Write on water with water!

[dogjones]

This (http://www.livescience.com/scienceoffiction/060726_water_write.html) is quite intriguing, although the article doesn't give much detail.

http://boingboing.net/images/060726_writeA_01.jpg
This remarkable display device consists of fifty water-wave generators surrounding a cylindrical tank 5 feet wide and a foot deep. The wave generators move vertically to produce cylindrical waves. These "pixels" are about 4 inches in diameter and 1.5 inches in height; these form lines and shapes. The AMOEBA device can form all of the roman alphabet, as well as some kanji characters.

[Meffy]

Gives a new meaning to "one whose name was writ upon water," dunnit?

[alfaniner]

I can write my name in the snow, with water. :D

[davefoc]

I agree it's a cool idea, but I'm not sure what the heck you could do with it that would justify the expense.

[Meffy]

Well, you could line the coasts with transducers and cancel out all those thousands of rogue waves that prowl the ocean.

... Or you could use the same gear to make rogue waves should you be so inclined. =^_^=

[edit] Once we have orbital habitats people could look down from, the potential for placing advertisements on the oceans' surfaces might be impressive too.

[davefoc]

Well, you could line the coasts with transducers and cancel out all those thousands of rogue waves that prowl the ocean.

... Or you could use the same gear to make rogue waves should you be so inclined. =^_^=



Those seem like really good ideas. Do you foresee any scalability issues?

[Meffy]

Those seem like really good ideas. Do you forsee any scalability issues?
Yes, but I don't fish so I'll let the people who have to scale them deal with that.

[Overman]

Shopping mall display adds/fountians.

Spell Jesus in the water = even more holy water than churches use = $60 a bottle.

[Dark Jaguar]

Haha! Thing is, the average person just isn't aware of this sort of technology, or even of it's possibility. Someone might see this and say "it's a witch!". I can imagine screams of terror unless there's someone explaining to the audience what they are about to see.

And yes, it could easily be used to make people think they are seeing a miracle. I'd make it say "Odin's Eye Is Watching". That'll offend pretty much any modern religion, unless there are still practicing vikings.

Still though, if they wanted to write on water I have a much easier and cheaper way to do it. It involves a freezer and an ice pick.

[FireGarden]

The Abyss!

[ynot]

I can write my name in the snow, with water. :D
Can we be sure it's written in your own handwriting :D

[ynot]

This (http://www.livescience.com/scienceoffiction/060726_water_write.html) is quite intriguing, although the article doesn't give much detail.
Cool effect but limited in application I suspect. Have had a little brain-wave (pun int.) on a more effective way of writing/drawing in water that may have more practical applications - The water contains thousands of minute coloured beads that are attracted to a matrix of small electromagnets that are placed in a flat plane under the surface of the water. The beads move relatively freely through the water (or any liquid) and are attracted to the particular magnets that are turned on to create letters and shapes. Movement could also be created. Oooops! Should have patented it first. :D

[ynot]

This (http://www.livescience.com/scienceoffiction/060726_water_write.html) is quite intriguing, although the article doesn't give much detail.
Another way of using water to write on water - Thousands of small water jets under the surface of the water that squirt straight up. The force of a jet would cause a bulge in the surface of the water. Multiple jets could “sculpt” the surface in to letters and shapes. A 3D effect should be possible using different forces through the jets. Byeee - I’m off to the patent office.

[ponderingturtle]

Cool effect but limited in application I suspect. Have had a little brain-wave (pun int.) on a more effective way of writing/drawing in water that may have more practical applications - The water contains thousands of minute coloured beads that are attracted to a matrix of small electromagnets that are placed in a flat plane under the surface of the water. The beads move relatively freely through the water (or any liquid) and are attracted to the particular magnets that are turned on to create letters and shapes. Movement could also be created. Oooops! Should have patented it first. :D


Well it might have aplication with other fluids, with etching or a different way to get a shape in plastic with out using molds. I see no reason why it needs to be water after all. the principle should work on any fluid. Could be a differnet way to make 3d models and the like.

[ynot]

Well it might have aplication with other fluids, with etching or a different way to get a shape in plastic with out using molds. I see no reason why it needs to be water after all. the principle should work on any fluid. Could be a differnet way to make 3d models and the like.
Of course. It’s still a very complicated and expensive (but fascinating) way of attaining the end result. Also the shapes that this method could achieve are limited. Don‘t think they could create closed letters such as P or B etc.

[NobbyNobbs]

I find it surprising that, on this forum of all places, people's first reaction is "But what good is it?".

It's a neat idea that no one thought of. It looks cool. Isn't that enough?

Besides, most really useful things started out as something frivolous. To quote...oh, I don't know who, but to quote someone famous, "What use is a newborn babe?"

[Meffy]

Also the shapes that this method could achieve are limited. Don‘t think they could create closed letters such as P or B etc.
Yup, says it can make all twenty-six letters. And some kana too. :-)

[ynot]

I find it surprising that, on this forum of all places, people's first reaction is "But what good is it?".

It's a neat idea that no one thought of. It looks cool. Isn't that enough?

Besides, most really useful things started out as something frivolous. To quote...oh, I don't know who, but to quote someone famous, "What use is a newborn babe?"
My first reaction was “Cool effect”(#12). Why do you take comments regarding the usefulness of things as being negative? It’s just part of overall critical analysis. I don’t know why you find the use of critical analysis surprising in this forum. For me, “It looks cool” is not enough. I also want to understand it, and part of that is understanding is what practical applications it might have.

[ynot]

Yup, says it can make all twenty-six letters. And some kana too. :-)
Cool - To be able to create troughs in the middle of closed waves must have something to do with opposing forces and harmonics. :)

[Rasmus]

Can anyone find a video of this? Pretty please?

