I read an interesting article today that explained that certain hallucinations can happen when frequencies close to that of the body affect us. For example, apparently eyes have a resonance frequency of 18 Hz, so if they are subject to frequencies similar, i might see shapes in the corner of my eyes. If my ears pick up a frequey close to their resonance frequency, I might hear strange noises, etc. But what exactly does an eye’s resonance frequency mean? I’ve heard it talked about with glass and how singing at its frequency can make it shatter, but does that mean certain sounds can make my eyes pop too?
In: 0
Humans are mushy, and sounds can press on them. Press on them at their resonant frequency, and they will vibrate. You can also shake the human to see what happens. It’s not like one frequency works for all pamts of all humans, but each part of each individual has a resonant frequency.
Enough sound energy to pop your eyes would do other harm to you.
Ok. Let’s say you have a pendulum and you go up and wack it. It’ll start moving right. But how fast it moves back and forth isn’t actually dependent on how hard you wack it. You can tap it or really hit it and it’ll move at the same rate. And that rate isn’t just some random number, it depends on the pendulum itself. This is pendulums natural frequency (or resonance frequency). Everything has a natural frequency (or multiple to be honest), including body parts but finding them can be hard.
Now instead of just hitting the pendulum, lets add a handle so we can turn it, but let’s do it in a way where it can still move on its own. Now let’s turn the handle back and forth, starting really slow. Here’s what’ll happen, the pendulum will start swinging back and forth at the rate we’re turning it. But it won’t go to far up. As we start turning it faster, the height will start going up a bit more until something interesting happens. It’ll start going really high and it’ll keep going higher and higher, even more than you’re twisting the handle. You may even be able to get to swing all the way around. What happened? You started approaching the natural frequency and then hit it. This is resonance, when you start pushing on something at the natural frequency. This can absolutely break stuff. you can shatter wine glasses and even wreck buildings (go watch the Tacoma narrows bridge collapse, wind hit a natural frequency and destroyed a bridge). It also doesn’t have to be a super simple example like we did, you can trigger this behavior indirectly as well.
If you hit the resonance frequency of the eye, you can cause weird visual effects because the eye is going to act weird. So, can you actually destroy your eye this way. Yes, yes you can. I’m not super familiar with the properties of the human body for stuff like this so I can tell you what that would take. But it would take a lot. One thing we haven’t talked about is damping. This is the ability of a material to dissipate the energy your adding with vibrations (the pendulum will eventually stop on its own in the first scenario). Some objects have a little, others have a lot. This puts a limit on the effects of resonance. You need to overcome this in order to really break things.
Eyeballs are too squishy to resonate, but they are held in a bone socket which can. This energy will cause vibrations in your eyeball, making focusing difficult. The range varies from 18 to 800Hz.
[https://www.nature.com/articles/s41598-022-08874-x](https://www.nature.com/articles/s41598-022-08874-x)
Your ear bones resonate at anything from 20Hz to 20kHz, which is the standard range of human hearing. It’s the decibels, or wave pressure, that damages hearing, not frequency.
And if your ears operate in an environment where 20 – 20kHz is available then your eyes do too, except they can’t detect such low frequencies. Our eyes are tuned to visible light, which ranges from 400THz to 790THz, where THz is a billion hertz.
Again it’s the power, not the frequency, which causes damage. Put a pig’s head in a microwave oven and its eyes will definitely pop out of its head, because the gel inside the eyeball boils and the pressure bursts the wall.
But we also live in a world full of radio, microwave and infra-red radiation, all of which hit our eyes and ears. It’s only when we go higher than visible, into UV, x-ray and gamma that the frequency, at any power, becomes dangerous.
Latest Answers