Ear drum and the hydrogen atom

[Wavicle]

Hi Everyone,

I have several times come across the claim (on creationist sites) that the ear drum (or maybe the lever action of the bones connected to it) can detect sounds that move the membrane just 1/10 the diameter of a hydrogen atom (I think that works out to about 10 picometers). A quick google search turns up non creationist sites that say the same thing.

Maybe it is true, but intuitively it just feels to me like that amount of movement is so small that just the random collisions of air molecules against the ear drum would move it at least that far, if not an order of magnitude more. If nothing else, the blood moving around the ear would move it more than that with every heart pump - or at least it intuitively seems like it would.

Could someone fill in where my intuition is failing here? The scale here seems so small that it is hard to imagine a mechanical device that reliably functions at that accuracy.

[sophia8]

Could someone fill in where my intuition is failing here? The scale here seems so small that it is hard to imagine a mechanical device that reliably functions at that accuracy.
There is such a device. (http://cat.inist.fr/?aModele=afficheN&cpsidt=18472156)Here, we present results from a laser Doppler vibrometer that we designed to noninvasively probe cochlear mechanics near auditory threshold. This device enables picometer-sized vibration measurements of the human eardrum in vivo. With this sensitivity, we found the eardrum frequency response to be linear down to at least a 20-dB sound pressure level (SPL). Nonlinear cochlear amplification was evaluated with the cubic distortion product of the otoacoustic emissions (DPOAEs) in response to sound stimulation with two tones. DPOAEs originate from mechanical nonlinearity in the cochlea. For stimulus frequencies, fi and f2, with f2/f1= 1.2 and f2 = 4-9.5 kHz, and intensities Li and L2, with L1= 0.4L2 + 39 dB and L2 = 20-65 dB SPL, the DPOAE displacement amplitudes were no more than 8 pm across subjects (n = 20), with hearing loss up to 16 dB. DPOAE vibration was nonlinearly dependent on vibration at f2. T
That may be where the claim comes from. Though why this should be proof of ID, I have no idea.

ETA: A bit more googling throws up the information that a hydrogen atom is probably around 50PM, but
Size loses a little meaning on these scales, as the wave nature of matter begins to noticably manifest itself.

[Dancing David]

Hello,

My guess is that they are leaving out some crucial stuff, the sites i saw had no reference to why they make that claim.

My guess and it is solely a guess is that they are talking about the difference in 'motion' in a distinguisable pitch frequency shoft. Like the difference between two wavelengths of pressure waves (sound) or something like that. So my guess is that they have taken a snippet out of the context in which it is placed. And made it into something it is not.

[Ivor the Engineer]

IIRC, the picometre-sized movement refers to the motion of the stereocilia on the hair cells in the cochlea.

ETA: Site with some nice pictures: http://www.bcm.edu/oto/research/cochlea/Hearing/

[Wowbagger]

It was evolutionary biologists who first emprically tested the sensativity of the ear drum. Anyone can say what they want about the validity of Evolution. But, at least the theory helps us develop more and more precise knowledge about life forms.

What new, precise, knowledge have Creationists ever generated?

[Wavicle]

There is such a device. (http://cat.inist.fr/?aModele=afficheN&cpsidt=18472156)
That may be where the claim comes from. Though why this should be proof of ID, I have no idea.

ETA: A bit more googling throws up the information that a hydrogen atom is probably around 50PM, but

My 10pM size came from a website that suggested the distance from proton to electron (radius) was 48pM, so I estimated diameter would be 100pM and 1/10 that to be 10pM. If the real answer is 5pM I'll accept that as well. The quote you had drives at my trouble with this measurement:

Size loses a little meaning on these scales, as the wave nature of matter begins to noticably manifest itself.

Exactly. I don't have much formal education in particle physics (despite the name I use on the board) but it just feels like at that scale quantum mechanics might have something to say about your ability to detect that movement.

Also, whether it is the cilia in the cochlea or the ear drum or whatever - if they are in a fluid medium, intuitively it seems like the random interactions between the molecules in the fluid and your detector would create a noise floor that is at least an order of magnitude larger than what is being measured.

