by Paffi S. Flood
Remember in science class in middle school when you learned that sound travels through vibrations in the air to your ears, and then your brain interprets them, so you can understand what you’re hearing? And the only way you couldn’t hear something was if it was in a soundproof room, where vibrations couldn’t travel out because of the soundproofing material?
Well, that appears not to be the only way a person can “hear” something.
MIT researchers found that sound can create vibrations not just in the air, but on objects. Scientists took videos of these vibrations that are invisible to the naked eye and ran them through an algorithm to isolate intelligible sound.
In one experiment, while people talked behind closed doors, testers filmed an empty potato chip bag, sitting on the other side of the room, through a soundproof window. Afterwards, they examined each minuscule movement of the bag and figured out their conversations.
In another experiment, with the mike muted on a camera, they took high-speed video of a potted plant, while music played on a speaker. Just from analyzing how the leaves wavered ever so slightly to the beat, they were able to determine the song. I imagine music from ‘80s hair bands are easier to pinpoint than ones that are accompanied only with an acoustic guitar.
So, what does this mean for writers?
Well, in a few years, a protagonist, disguised as a waiter, could serve a glass of water to a table of thieves and walk away, and still be able to determine their plans. Or she could leave aluminum foil on a suspect’s dining table and pin down his role in an investigation. How cool would that be?
As for the rest of us, that potato chip bag? To be on the safe side, make sure it’s thrown away, not in something close, like the trashcan in the kitchen, but instead in the large one in the garage.
Paffi S. Flood is the author of A Killing Strikes Home. You can also find her on twitter and facebook.