I know you can increase water pressure enough to cut marble at quarrys and glass at factories.
It that done in a way comparable to laser light? Where you line up the waves? or is the water just jumbled.
Completely different. You know, of course, that two objects can’t be in the same place at the same time (in its more detailed theoretical form, this is the Pauli Exclusion Principle). In addition to solid objects, this also applies to things like water molecules: You can’t have more than one stream of water in the same place at the same time. If you try it, you’ll just get a bigger stream. However, this does not apply to light. In a laser, you do actually have photons in the same place (and in the same state) at the same time. All of the light in a laser is acting sort of like it’s all the same photon, which is something that water can’t do.
Now, you could have something comparable to a water-jet cutter, using light. If you made a light source bright enough, it could cut through things, even if it wasn’t a laser. But jumbled sources like that (whether of water or of light) tend to disperse and interfere with themselves, so they’re not as efficient. With water, we accept this, since we have no choice. But with light, we can make it more efficient, so we do so.
Hmmm. I’d bet you can’t get two photons to be in the same place at the same time. How could they then be differentiated from a twin or super-photon, which I’ve never hear of? Clearly, they are simply small enough to be side by side.
Nope. It’s literally part of the definition that they can be in the same state.
This may be opening up a big can of heisenberg worms in the thread, but is “the same quantum state” really comparable to “the same place?” I know know this physics stuff, just thought I’d ask.
Location is part of the quantum state. A particle may or may not have a definite location, but to the extent that it does, it’s part of the state. As it happens, photons in a laser have only a very poorly-defined position, but they’re all poorly-defined in the exact same way.
The laser basically makes light brighter. Would a “waser” make water “wetter”? 
Why yes! Yes, it would.
In fact, I expect the manufacturers of bottled mineral water and homoeopathic remedies to cash in on this very soon.
But lasers don’t make light brighter, it just bundles it together more efficiently.
Making water wetter isn’t a good analogy anyway but you can do that by adding anything that breaks down the surface tension. This allows water to more easily wet surfaces that it might otherwise just bead up on.
As Chronos wrote, light an water are entirely different. Light is the result of the action of electric and magnetic force fields. Water is a material substance on the macro level.
However water waves can certainly be synchronized in phase so as to produce huge rogue waves 100 ft. high.
Is water a boson or a fermion? Does it even make sense to speak of such properties for molecules? Would a watery Bose-Einstein condensate have peculiar cutting properties?
You’re not going to make water more “intense” in the same way that light can be made more intense. As noted above, it’s like comparing apples and oranges. Or photons and molecules.
One way you can make water more usable for cutting things, besides increasing the pressure, is to add things to it. Not as scientifically sexy as “laserizing” water, I suppose, but a lot more practical.
One additive is polyoxyethylene, a plastic marketed under the name Polyox. Its “backbone” consists of two carbons (singly bonded to each other, with the other bonds saturated with hydrogen) followed by one oxygen, repeated endlessly. Whereas alternating carbons and oxygens (even with an occasuional double carbon) makes acetal, a tough, water-resistant plastic, polyox is a water-soluble plastic that can be added tro water to lower its resistance to flow and make it cohere better. Without polyox, pressurized water has a tendency to break inmto a spray. With it, the water stays in a thin stream that can cut with precision. If you add a little abrasive grit now, you have a potent cutting tool.
Just to clarify, that would make polyox
H H
| |
... -O-C-C- ...
| |
H H
, correct?
And strictly speaking, a molecule can be a fermion or a boson, and strictly speaking, the most common isotopes would make a water molecule a boson. But by the time you get to the scale of a molecule, the fermion-ness of the component particles is generally much more important than the boson-ness of the whole molecule. If you did somehow manage to produce a watery B-E condensate, though, I can almost guarantee you that all of its properties, cutting and otherwise, would be peculiar.
I’d settle for peculiar properties.
Perhaps if all the water molecules were lined up in tight rows they would be able to travel much farther in a straight line. Whatever they scatter (like the air) would be unable to regroup behind the assault of endless waves. Like a phalanx of soldiers.
And then you could use this super-stream of water to shoot high into tall buildings to fight fires with pinpoint accuracy.
Non-physics person here… but…
Isn’t all matter (water included) primarily consisting of empty space? Since water is more malleable that, say, wood or metal, why couldn’t press and press water to release the empty space… does a firehose do this already? What are the functional limitations toward pressing water to reduce space between water molecules?
if you use an icicle to stab someone, the evidence melts away!
the perfect crime.
From http://science.howstuffworks.com/question553.htm
It’s interesting that they use the word “coherent,” the same word often used to describe the light in lasers. However, HSW does not define what “coherent” means with regard to water.
They mean concentrated in a thin, well-defined stream, and not splaying out, as I noted in my post above. Good nozzle design is needed here. Adding something like PolyOx, to effectively increase the cohesion of the water, helps too.
From this site: http://www.dow.com/polyox/
If you look around, you see they recommend it for cutting the fluid drag for “water jet cutting”, but they no onger seem to list it as a major use.
This isn’t the only product sold for this purpose.
They’re likely using the term to describe the laminar flow you get at a low Reynolds number. It’s not a proper use of the word, but still gives the flavor of what’s going on, without introducing complications.
No it is not comparabel. Water cuts edue to the high pressure and the coherencey as mentioned elsewhere refers to the jet of water staying together because of the nozzele design rather that spreading out in a conical shape.