Again, I realize my intuition might be off. I'm just trying to get a grasp on where this comes from.

[Wavicle]

It was evolutionary biologists who first emprically tested the sensativity of the ear drum. Anyone can say what they want about the validity of Evolution. But, at least the theory helps us develop more and more precise knowledge about life forms.

What new, precise, knowledge have Creationists ever generated?

My hope wasn't to start a CrEvo debate, I do that too much as it is :)

This is just a claim of theirs that I'm incredulous about but haven't found much response.

[Dancing David]

Again I am not sure what it is that the measurement is based upon, I agree that the base motion of fluid molecules in the fluid in the inner ear would seem larger than that.

However if you were to measure the difference in wave length of two pitch frequencies that are just discernable as seperate that might be the difference in the two wave lengths.

[jj]

Hi Everyone,

I have several times come across the claim (on creationist sites) that the ear drum (or maybe the lever action of the bones connected to it) can detect sounds that move the membrane just 1/10 the diameter of a hydrogen atom (I think that works out to about 10 picometers). A quick google search turns up non creationist sites that say the same thing.

Maybe it is true, but intuitively it just feels to me like that amount of movement is so small that just the random collisions of air molecules against the ear drum would move it at least that far, if not an order of magnitude more. If nothing else, the blood moving around the ear would move it more than that with every heart pump - or at least it intuitively seems like it would.

Could someone fill in where my intuition is failing here? The scale here seems so small that it is hard to imagine a mechanical device that reliably functions at that accuracy.

Well, the threshold of hearing (meaning what you can just barely hear in an otherwise quiet setting) is very near the level at which the atmosphere creates random noise at the eardrum due to the molecular nature of air.

Zero dB SPL is approximately 10^(-19.2/2) atmospheres. (Using the psychoacoustical value, not the mechanical value for 0dB SPL, which is always relative to some reference.)

In terms of that zero db SPL, the 20Hz to 20kHz white noise due to the atmosphere's discrete nature is about 6dB SPL.

Since that's a broadband number, the fact that this works out near -15dB SPL give or take at the ear canal resonance puts the noise level due to pure thermal sources of noise in the atmosphere very nearly at audibility. Hard to test, of course, because that requires removing the air from both sides of the eardrum, which tends to annoy subjects, to say the least.

I should know the displacement value, but don't recall it offand.

[Wowbagger]

My hope wasn't to start a CrEvo debate, I do that too much as it is :)

This is just a claim of theirs that I'm incredulous about but haven't found much response.
Yeah, I understand. Sorry if I came off sounding all hard-nosed and such. But, that type of thing seems to be developing into my default, knee-jerk, response to such claims. Perhaps this is a habit I should try to get out of.

[Wowbagger]

By the way, here are some responses: http://www.talkorigins.org/indexcc/CB/CB302.html

[RecoveringYuppy]

However if you were to measure the difference in wave length of two pitch frequencies that are just discernable as seperate that might be the difference in the two wave lengths.
Don't think so. Even at 20K HZ sound waves have wavelengths nearly an inch long. And a single HZ difference results in 33 micro-inch difference.

[Dancing David]

But how does that translate into the oscilation of the eardrum and through the middle ear to the cochlea, I would assume the motion may get smaller. I will have to search for some sources.

ETA
Here they are the last one is rather intense and i will have to read it in the morning, I can understand it but I am too tired to read anymore.

So basically the motion of the eardrum can be very small , but remember it is not a single motion which creates the sound it is the repeated movement of vibration which creates the sound. The last article seems to say a lot about it, the eardrum's vibrations are transmitted to the cochlea where some really cool stuff happens. So while the motion of atoms and molecules may produce movement in the mechanism it will not produce consistent vibration.

