Tuning fork shatters teeth/explodes eyeball?

[FrogFeathers]

The parts below in "quotes" are the words my 15 year old son used when he told me this on the way to school.

Jason's 9th grade science teacher told them that if they "get a tuning fork going" and touch it to their teeth, it would shatter their teeth- or if they touch their eyeball, it would cause the eyeball to explode.

He went on to say it was "pure energy" and that your teeth are safe if you touch your chin, because "it has cushioning" of the skin and fatty tissue.

I was just wondering if this is true or just something teachers tell kids to keep them from playing with the tuning forks in class. I honestly cannot remember hearing this in science class when we worked with tuning forks.

I said to Jason: "Hmmm, this sounds UL-ish, I'll ask the snopsters and find out."

Thanks.

[Stoneage Dinosaur]

Whether or not it has ever actually happened, it looks as if teachers in the UK have also been told to tell their pupils this - Sound lesson notes.

Note

Tuning forks should not be banged on the desk, nor should they come into contact with the teeth, because teeth have been known to shatter

You have a chunk of metal vibrating at a high rate. Sort of like a mini jackhammer. Now the amount of energy is not that much (how hard did you hit it to begin with?), but it is energy that will result in metal tapping a tooth. So I would guess that a good tooth would be fine, but one that has "issues" might chip.

The eye is jelly, it won't explode (but poking it with a tuning fork or other hard object will hurt).

Note that my Dad had a tooth that crumbled when the dentist checked it out. The cavity was so big, there was not much tooth left, so I bet that had they touched that tooth of my Dad's with a tuning fork, it would have shattered. Maybe that's where it comes from.

No idea about the eyeball exploding thing...

[Tarquin Farquart]

In my science lessons when I was at school, there were people who'd try and make their eyeballs explode if they were told that.

[Troberg]

Nope, didn't work, although the teeth felt a bit wierd. I didn't put it directly on the eye (for fear of scratching), just the eyelid.

[inkrose115]

Well the eye can be scratched by a sharp edge, and you don't even know it. And it can be enough that the virtious fluid leaks out slowly. Now, let's say that right after that, you apply vibrating metal to that. I imagine it would be quite disturbing to have a bit of fluid leak out from your eye.

[jimmy101_again]

Total BS. A generic tuning fork won't hurt an eyeball or a tooth. At least, not any worse than touching either with a hunk of metal.

Besides, given the "safety paranoia" in most schools' science classes what are the chances that there would be any object that could actually hurt a person like that?

[Floater]

If true, wouldn't a jew's harp be even more dangerous to your teeth?

[Silas Sparkhammer]

Originally Posted by jimmy101_again

Total BS. A generic tuning fork won't hurt an eyeball or a tooth. At least, not any worse than touching either with a hunk of metal.

But, as Doug4.7 points out, it's a moving piece of metal, carrying a significant amount of energy (depending, as he notes, upon how hard you banged it on the table in the first place.) Suppose I strike it with the equivalent force of dropping it from two meters. That's a fair hunk of energy! Sure, the conversion of energy results in a loss of energy -- it isn't quite as bad as dropping the fork from two meters directly onto one of your teeth! -- and I agree that it would be unlikely to shatter a tooth. But it seems to me that there is enough energy here to chip the surface enamel.

Silas

[FrogFeathers]

Thanks much!

You all basically confirmed what I thought.

[Ali Infree]

If true, wouldn't a jew's harp be even more dangerous to your teeth?

I don't know about more dangerous, but it does hurt if you don't follow the instructions.
Still never saw anyone's tooth explode, and eyeball playing never came up, even during psychedelic episodes.

Ali "music to my ears" Infree

[Hans Off]

I think the implication is that the fork will make your teeth/eyeballs resonate and "shatter" (like the opera singer wine glass trick)

In which case it's a load of crap because your eyes would burst and teeth would explode if you went to a load concert.

(although it does sometimes feel like that if the band is shoddy enough)

[Don Enrico]

Originally Posted by Silas Sparkhammer

But, as Doug4.7 points out, it's a moving piece of metal, carrying a significant amount of energy (depending, as he notes, upon how hard you banged it on the table in the first place.) Suppose I strike it with the equivalent force of dropping it from two meters. That's a fair hunk of energy! Sure, the conversion of energy results in a loss of energy -- it isn't quite as bad as dropping the fork from two meters directly onto one of your teeth! -- and I agree that it would be unlikely to shatter a tooth. But it seems to me that there is enough energy here to chip the surface enamel.

