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Science: Fluid Mechanics
The other spin pattern   (+5)  [vote for, against]
shoot balls through thick medium at a wall with two gaps.

Balls can spin given a conducive environment. I am just wondering what the detected patterns would be if instead of marbles, that can't gain any spin drift, a ball/environment is used that allows mechanical spin.

The balls would have to be in a fluid medium to allow for exaggerated spin motion and be neutrally buoyant The ball gun would apply spin and shoot the balls towards a wall with two gaps the size to allow the balls through without touching. Another wall behind in the fluid will mark the balls hit position from trajectory.

Does the fluid affect the pattern? Is there wall, fluid, ball interaction? Is there memory motion in the fluid for the next ball?

Mechanics, nothing here is quantum.
-- wjt, Jul 24 2020

A question that can't be answered straight up and needs an idea of a physical experiment is definitely interesting. If you can mentally calculate the outcome pattern, you are far better than I.

Oh, thanks for the fully thought thru [-]
-- wjt, Jul 25 2020


I'm bunning this because I'd like to play with it, but, if you're not trying to turn your balls into waves, then why two gaps?
-- pertinax, Jul 25 2020


Two gaps might have a strange fluid play compared to just one, Some sort of hydraulically locking with one.*

* wildly guessing
-- wjt, Jul 25 2020


If we're doing hydraulics, then we've got an incompressible fluid inside a sealed system, right?

This sealed system will have to encompass both sides of the wall, and the guns.

What sort of launcher would you recommend for remote operation while immersed in goo? At least, I assume remote operation, unless you're standing in the goo, inside the sealed unit, in a deep-sea diving suit, like last Wednesday.
-- pertinax, Jul 25 2020


// What sort of launcher //

Magnetic "rail gun" would be one option. The other would be an externally driven pusher piston with the volume behind the piston being vented to the surrounding fluid.

But square-law resistance will greatly limit achievable launch velocities, which will decay very quickly after launch.

This idea has all the characteristics of a "thought experiment", except without any actual thought ...
-- 8th of 7, Jul 25 2020


/vented to the surrounding fluid/ There in lies the problem of disturbance with balls spin path. Magnetics seems very controllable but adds an unknown with the magnetic ball dragging a field through the fluid.

The velocity and size of the ball has to be matched to the correct level of viscosity of fluid. Idealy the fluid almost has to a gas-like liquid.

A finite element model could initiate an instantaneous moving spinning ball aimed two doored wall initiated with a still medium. The interesting bit is when the ball traverses the door and how the fluid dynamics pan out to affect trajectory.
-- wjt, Jul 25 2020


// a gas-like liquid //

You'd be better trying to find a liquid-like gas.

Some permanent gases at extreme pressure exhibit significant viscosity. If you look deep in Jupiter's atmosphere you may find something suitable.
-- 8th of 7, Jul 25 2020


A pitching machine inside a supercritical fluid filled vessel, under review by high speed filming.
-- wjt, Jul 25 2020


[+] for playing with the idea of a new experiment. No such thing as an experiment that doesn't render information. Is it useful information? Depends on what you do with it.
-- doctorremulac3, Jul 25 2020


// No such thing as an experiment that doesn't render information. Is it useful information? //

Indeed; even if it's just the sole survivor saying to themselves, "Well, that was a mistake ... never going to try THAT again ..."
-- 8th of 7, Jul 25 2020


My point exactly.
-- doctorremulac3, Jul 25 2020


Nuclear spin in no way resembles the spinning of a pool ball.
-- Voice, Jul 25 2020


Why is pool not played in a pool?
-- pocmloc, Jul 25 2020


[Voice]I have stated that. I imagining more the wave patterns off the the ball's motion in the fluid and it's downstream actions. Some renaming is called for, nspin?

