hand on your throat when you speak. As long as there are molecules around, sound will be traveling though them by smacking into each other.
What’s going on? The rubber band vibrates as you blow across the rubber band and you get a great sound. You can change the pitch by sliding the cuffs (this does take practice).
If you can’t get a sound, you may have clamped down too hard on the ends. Release some of the pressure by untwisting the rubber bands on the ends and try again. Also – this one doesn’t work well if you spit too much – wet surfaces keep the rubber band from vibrating.
