WEBVTT - BrainStuff Classics: Is There A Noise Loud Enough To Kill You?

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<v Speaker 1>Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff,

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<v Speaker 1>I'm Lauren Vogelbaum, and today's episode is another classic from

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<v Speaker 1>our former host, Christian Sagar. Our question of the day

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<v Speaker 1>is a little morbid and hopefully not pressing to anyone listening,

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<v Speaker 1>but interesting. Nonetheless, if a noise was loud enough, could

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<v Speaker 1>it straight up kill you? Hey, I'm Christian Sagar, and

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<v Speaker 1>this is brain Stuff. If you're standing next to a

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<v Speaker 1>jet during takeoff, your ear drums will probably burst. Same

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<v Speaker 1>thing happens when you fire a twelve gage shotgun right

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<v Speaker 1>next to your ear. When we're exposed to exceptionally loud noises,

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<v Speaker 1>something called the stereo cilia in our ears gets damaged.

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<v Speaker 1>This causes our ears to mistakenly send signals to our

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<v Speaker 1>auditory nerve cells. The resulting ghostly reverberations are what we

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<v Speaker 1>call ringing ear. Many of you have probably experienced this,

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<v Speaker 1>possibly for going to a really loud concert. The technical

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<v Speaker 1>term for it is tenitis, and it's usually temporary unless

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<v Speaker 1>you repeatedly damage your ears with loud noises. Then it

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<v Speaker 1>develops into chronic tenitis, where you hear that dull ringing

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<v Speaker 1>for the rest of your life and that's nothing compared

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<v Speaker 1>to what really loud noise can do to you. Noise

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<v Speaker 1>hates you, and noise can kill you. See, sound travels

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<v Speaker 1>in waves that enter our ear canals. These waves make

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<v Speaker 1>our ear drums vibrate, and if they're too strong, they

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<v Speaker 1>can snap the hair cells inside, and if these hair

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<v Speaker 1>cells die, they can never grow back. To avoid this,

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<v Speaker 1>we use units called decibels to measure the power of sound.

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<v Speaker 1>Anything below eighty five decibels is thought to be safe.

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<v Speaker 1>At a hundred and fifty decibels, your ear drums burst

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<v Speaker 1>like with the jet or the shotgun, and at two

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<v Speaker 1>hundred decibels, your lungs will rupture and likely kill you.

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<v Speaker 1>That's right. The threshold for death by sound is somewhere

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<v Speaker 1>between a hundred and eighty five and two hundred decibels.

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<v Speaker 1>What happens is the sound causes an air embolism within

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<v Speaker 1>your lungs that can travel to your heart and kill

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<v Speaker 1>you dead. That is, if your lungs don't burst first

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<v Speaker 1>from the increased air pressure caused by acoustic energy. This

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<v Speaker 1>has happened during wars when high energy impulse noise from

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<v Speaker 1>explosions causes something called blast over pressure. It leaves no

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<v Speaker 1>external injuries, but damages organs like your ears, lungs, and

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<v Speaker 1>gastro intestinal tract. Now, acoustic weapons are actually being developed,

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<v Speaker 1>but usually there for non lethal purposes. There's been talk

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<v Speaker 1>of acoustic bullets to burst ear drums, incapacitate a target,

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<v Speaker 1>or even kill them. Others claim that an infrasound generator

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<v Speaker 1>could also be lethal, but there's been little practical evidence

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<v Speaker 1>of such weapons so far. The closest we've seen is

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<v Speaker 1>a long range acoustic hailing device developed by the l

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<v Speaker 1>RAD co Operation, which can cause hearing damage from up

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<v Speaker 1>to fifty feet or fifteen point two four meters away.

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<v Speaker 1>Some shipping companies have started using these devices as seaborn

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<v Speaker 1>defense against pirates. There is one device, however, that could

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<v Speaker 1>most definitely kill you with sound. It's not a weapon,

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<v Speaker 1>but the European Space Agency has developed a huge air

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<v Speaker 1>horn that they used to test satellites and spacecraft, using

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<v Speaker 1>nitrogen gas to produce sounds up to one hundred and

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<v Speaker 1>fifty four decibels. They blast objects to make sure they

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<v Speaker 1>can withstand the noise of a rocket launching. The e

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<v Speaker 1>s A themselves are so concerned about how lethal this

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<v Speaker 1>horn is they've surrounded it with half meter thick walls

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<v Speaker 1>made of steel reinforced concrete coated with an epoxy resin

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<v Speaker 1>to reflect noise back into its chamber. But Christian, you're asking,

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<v Speaker 1>didn't you just say that the threshold for death is

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<v Speaker 1>between one hundred and eighty five and two hundred decibels.

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<v Speaker 1>It's true, I did, But the e s A believe

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<v Speaker 1>that prolonged exposure to the one and fifty four decibel

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<v Speaker 1>horn will kill you as well, probably rupturing your ear drums,

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<v Speaker 1>vibrating your eyeballs, and destroying you from the inside out.

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<v Speaker 1>If you're not dead, you'll probably wish you were. Today's

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<v Speaker 1>episode was written by Christian and produced by Tyler Klang.

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<v Speaker 1>If you miss Mr Sager, check out his pop culture

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<v Speaker 1>podcast super Context, available wherever you get your podcasts, and

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<v Speaker 1>of course, for more on this and lots of other topics,

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<v Speaker 1>visit our home planet, astu works dot com.