Sensitivity of touch can be down to a few nanometres according to a study done in 2013
I can feel dirt on a mirror or on a porcelain basin, most people could I suspect,
Human touch extends down to the nano-level
How sensitive are the other senses?
sight
taste
smell
hearing range from 20 to 20,000 Hz, but what about how soft a noise is heard at, in db level?
CrazyNeutrino said:
sight
I can see waves of light down to 400 nanometres
CrazyNeutrino said:
Sensitivity of touch can be down to a few nanometres according to a study done in 2013
I can feel dirt on a mirror or on a porcelain basin, most people could I suspect,
Human touch extends down to the nano-level
How sensitive are the other senses?
sight
taste
smell
hearing range from 20 to 20,000 Hz, but what about how soft a noise is heard at, in db level?
I found some information on hearing here
http://hyperphysics.phy-astr.gsu.edu/hbase/sound/earsens.html
It is capable of detecting pressure variations of less than one billionth of atmospheric pressure. The threshold of hearing corresponds to air vibrations on the order of a tenth of an atomic diameter. This incredible sensitivity is enhanced by an effective amplification of the sound signal by the outer and middle ear structures. Contributing to the wide dynamic range of human hearing are protective mechanisms that reduce the ear’s response to very loud sounds. Sound intensities over this wide range are usually expressed in decibels.
dv said:
CrazyNeutrino said:sight
I can see waves of light down to 400 nanometres
Violet (380-450 nm) very small
CrazyNeutrino said:
hearing range from 20 to 20,000 Hz, but what about how soft a noise is heard at, in db level?
Hearing is interesting. Ohm, who first established the range of frequencies the ear is sensitive to, did some experiments to determine whether it’s sensitive to the sound’s phase; he concluded it’s not. Some experiments* I’ve done suggest that it’s sensitive to gross phase changes, but not to shorter changes. As to the sensitivity of the eardrum to pressure changes, it can detect a half bee’s wing dropped from 1cm onto it. The accepted standard pressure limits for the ears are about 20 μPa to about 17kPa (which can rupture the eardrum).
* One experiment: take 100 seconds of speech, fft it, extract the frequency and phase components, randomise the phase, inverse fft the result, and listen to the result. If the fft is done over the whole 100 seconds, the result is unintelligible; if the 100 seconds is broken into short (about 10ms) segments, then the above performed on each segment, the result is easily intelligible.
btm said:
* One experiment: take 100 seconds of speech, fft it, extract the frequency and phase components, randomise the phase, inverse fft the result, and listen to the result. If the fft is done over the whole 100 seconds, the result is unintelligible; if the 100 seconds is broken into short (about 10ms) segments, then the above performed on each segment, the result is easily intelligible.
Err, that doesn’t surprise me in the slightest.
sibeen said:
btm said:* One experiment: take 100 seconds of speech, fft it, extract the frequency and phase components, randomise the phase, inverse fft the result, and listen to the result. If the fft is done over the whole 100 seconds, the result is unintelligible; if the 100 seconds is broken into short (about 10ms) segments, then the above performed on each segment, the result is easily intelligible.
Err, that doesn’t surprise me in the slightest.
seems obv
perception’s probably a bit more complex than each in the title indicates, + often involve composites of senses
Great link to research on touch, CN.
Somewhere, I have the book “Supersense”, based on the TV series of the same name. That series looks into the senses (in six episodes) of animals compared to those of humans.
https://en.wikipedia.org/wiki/Supersense
I’m on record as saying that some people can see six colours rather than the usual three:
The normal red, green, blue, a shifted red in one eye seen my tetrachromats, a grey-blue from rod cells in the retina, and a blue-violet normally blocked by the cornea seen by people who have had cataract operations.
Being red-green colourblind I can only see up to about 670 nm rather than the usual 700 nm.
Sensitivity to sound is not limited to the human ear. Infrasound is detectable as vibration and ultrasound (if intense enough) as tickling.
I was sceptical about the touch down to the nano-level thing, but it seems that it is something we just take for granted. Running my finger over the “smooth” area of my laptop keyboard, not only do the Intel and AMD stickers feel like huge mountains, the model name which seems to be printed on is clearly detectable to touch, although looking absolutely flat to close visual inspection.
I wonder what the evolutionary advantage of this sensitivity was. More accurate spear throwing perhaps?
The Rev Dodgson said:
I was sceptical about the touch down to the nano-level thing, but it seems that it is something we just take for granted. Running my finger over the “smooth” area of my laptop keyboard, not only do the Intel and AMD stickers feel like huge mountains, the model name which seems to be printed on is clearly detectable to touch, although looking absolutely flat to close visual inspection.I wonder what the evolutionary advantage of this sensitivity was. More accurate spear throwing perhaps?
Perhaps a labourers cracked and calloused hands don’t have the sensitivity of a modern day desk jockey like you and me Rev.
>I wonder what the evolutionary advantage of this sensitivity was. More accurate spear throwing perhaps?
itchies, mate, bugs crawlin’ on ya. A sheep can (for example) can sense a fly walking on two inches of wool, which has advantages re avoiding fly strike(maggots)
anyway there’re probably many reasons, how cool does evaporation feel?
or ya lady breathin’ on the back of ya neck, mate, i’m gettin’ erection i’d better stop.
had a little thought after I closed the browser, re fingers, digits, appendages. Given like fingers do a broad range of work, much heavier (rough too) work, there’s protective advantages in having them sensitive because it inclines aversion to damaging them/pain. And they’re high-value tools that’re often (potentially) in harms way
much of the skin over the entire body is highly sensitive, and no less so where there is hair, as a fly(for example) walking on my arm hairs is very noticable, possibly more sensitive than if walking on skin.
The Rev Dodgson said:
I was sceptical about the touch down to the nano-level thing, but it seems that it is something we just take for granted. Running my finger over the “smooth” area of my laptop keyboard, not only do the Intel and AMD stickers feel like huge mountains, the model name which seems to be printed on is clearly detectable to touch, although looking absolutely flat to close visual inspection.I wonder what the evolutionary advantage of this sensitivity was. More accurate spear throwing perhaps?
hands are kind of important… if they were less sensitive I’d say it would be more likely they would suffer injury rates as a result of accidents.
diddly-squat said:
The Rev Dodgson said:
I was sceptical about the touch down to the nano-level thing, but it seems that it is something we just take for granted. Running my finger over the “smooth” area of my laptop keyboard, not only do the Intel and AMD stickers feel like huge mountains, the model name which seems to be printed on is clearly detectable to touch, although looking absolutely flat to close visual inspection.I wonder what the evolutionary advantage of this sensitivity was. More accurate spear throwing perhaps?
hands are kind of important… if they were less sensitive I’d say it would be more likely they would suffer injury rates as a result of accidents.
The degree of sensitivity of our hands are I think, far more important than just having the ability to detect pain. Our hands are highly dexterous and being so sensitive would encourage investigation of objects from which texture can play an important part of our understanding. Besides enabling a possible use, or a reason for avoidance, greater sensitivity would also enable more sophisticated tool manufacture and use. Therefore the evolutionary advantage of highly sensitive hands would enhance our understanding and generally improve our intelligence level.