in class we recently watch a Mythbusters in which they tested whether or not a human can shatter a glass with their voice. to my surprise they were successful, this sparked my curiosity for the topic. from looking into it I found that the singer wasw able to break the glass unassisted with a combination of matching the glasses natural frequency and by using the right level of amplitude for his own. I found that by enacting these two variables onto the glass the effect would be resonance. the singer's voice would cause the glass to vibrate so much so that the glass would shatter.