Speaker 1: Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff,
Speaker 1: I'm Lauren Vogelbaum, and today's episode is another classic from
Speaker 1: our former host, Christian Sagar. Our question of the day
Speaker 1: is a little morbid and hopefully not pressing to anyone listening,
Speaker 1: but interesting. Nonetheless, if a noise was loud enough, could
Speaker 1: it straight up kill you? Hey, I'm Christian Sagar, and
Speaker 1: this is brain Stuff. If you're standing next to a
Speaker 1: jet during takeoff, your ear drums will probably burst. Same
Speaker 1: thing happens when you fire a twelve gage shotgun right
Speaker 1: next to your ear. When we're exposed to exceptionally loud noises,
Speaker 1: something called the stereo cilia in our ears gets damaged.
Speaker 1: This causes our ears to mistakenly send signals to our
Speaker 1: auditory nerve cells. The resulting ghostly reverberations are what we
Speaker 1: call ringing ear. Many of you have probably experienced this,
Speaker 1: possibly for going to a really loud concert. The technical
Speaker 1: term for it is tenitis, and it's usually temporary unless
Speaker 1: you repeatedly damage your ears with loud noises. Then it
Speaker 1: develops into chronic tenitis, where you hear that dull ringing
Speaker 1: for the rest of your life and that's nothing compared
Speaker 1: to what really loud noise can do to you. Noise
Speaker 1: hates you, and noise can kill you. See, sound travels
Speaker 1: in waves that enter our ear canals. These waves make
Speaker 1: our ear drums vibrate, and if they're too strong, they
Speaker 1: can snap the hair cells inside, and if these hair
Speaker 1: cells die, they can never grow back. To avoid this,
Speaker 1: we use units called decibels to measure the power of sound.
Speaker 1: Anything below eighty five decibels is thought to be safe.
Speaker 1: At a hundred and fifty decibels, your ear drums burst
Speaker 1: like with the jet or the shotgun, and at two
Speaker 1: hundred decibels, your lungs will rupture and likely kill you.
Speaker 1: That's right. The threshold for death by sound is somewhere
Speaker 1: between a hundred and eighty five and two hundred decibels.
Speaker 1: What happens is the sound causes an air embolism within
Speaker 1: your lungs that can travel to your heart and kill
Speaker 1: you dead. That is, if your lungs don't burst first
Speaker 1: from the increased air pressure caused by acoustic energy. This
Speaker 1: has happened during wars when high energy impulse noise from
Speaker 1: explosions causes something called blast over pressure. It leaves no
Speaker 1: external injuries, but damages organs like your ears, lungs, and
Speaker 1: gastro intestinal tract. Now, acoustic weapons are actually being developed,
Speaker 1: but usually there for non lethal purposes. There's been talk
Speaker 1: of acoustic bullets to burst ear drums, incapacitate a target,
Speaker 1: or even kill them. Others claim that an infrasound generator
Speaker 1: could also be lethal, but there's been little practical evidence
Speaker 1: of such weapons so far. The closest we've seen is
Speaker 1: a long range acoustic hailing device developed by the l
Speaker 1: RAD co Operation, which can cause hearing damage from up
Speaker 1: to fifty feet or fifteen point two four meters away.
Speaker 1: Some shipping companies have started using these devices as seaborn
Speaker 1: defense against pirates. There is one device, however, that could
Speaker 1: most definitely kill you with sound. It's not a weapon,
Speaker 1: but the European Space Agency has developed a huge air
Speaker 1: horn that they used to test satellites and spacecraft, using
Speaker 1: nitrogen gas to produce sounds up to one hundred and
Speaker 1: fifty four decibels. They blast objects to make sure they
Speaker 1: can withstand the noise of a rocket launching. The e
Speaker 1: s A themselves are so concerned about how lethal this
Speaker 1: horn is they've surrounded it with half meter thick walls
Speaker 1: made of steel reinforced concrete coated with an epoxy resin
Speaker 1: to reflect noise back into its chamber. But Christian, you're asking,
Speaker 1: didn't you just say that the threshold for death is
Speaker 1: between one hundred and eighty five and two hundred decibels.
Speaker 1: It's true, I did, But the e s A believe
Speaker 1: that prolonged exposure to the one and fifty four decibel
Speaker 1: horn will kill you as well, probably rupturing your ear drums,
Speaker 1: vibrating your eyeballs, and destroying you from the inside out.
Speaker 1: If you're not dead, you'll probably wish you were. Today's
Speaker 1: episode was written by Christian and produced by Tyler Klang.
Speaker 1: If you miss Mr Sager, check out his pop culture
Speaker 1: podcast super Context, available wherever you get your podcasts, and
Speaker 1: of course, for more on this and lots of other topics,
Speaker 1: visit our home planet, astu works dot com.