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Fingers can detect nano-scale wrinkles even on a seemingly smooth surface

sciencedaily.com

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Re: Fingers can detect nano-scale wrinkles even on a seemingly smooth surface

#41

Post by taavi013 »

Florin_Andrei wrote: post #28
ClementM wrote: post #4

The title is a bit misleading though. Though it would be real cool, saying we can detect molecule size pattern does not mean we could read Braille alphabet on molecule size dots. The eye can detect nanometer size patterns: we can make the difference between blue light ( radiation with a 400 nanometers wave length ) and red light ( radiation with a 800 nanometers wave length ). Does not mean we can see nanometer size…

It's almost certainly all about the pattern. I make telescope mirrors. The error I'm allowed is 100 nm. I would love to just drag my fingers over the glass and tell if something is not quite right with the optical surface. In reality, I need a pretty elaborate optical setup to amplify the errors about 1/2 million times, in order to see them. I'm guessing the spatial frequency of the pattern in that experiment is on t…

It is rumoured that Bernhard Schmidt had so sensitive touch, that he could physically feel polishing results by his (only) left hand.

http://en.wikipedia.org/wiki/Bernhard_Schmidt#Mittweida_year...

Re: Fingers can detect nano-scale wrinkles even on a seemingly smooth surface

#42

Post by alixaxel »

The silicon spheres for the Avogadro project were polished by a single Australian guy.

From Wikipedia (http://en.wikipedia.org/wiki/Kilogram#Avogadro_project):

These spheres are among the roundest man-made objects in the world. If the best of these spheres were scaled to the size of Earth, its high point—a continent-size area—would rise to a maximum elevation of 2.4 meters above "sea level".

^ that IS impressive ^

Re: Fingers can detect nano-scale wrinkles even on a seemingly smooth surface

#43

Post by XorNot »

weinzierl wrote: post #35
XorNot wrote: post #34

Earlier quoted context omitted.

When making nanocubes, you could still resolve that they were square even at 100 nm with an ordinary light microscope, which was a surprising (yet kind of obvious in hindsight) discovery for me. This does make me wonder if it would've been possible to feel them.

Maybe I'm missing something, but I think physics prevents this. An excellent lens has a numerical aperture of maybe 0.95 at best, so with Abbe's formula you get a resolution limit of maybe 200 nm at best. With an oil immersion microscope (still a light microscope, albeit not an ordinary one) you might get as low as 100 nm, but that doesn't mean you could see that fact that the tubes are square. It's a long time since…

No you are right - I kind of buried the lead there. The cubes themselves have a side-length of 100-120nm, but it means the longest diagonal length is actually more like ~211nm.

But there's also the 2D diagonal which is 172nm, so what seems to happen is you end up seeing two slightly super-imposed and different shaped blurs, whereas normally you'd see just the 1 if they were perfect spheres.

Re: Fingers can detect nano-scale wrinkles even on a seemingly smooth surface

#44

Post by xerophtye »

stevenrace wrote: post #9
mdm_ wrote: post #5

In the article they talk about making sections of a smartphone's screen feel different (permanently, I assume), but would it be possible to have a type of glass where the texture of the glass can be changed quickly and repeatedly by applying some sort of magnetic/electrical field and an app could, for example, make your phone's glass feel like it has buttons, then you could switch to another app and it would feel lik…

Simply put, glass is molecularly geometric - building actuated buttons into the glass itself isn't very probable. But a film of actuated buttons could be added much like with capacitive touch sensors today. Microfluidics is near the 100nm range today. Throw in a bit of ferrofluid and something like this is at least plausible. The challenge is in making all this transparent. The microfluidic channels would need to not…

If your target audience are the visually impaired, why do you need to make them transparent?

Re: Fingers can detect nano-scale wrinkles even on a seemingly smooth surface

#45

Post by Florin_Andrei »

taavi013 wrote: post #41
Florin_Andrei wrote: post #28

Earlier quoted context omitted.

It's almost certainly all about the pattern. I make telescope mirrors. The error I'm allowed is 100 nm. I would love to just drag my fingers over the glass and tell if something is not quite right with the optical surface. In reality, I need a pretty elaborate optical setup to amplify the errors about 1/2 million times, in order to see them. I'm guessing the spatial frequency of the pattern in that experiment is on t…

It is rumoured that Bernhard Schmidt had so sensitive touch, that he could physically feel polishing results by his (only) left hand. http://en.wikipedia.org/wiki/Bernhard_Schmidt#Mittweida_year...

If this is about the early stages of polishing, I believe it (and I can do it myself).
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