Silas

Wouldn't the tuning fork - not being made for that kind of impact - just bend or break, thereby taking up most of the energy?

Don Enrico

[Eddylizard]

I thought the implication (re teeth at least) is not the fork resonating in harmony with the teeth.

If you use a tuning fork properly, strike it and hold it on a table, then you get the sound of the tuning fork amplified by the table.

But if you hold the tuning fork too loosly, it just rattles and buzzes on the table, bouncing up and down (minutely) such that, depending on the surface table top, you can end up with a small dent in the surface.

I can see this happening with a loosly held fork, and a tooth. Whether the tooth would shattter completely I doubt. There would be some damage though.

I don't see this happening with an eyeball. Even if you could bear to try it, the more elastic nature of the eyeball would probably dampen the movement of the fork.

[Silas Sparkhammer]

Originally Posted by Don Enrico

Wouldn't the tuning fork - not being made for that kind of impact - just bend or break, thereby taking up most of the energy?

Well, remember that it's made to take the impact of being smacked against a table to get it humming... These puppies are made of hardened metal; if they were susceptible to bending, then the sonic energy would quickly be lost to bending and waste heat.

I do know that if you hold the tines of a tuning fork to a table top, you can get a lovely "buzzing" noise. I don't have one any longer, but I would wager that you could cause small scars on a wooden table this way.

If so, then maybe you could damage the surface enamel of a tooth, or even cause a tiny nick in the cornea of an eye.

To utterly shatter a tooth or an eye might be possible, if you had an utterly ginormous sonic weapon, as seen in the Tintin book The Calculus Affair or in Ayn Rand's Atlas Shrugged. Such weapons have been experimented with, but are extremely wasteful of energy, and easily defended against.

Silas

[ganzfeld]

I'm going to say yes for teeth. They are hard and brittle and have a specific resonant frequency. They can break if hit with a tuning fork. Anyone who has ever learned to play jaw harp has come close to chipping or cracking a tooth, not from the moving metal part but just from the vibration. As the jaw harp shows, that would be rare but a tuning fork vibrates a lot more than the solid part of a jaw harp. I would put one on my teeth. Ouch. (The vibrating lip of the harp, on the other hand, can easily crack a tooth, not from resonance but simply from the movement. A tuning fork probably could do damage that way, too.)

I say no for eyes. The eye is made up of several structures, each with a different resonant frequency. I don't think it would break from an ordinary tuning fork any more than a balloon would. Too unlikely.

[Hans Off]

Originally Posted by ganzfeld

I'm going to say yes for teeth. They are hard and brittle and have a specific resonant frequency. .

Which is?

I think it's a load of doo-doo.

Do dentists use sonic drills or am I mis-remembering? If they do then the frequencies used are well out of the tonal range that you would produce with a tuning fork.

[Hero_Mike]

Wouldn't the effectiveness of a tuning fork on shattering a tooth have to do with its frequency?

That is to say, what is the resonant frequency of a human tooth?

If the tuning fork is at the resonant frequency, then yes, it would be likely to shatter. But not if it was significantly more or less. A dentist's drill is probably tuned to be at the right frequency, as it is intended to drill out only the material it touches, rather than causing the whole tooth (or even neighbouring teeth in contact with the one being drilled) to shatter.

[Silas Sparkhammer]

Originally Posted by Hans Off

I think it's a load of doo-doo.

Well, there's the title of a formal paper ready for for submission to the New England Journal of Medicine...

Do dentists use sonic drills or am I mis-remembering? If they do then the frequencies used are well out of the tonal range that you would produce with a tuning fork.

Ultrasonic; as you note, far beyond the resonant frequencies of our teeth. A fair amount of energy, but only able to affect very, very small areas. Good for bouncing plaque off enamel. (I do not know what would happen if one were misused: can an ultrasonic dental periodontic cleaner or scaler do damage to the enamel if applied directly to it?)

Silas

[Corwin]

Originally Posted by Floater

If true, wouldn't a jew's harp be even more dangerous to your teeth?

I chipped my front tooth with a jew's harp once.