What is sound? Really? Chances are you’ve never thought about it much. Your ears hear it and that’s good enough for you. Music, voices, thunder, raindrops- all these have their own sound or sounds. But sound is merely vibrations in the air that our ears pick up and resonate as “sound” to our brains.
And vibrations, we now know, are everywhere, all around us, all the time. Everything that is or ever was is vibrating to some degree. It’s noticeable when it comes from an erupting volcano, or an earthquake under our feet. Less noticeable if it’s the statue of David or the book stand in the corner of your living room. But all these things are vibrating-all the time. And if sound is only vibration waves at a frequency our ears can register- then what sound does your bookshelf make?
It was questions like this that led Abe Davis and his team to develop an algorithm that could take silent video of such objects and turn them into sound, or even voices. If this intrigues you, I suggest you watch the video below; but basically it works like this:
Abe takes a bag of potato chips, and with several lamps he illuminates the bag so that any vibration on a micro pixel level would be picked up by their high speed camera. He then recites Mary Had a Little Lamb– loudly toward the bag. They then take this video, and through their algorithm, take what was a silent video and replay the sound that caused microscopic vibration waves on the bag of chips. In this case, Mary Had a Little Lamb.
We’re just discovering what applications this technology can have, but the final segment of Abe’s talk shows just how powerful this imaging technique can be. It’s truly amazing.