Half a croissant, on a plate, with a sign in front of it saying '50c'
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Visibility through Muddy Water

See clearly in even the muddiest water
  [vote for,

The idea is to produce a localized "cloud" or channel of clean water which will displace the muddy water and create a gap between the person or camera and the subject of interest. The water supply might be hoses mounted at the side of a camera or a divers' goggles, for example.
If the water is fairly still, one only needs a slow steady supply to keep muddy water from drifting into the clean water. Use of the method in flowing water will naturally be more complicated and require more clean water. Perhaps a centrifuge and filters (on the shore or a boat) could be used to clarify muddy water fast enough to supply and maintain the visibility channel.
Another approach to this is to fill a large, clear-plastic bag with clean water and manuever it so that it is in contact with both the viewer and the subject.
Yet another approach, is to use a large, clear-plastic, pyramidal-shaped shell with a flexible plastic sheet over the larger end. This would be used just like the plastic bag, but should be more manueverable.
One could also use the pyramidal shell with an open end as a guide for the flow of clean water to reduce mixing of the muddy water with the clean.

This idea was inspired by various shows about underwater exploration on the History Channel, especially one about the "money pit".
Alvin, Nov 13 2011

GoLYTELY http://www.ncbi.nlm...dhealth/PMH0000087/
until it's watery, clear, and free of solid matter [lurch, Nov 17 2011]

The Money Pit http://en.wikipedia.org/wiki/Oak_Island
The Money Pit (on Oak Island) [Alvin, Nov 17 2011]


       You should be able to create a vortex ring of clear water and make it travel through murky water. I'm not sure how that would help but it's the only way I can think of keeping the clear water cohesive other than bagging it like you said.   

       I have been in water so cloudy I could not see the fingers on my outstretched hand and so even a bags width of viewing would help. like it the bag solution (so to speak). It would be cheap. It would not wash away. Very muddy water is also dark - but the bags could contain glowsticks or some other light.
bungston, Nov 17 2011

       I always wondered if they used something like this (injecting clear water) when conducting arthroscopic surgery. It is all well and good have miniature cameras on a flexible fibreoptic connection to look at the insides of someone's knee, but if it is full of bloody goo it would be as much use as as immersing the camera lens into a bucket of paint.
AusCan531, Nov 17 2011

       They do use injectable 'visibility mediums' for arthroscopy, but in some surgeries (such as inside the intestinal tract or abdomenal cavity), they just pump in sterilized air. My dad uses both methods regularly.
Alterother, Nov 17 2011

       //My dad uses both methods regularly//   

       Professionally or recreationally?
AusCan531, Nov 17 2011

       There was a Donald E. Westlake book (Drowned Hopes, maybe) where a diver was talking about having worked inside a sunken wreck where the water was so murky that he couldn't see. The non-diver nebbish (Dortmunder?) asked him why they hadn't just pumped clear water down into the inside of the ship's cabins.   

       The diver was left flat.   

       (Westlake later in the same book blew it by assuming that a sinking object only descends so far, then somehow goes no further.)
baconbrain, Nov 17 2011

       It should be true, the sinking object's ultimate depth. Perhaps our world's observable applications don't provide proof.
Zimmy, Nov 17 2011

       Thinking about the sinking object: why would it stop?   

       1: Object changes. The sort of change an object would undergo should make it sink more. As water pressure increases, spaces occupied by compressible gas in the object become smaller. The object becomes smaller overall, displaces less volume of water and so is less buoyant.   

       2. Difference in water. If there were a stratification - like or thermocline or especially a halocline, the sinking object might stop there. The lower layer is more dense.   

       But I bet the sinking is in analogy to floating, where the gas atmosphere does become less and less dense, and so a floating object less and less buoyant. Not true for incompressible water.
bungston, Nov 17 2011

       3. Water is somewhat compressible; an object less compressible than water could theoretically reach equilibrium.   

       4. Bottom of lake.
spidermother, Nov 17 2011

       What is less compressible than water?
bungston, Nov 17 2011

       For exploring relatively small volumes of water such as the money pit, several other methods could be used:
Heat the muddy water as much as possible to reduce its density, then add just enough baking soda and vinegar (or other gas-generating substances) to cause just enough carbon dioxide to form on the mud particles to keep them bouyant enough so that they either maintain their current depths or gradually rise to the surface (you don't want turbulence). The idea is that tiny gas bubbles will form using the mud particles as "seeds" and keep them suspended above the lower layer described below.
After that step, slowly add cold sea water or strong brine to the bottom of the pit to create a clear, dense layer.
I haven't tried calculating the expense nor other complications of this method, but it seemed too interesting to resist.
Alvin, Nov 17 2011

       //What is less compressible than water?// Diamond is about 1/200th as compressible as water, but only 3œ times as dense. Hollow diamond spheres could work.   

       "Water is incompressible" is one of those little lies that science teachers sometimes slip in to keep things simple.
spidermother, Nov 17 2011

       Exactly. Water is compressible. It could be added that "The lower compressibility of diamond means that even in the deep oceans at 4 km depth, where pressures are 40 MPa, there is only a 0.009% decrease in volume."   

       A hollow diamond that was about 2œ parts air to 1 part diamond could float at equilibrium partway up a deep, still water column. It would have an overall compressibility greater than that of non-hollow diamonds, but still much less than that of water.
spidermother, Nov 18 2011

       // What is less compressible than water? //   

       Plutonium. And yet, with explosive lenses, a subcritical mass can be compressed into supercriticallity. The achievable change in density is quite remarkable.   

       Does that answer your question ?
8th of 7, Nov 18 2011

       My head just underwent a 0.009% increase in volume.
bungston, Nov 18 2011

       My suggestion would be to point a clear, perforated tube between yourself and the viewing object and inject it with an anionic polymer (Polyacrylimide aka P.A.M.) flocculant solution.   

       It works well to clarify water but not sure if it would be quick enough. There is also the issue of injecting something, even as innocuous as P.A.M., into whatever aqueous environment you're in at the time.
AusCan531, Nov 18 2011

       [AusCan]: professionally; he's a veterinarian and a talented surgeon. To my knowledge, he does not perform arthroscopic procedures in his spare time.
Alterother, Nov 18 2011

       //I have been in water so cloudy I could not see the fingers on my outstretched hand //
You could try showering instead.
TolpuddleSartre, Nov 18 2011


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