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