I would assume the the window of the cochlea amplifies the whole thing (sorry it has been 22 since I got my BS in psych.)

http://www.tufts.edu/as/wright_center/workshops/workshop_archives/physics_2003_wkshp/book/chapter_1.pdf

At this smallest of perceptible sound intensities, the eardrum vibrates less distance than the diameter of a hydrogen atom! Well, it's so small an amount of power that you can hardly conceive of it, but if you have pretty good hearing, you could detect a sound wave with that small amount of power.

http://www.yale.edu/ynhti/curriculum/units/2000/5/00.05.10.x.html

The ear is the organ in humans which perceives sound. Reasonable acoustics is somewhat subjective; it depends on individual and cultural norms and standards which are not necessarily permanent but acceptable for the age, time and setting. Sound is actually the result of “an organized disturbance of pressure in the air. The human ear is capable of perceiving sounds which are so weak that they cause the ear drum to displace by less than the size of a hydrogen atom which has a diameter of about a billionth of an inch. Such a faint sound has a pressure disturbance of about a billionth of one atmospheric pressure (which is about 14.7 pounds per square inch or 0.1 MPa). Extremely loud sounds which normally produce pain, have sound pressures of about one thousandth of an atmosphere.



http://bmb.oxfordjournals.org/cgi/content/full/63/1/223

[Dancing David]

Now you may question why an article about the sounds (IE pressure waves) generated by the cochlea leads anywhere!

But here is the paragraph snippets from the section ‘How do OAE arise’> The cochlea as stimulus delivery system


Even healthy ears have a slight ‘conductive loss’ because not all of the available sound energy enters the cochlea. The proportion which does enter the cochlea depends on how efficiently the middle ear mechanism couples the low acoustic impedance of air to the high mechanical impedance of the fluid-filled cochlea. The round window plays an important role in releasing cochlear fluid pressure caused by stapes displacement thereby greatly reducing the cochlear input impedance. This increases cochlear fluid motion which eventually excites the inner hair cells (Fig. 4). In contrast, acoustic pressure in the cochlear perilymph is almost instantly transmitted to every cell, but causes no sound sensation.
[/quote}

>The need for a cochlear amplifier (Explains why there is a mechanism to compensate for the loss of energy in fluid damping and absorption by the mechanism)

[quote]
It is not that cochlear fluids become any ‘thicker’ or more viscous than water in the deaf or dead cochlea. These viscous losses are physically inevitable because: (i) sensory cells must absorb stimulus energy to operate; and (ii) in order to reach the inner hair cells, cochlear fluid motion must take place in the extremely constricted sub-tectorial space (Fig. 4B). The energy lost from the TW due to viscous fluid drag in the subtectorial space plus energy absorbed by the hair cell themselves is very substantial. In fact the majority of the incident stimulus energy is actually lost before reaching its appropriate frequency place. Under purely mechanical forces, the cochlea cannot develop a strong and sharp TW image.
The mammalian cochlea has evolved a unique mechanism for replacing TW energy lost by viscosity, at least for weak stimuli. The idea of a ‘cochlear amplifier’ to overcome physical limitations was first proposed by Gold19. It was revived following the discovery of OAEs3,20, but became a credible possibility only after the discovery of hair cell motility by Brownell21. Electro-motility (Ashmore, this volume) is the only known functional characteristic of the outer hair cells, which out-number the inner hair cells by 3:1 (Fig. 4A).


So now for a new source on cochlear amplification!

[Dancing David]

States the gain from cochlear amplification is ~60db

From 2002 article

http://apl.sphs.indiana.edu/papers/Withnell_et%20al_2002_eh.pdf

Theoretical mechanism : Positive feed back process


The first step in the amplification process is the
displacement of the basilar membrane produced by
stapes vibration-induced volume displacement of
fluids in the cochlea. This volume displacement
produces a pressure gradient across the basilar
membrane. Deformation of the basilar membrane
produces a shearing action between the tectorial
membrane and the reticular lamina, producing a
deflection of the stereocilia of the receptor cells. Both
inner and outer hair cells have fine (tip) links that
mechanically join adjacent stereocilia. Deflection of
the stereocilia is thought to produce a force on the
transduction channels via these links, opening the
channels§ (Pickles, Comis, & Osborne, 1984). Potassium
ions flow through open transduction channels_
raising the intracellular potential and altering the
potential difference across the basolateral wall,
which in the inner hair cells (IHCs) results in a
release of neurotransmitter at afferent synapses
(see Fig. 5).