[alfaniner]

Cool - To be able to create troughs in the middle of closed waves must have something to do with opposing forces and harmonics. :)


Off topic...

OK, next to mine? I like your avatar the best...

[ynot]

Off topic...

OK, next to mine? I like your avatar the best...
Thanks - I find them both hypnotic. Saw yours at full size before you reduced it to use as an avatar. Just about went cross-eyed trying to keep track of the balls. If only I could get mine to work in real life.

[ynot]

Can anyone find a video of this? Pretty please?
Have extensively Googled for a video with no luck. Given that the letter is only visible for a very short period, and takes about fifteen seconds to create, perhaps a video might not look too impressive (hope NobbyNobbs doesn’t think I'm being negative again).

[Rasmus]

Have extensively Googled for a video with no luck. Given that the letter is only visible for a very short period, and takes about fifteen seconds to create, perhaps a video might not look too impressive (hope NobbyNobbs doesn’t think I'm being negative again).


Oh, I am sure I wil lbe impressed.

But besides being impressed, I just have no idea what goes on during the "forming" of the letter. I understand only that there's waves being created on the rim, and eventually, these somehow lead to the letter or shape being displayed in the middle. I would like to understand just leeeettle bit more, assuming I am capable of that.

Also, I am just curious if the letter forms suddenly from chaos (i.e. slow, criss-crossy waves all over the surface and suddenly they reinforce and cancel each other out in just the right places) or is there a relatively calm surface and the letters slowly rise up?

Oh, and also: The thing is too big! It is far too big! I want one (now, dammit!) but even if I had the kind of money, I'd have nowhere to put it! I would like one for my desk, please. With a USB connection or something, so that it could spell out the subjects of new e-mail messages or something urgently required and useful like that. And I would like to combine it with one of these (http://www.bontana-zimmerbrunnen.de/popup_image.php/pID/2) if possible.

[Meffy]

The interacting waves aren't truly chaotic, just complex. The "letters" are interference patterns -- wonderfully clever ones. There must be some serious physical modeling power in whatever's driving them.

[Rasmus]

The interacting waves aren't truly chaotic, just complex. The "letters" are interference patterns -- wonderfully clever ones. There must be some serious physical modeling power in whatever's driving them.

Yes, indeed.

When I was trying to find a video, I read somewhere that an earlier, similar construct needed some 15 minutes do display a single letter and had difficulties creating straight lines.

So my guess is that this new device is to a large extend due to an increase in computer-performance.

[Meffy]

Fifteen minutes -- wow.

The real importance of this development lies not in making recognizable shapes, I think, but in opening the way to possibly controlling turbulence and similar flow and wave phenomena to some extent.

That and generating rogue waves, of course. :-}

[Dog Boots]

Oh, and also: The thing is too big! It is far too big! I want one (now, dammit!) but even if I had the kind of money, I'd have nowhere to put it! I would like one for my desk, please. With a USB connection or something, so that it could spell out the subjects of new e-mail messages or something urgently required and useful like that. And I would like to combine it with one of these (http://www.bontana-zimmerbrunnen.de/popup_image.php/pID/2) if possible.

I know how you feel.

I just know I'll buy myself a plasma cutter someday, though I have absolutely nothing to use it for...just because it's such a cool invention! :)

[NobbyNobbs]

My first reaction was “Cool effect”(#12). Why do you take comments regarding the usefulness of things as being negative? It’s just part of overall critical analysis. I don’t know why you find the use of critical analysis surprising in this forum. For me, “It looks cool” is not enough. I also want to understand it, and part of that is understanding is what practical applications it might have.


I didn't say "negative". I just said...oh, I don't know what I said. But rather than "Neat!", the first thing most people wrote was "Why?"

Now, "Why" is a good question most of the time, but some things don't need purpose. Just enjoy them. That's often purpose enough.

[ynot]

I didn't say "negative". I just said...oh, I don't know what I said. But rather than "Neat!", the first thing most people wrote was "Why?"

Now, "Why" is a good question most of the time, but some things don't need purpose. Just enjoy them. That's often purpose enough.
I understood the point you were making first time around. I wonder if you made any attempt to understand my response?

[Dilb]

But besides being impressed, I just have no idea what goes on during the "forming" of the letter. I understand only that there's waves being created on the rim, and eventually, these somehow lead to the letter or shape being displayed in the middle. I would like to understand just leeeettle bit more, assuming I am capable of that.

Aha! Time for partial differential equations knowledge to come to use!

The surface of water is discribed by the wave equation (http://en.wikipedia.org/wiki/Wave_equation). Nice solutions to the wave equation depend on the geometry. In one dimension (like a string) nice solutions are sines and cosines. In two dimensions, in a circle (like on the pool of water), nice solutions are Bessel functions, which are similar to sines, except they decrease as they get further out, and a few other things.
What makes these 'nice' is that they satisfy the differential part of the wave equation exactly. For example, if an ideal guitar string intially is shaped like a sine function, it won't change in time, except to uniformly move back and forth (a standing wave (http://en.wikipedia.org/wiki/Standing_wave)). What's more, if instead it's shaped like two sine functions put together, each individual sine part of the shape won't change in time, although they will change at different frequencies.

The remarkable part is that you can show that any shape can be created by adding these 'nice' solutions together, in a Fourier Series (http://en.wikipedia.org/wiki/Fourier_series) (checkout the animation). So essentially all you need to do is look at the types of Bessel functions your wave generators make, and add together the right functions so that they make whatever shape you want.

Actually I'm sure it's more complecated, what with the fact that Bessel functions discribe the size of the wave given the radius, and other functions (I think it's sines/cosines) define the wave give the angle of the circle, and there's probably something you need to correct for because of losses, or the fact that the wave equation changes depending on the height of the wave, but I think that's the general idea.