SOUND AND WAVES

RESONANCE!

Resonance is one of the most beautiful things about sound and waves.  Resonance occurs when one object's frequency matches the natural frequency of another object and causes the object to vibrate.  When they are perfectly matched, you have a perfect constructive interference and a dramatic increase in amplitude. Check out the Mythbusters as they try to shatter glass with the human voice. (You'll have to have me log in to watch this one.  Youtube took the other video down.)