When sound waves hit an object, they cause that object to move. Those movements are so tiny that we usually can't see them, let alone understand them as information. But researchers at MIT developed a means to translate those vibrations into sound.
As a demonstration, they pointed a camera through a window at a bag of potato chips. Then, perhaps as a reference to the earliest sound recordings, they played Mary Had a Little Lamb. The camera recorded the movement of the bag. A computer program analyzed that footage and reconstructed a clear performance of the song.
In fact, the reconstructions that the team made were so clear that they were understandable by a song recognition app. It's amazing! And also kind of scary.
-via Twisted Sifter