[pocmloc] Viscosity and game period. Although a fluid that changed colour under various pressure waves might balance out the slowness of wet pool. Athough, a game where just traveling past can sink a ball, is intriguing.
-- wjt, Jul 26 2020


// mechanical spin that acts the same as quantum mechanical spin

interesting. might be a bit tricky to get the balls to "add" and "subtract" spin.

how about this:
a "tennis ball wave" launcher which is like a grid of potato cannons or an old-style cannon. it launches a few hundred tennis balls, simultaneously.
let's say, hypothetically, that the balls are not spinning after launch.
the balls are fired at a rectangular opening.
is there interference?
perhaps. the tennis balls will collide with the opening, and with each other.

the thing is, for quantum mechanical objects, the "interference" still happens even if only one tennis ball is launched at once. in other words, every particle acts like a complex-valued probability wave, and the probability of finding an object in any location is the magnitude of that wave.

how to model that?
instead of tennis balls, use custard which contains a cat.
the custard nozzle cannot launch a discrete particle of custard. instead it must launch an entire sheet of custard, thicker in some places and thinner in others, but when the custard hits anything the cat emerges and eats the custard.
until the custard runs into something else it's not clear where inside the custard the cat is located. the cat is probably where the custard is thickest, but could be anywhere.
if two particles of cat-containing custard are launched at a wall at the same time, the cats might interfere constructively or destructively. in some places the cats will be "in phase" and you'll see two cats after they eat the custard. in other places the cats will be "out of phase" and after eating the custard they will get spooked and run away leaving no custard.

i hope this explanation is useful and not too incorrect.
-- sninctown, Jul 28 2020


Explanation ? We read it as a funding application.

Which is, by the way, approved. Please send details of the equipment and facilities you require. We will also supply the custard, the cats, and a selection of impervious surfaces to act as targets.
-- 8th of 7, Jul 28 2020


You mean, you'll find somebody else to supply the cats. I don't believe for a moment that you would handle them yourself...
-- neutrinos_shadow, Jul 29 2020


I was going to mention my lack of quantum knowledge but cats have been mentioned so fair game.

Has probability got a physics definition like nspin? I thought probability is an abstraction of deterministic action because the action is hidden or yet to be known. Five blacks balls, one white, moving around in the bag ready to be drawn. Getting a white ball 1/6 of the time doesn't tell what has happened in the bag.

Maybe, summing up all the black bags across the universe is how the finite improbability drive works. That and a strong cup of tea.
-- wjt, Jul 30 2020


It's a mathematical abstraction to predict probabalistic behavior, verified by observation of outcomes.

Though the term "spin" is used, any number if mutually exclusive labels for inferred properties can be used. The description of the thing is emphatically not the thing itself.
-- 8th of 7, Jul 30 2020


//the term "spin"//

But to choose a name for a thing, that already has an attachment usually implies a logical connection. If there isn't that connection, it's putting understanding on the back foot. Should we call hinges, doorways? Builder install three doorways.

So the electron is still traveling around the nucleus ? but it's path is so unknown that it is abstracted to cloudy probabilistic stuff to step away from the known orbital type object. Or is the representation is real? an electron is just an outcome result of something more nebulous. A finite improbability black bag soup of black and white balls until touched.
-- wjt, Jul 30 2020


//the term "spin"//

Nonsense! Next you'll be saying that charm quarks aren't charming
-- hippo, Jul 30 2020


Or made of quarg.
-- pocmloc, Jul 30 2020


Spin is an previously established ball physics term and can be read as is in the sentence without noticing. Charm maybe of the physics of love but is sufficiently different as to spark a definition look up.

I would have thought scientific words would try to obtain one very accurate meaning.

Actually 'spin' should be the full 'spin state'. So a general public widely used word that defines nuclear spin state, I suggest, would help physics.
-- wjt, Aug 01 2020


[kdf] As for your links, those calculations are for a pure flow system, only focused on the object. This is is more about the wave interactions of the surrounding objects, as the spinning ball passes through a close gap. Designing surf beaches or the finite element analysis territory.
-- wjt, Aug 01 2020


What if we replaced the wall with a floor?

This would mean we could fill the space under the floor with the incompressible fluid, and still leave two holes through which spinning balls could be launched.

There would be backsplash, but there might also be something going on broadly analogous to hydraulics.

What instrumentation might then be used to see what was happening with shock waves in the fluid?
-- pertinax, Aug 06 2020



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