Deflection of the stereocilia modulates this standing
current so that current flow is increased when
stereocilia are deflected away from the modiolus
(excitatory direction), and current flow is decreased
when stereocilia are deflected towards the modiolus
(inhibitory direction).



Extended discussion of potential mechanism for OHC (outer hair cells) to cause a translation of the variation in the electrical ion differential into mechanical amplification. Possible mechanisms discussed.


There is a lot of research after this 2002 article to determine how the OHC actualy drive the BM (basliar membrane) , my brain will overload if I try to scan and understand any more.

So it would appear there something really cool in mammalian cochlea, just as there is something even cooler in some eyeballs (like crabs) and all organs.

[ddt]

There is a lot of research after this 2002 article to determine how the OHC actualy drive the BM (basliar membrane) , my brain will overload if I try to scan and understand any more.

So it would appear there something really cool in mammalian cochlea, just as there is something even cooler in some eyeballs (like crabs) and all organs.
Last week, I attended a lecture by an audiologist on the working of the (inner) ear. He explained the working of inner and outer hair cells as follows.

The inner hair cells only trigger the hearing nerve when they touch the "ceiling" of the organ of Corti. In order to make this happen, the OHC make for an amplification mechanism: as soon as they pick up vibratoins, they send a signal to the brain and the brain sends a signal back, ordering the OHC to go vibrate. The vibrations of the OHC make the whole organ vibrate and thus the IHC to touch the ceiling and thus have the hearing nerve transmit a signal to the brain that a sound is heard.

[Complexity]

I'm sure the cretins are trying for "Only god could make something so marvelous!"

Idiots.

[Wowbagger]

I'm sure the cretins are trying for "Only god could make something so marvelous!"

Idiots.
Yeah, and if it's so marvelous, why is it so piss-poor?

I don't think it would have taken God much more effort to create micro-hairs that can grow back after being damaged. Instead, He chose to plague us with the danger of permanent hearing loss?! "Intelligent" my foot!

[Ivor the Engineer]

Yeah, and if it's so marvelous, why is it so piss-poor?

I don't think it would have taken God much more effort to create micro-hairs that can grow back after being damaged. Instead, He chose to plague us with the danger of permanent hearing loss?! "Intelligent" my foot!

What happens to your intelligently designed PC if a single transistor fails in the CPU? We each loose millions of neurons per day and don't even notice.

Intelligence in design often shows up as very limited tolerance to fault conditions.

[Wowbagger]

What happens to your intelligently designed PC if a single transistor fails in the CPU? Transistors don't grow themselves in CPUs. (at least not with current technology)

Hair does grow on various parts of the body, and sometimes continues to grow throughout one's life. Why can't the micro-hairs in ears do the same?

We each loose millions of neurons per day and don't even notice.Not on a day-to-day basis, at any rate. If you suddenly experienced 10 years worth of neuron loss in one minute, you probably would notice.

[Dancing David]

Last week, I attended a lecture by an audiologist on the working of the (inner) ear. He explained the working of inner and outer hair cells as follows.

The inner hair cells only trigger the hearing nerve when they touch the "ceiling" of the organ of Corti. In order to make this happen, the OHC make for an amplification mechanism: as soon as they pick up vibratoins, they send a signal to the brain and the brain sends a signal back, ordering the OHC to go vibrate. The vibrations of the OHC make the whole organ vibrate and thus the IHC to touch the ceiling and thus have the hearing nerve transmit a signal to the brain that a sound is heard.


Thanks!

[Ivor the Engineer]

Transistors don't grow themselves in CPUs. (at least not with current technology)

Not yet, but we're getting there:

http://www.technologyreview.com/Nanotech/20368/

Correction to my previous post: We loose roughly 100,000 neurons per day, not millions as I stated previously.

(Apparently I lost the ones required to store that particular piece of information correctly.)