Bouncing liquid surface can make bubbles do a stop-start dance

Bubbles driven around on liquid surface by sound waves.

Read the whole story

 

[redtomato]

I never realised that the inkjet printer is the natural enemy of the Chris Lee. It all makes sense now. Laser printers forever!

 

[Sarty]

If we limit our set of physical phenomena to only the ones that a five-year-old has seen or experienced, I think that surface tension is the clear answer to the question "how can we immediately make really odd things happen?".

 

[Wickwick]

I don't think the microfluidics example is going to hold up. When you bounce a droplet of water around, it's not the same water molecules each time. Just like a wave can pass thousands of kilometers across the ocean but the individual water molecules never have to move more than the wave height. It's the momentum that moves through the fluid, not the mass. And when that momentum focuses, a blob of water can be ejected.

Besides, we can already create the individual single drop collision isolation that Chris was suggesting. In fact, these sorts of drop-on-drop impingement experiments were done in the 90's using ... inkjet printer heads.

 

[purfledspruce]

Obligatory link to Don Petit's playing with water droplets in space. Droplets start at 1:05 in the video. It's fascinating.

https://www.youtube.com/watch?v=fWS0zWQ8DP4

 

[tresclow]

Elizabeth Holmes is interested.

 

[A.Mikulan]

I always saw these bubbles in the floor while taking a shower, but I never knew what they were. Thanks Chris Lee!

 

[Not Sid Haig]

This can't be a typical Chris Lee article. Usually those are both visually appealing and generally inscrutable, and I don't think I got any smarter since the last one.

 

[pusher robot]

These are the phenomena that model many quantum effects in Newtonian scale, are they not?

 

[PhaseShifter]

Essentially, the frequency of vibration and the spacing of the valleys vary in a fixed ratio

This doesn't sound quite right to me.
At a fixed speed, the wavelength is inversely proportional to the frequency, not directly proportional.

Of course surface waves in liquids don't all propagate at the same speed--the restoring force is a combination of gravity and surface tension. These don't scale the same way with frequency, so higher frequencies tend to propagate faster. (You can easily see this by tossing a pebble into a pond, or comparing what happens when you slosh your coffee cup from sided to side vs tapping it on the side with a pencil)

 

[Hookgrip]

Personally, I think this is just a cool demonstration of the power of fluid dynamics and a fun experiment. But, if I were trying to convince people to give me money, I would discuss microfluidics.

Personally, I think this is one of the best ways of summarizing an article. But, if I were trying to convince people to give me money, I would recommend all Ars subheadings use this format.

 

[Wickwick]

Essentially, the frequency of vibration and the spacing of the valleys vary in a fixed ratio

This doesn't sound quite right to me.
At a fixed speed, the wavelength is inversely proportional to the frequency, not directly proportional.

Of course surface waves in liquids don't all propagate at the same speed--the restoring force is a combination of gravity and surface tension. These don't scale the same way with frequency, so higher frequencies tend to propagate faster. (You can easily see this by tossing a pebble into a pond, or comparing what happens when you slosh your coffee cup from sided to side vs tapping it on the side with a pencil)

The propagation of surface waves depends on how deep the liquid layer is. If the depth is much, much greater than the wavelength, there is a frequency dependence. However, for shallow waves, only the depth matters and the propagation speed is independent of frequency. All these works are in the shallow-wave regime.

Reference: the wiki on gravity waves.

 

[Urist]

 

[TheNewShiny]

Obligatory link to Don Petit's playing with water droplets in space. Droplets start at 1:05 in the video. It's fascinating.

https://www.youtube.com/watch?v=fWS0zWQ8DP4

Very cool, but it's begging for a do-over with higher fps and super slo-mo replay. Even just a phone could do better these days.

 

[sarusa]

I never realised that the inkjet printer is the natural enemy of the Chris Lee. It all makes sense now. Laser printers forever!

I realize the humor value, but inkjet printers are the natural enemy of everyone.

Laser printer:
- Sitting here totally quiet. It's years old, never needed a cartridge change.
- Print a dozen pages
- It fires up, even though it's been idle for two weeks
- First page printed in 5 seconds, all printed in 20 seconds
- It goes back to sleep
- It just works

Inkjet Printer:
- Sitting here making occasional disturbing noises (as it tries to maintain the head, wasting ink)
- Print a dozen pages
- It fires up
- Since it's been idle for two weeks, it goes into deep maintenance mode
- Sits there whirring and sucking for two minutes, eats a tenth of the tiny ink cart
- Starts printing. Whunk chunk. Whunk chunk.
- First page is done. Oh look, nozzles are still clogged, streaks everywhere
- Cancel the print
- Do a cleaning. Two more minutes of whirring and sucking, another tenth of the ink gone
- Try printing again
- It doesn't realize I just did a cleaning, since I cancelled the last one it decides to do another cleaning
- Two minutes (etc)
- 'Black cartridge is out of ink'
- Drive out to the desert with the printer and an automatic weapon
- It never just works

I worked on Inkjet printers for 10 years, so I know how terrible they are.

 

[Wickwick]

I never realised that the inkjet printer is the natural enemy of the Chris Lee. It all makes sense now. Laser printers forever!

I realize the humor value, but inkjet printers are the natural enemy of everyone.

Laser printer:
- Sitting here totally quiet. It's years old, never needed a cartridge change.
- Print a dozen pages
- It fires up, even though it's been idle for two weeks
- First page printed in 5 seconds, all printed in 20 seconds
- It goes back to sleep
- It just works

Inkjet Printer:
- Sitting here making occasional disturbing noises (as it tries to maintain the head, wasting ink)
- Print a dozen pages
- It fires up
- Since it's been idle for two weeks, it goes into deep maintenance mode
- Sits there whirring and sucking for two minutes, eats a tenth of the tiny ink cart
- Starts printing. Whunk chunk. Whunk chunk.
- First page is done. Oh look, nozzles are still clogged, streaks everywhere
- Cancel the print
- Do a cleaning. Two more minutes of whirring and sucking, another tenth of the ink gone
- Try printing again
- It doesn't realize I just did a cleaning, since I cancelled the last one it decides to do another cleaning
- Two minutes (etc)
- 'Black cartridge is out of ink'
- Drive out to the desert with the printer and an automatic weapon
- It never just works

I worked on Inkjet printers for 10 years, so I know how terrible they are.

But inkjet print heads can also be used to make OLED screens. I haven't seen a laser printer do that.

 

[All4vols]

This can't be a typical Chris Lee article. Usually those are both visually appealing and generally inscrutable, and I don't think I got any smarter since the last one.

One doesn't get smarter reading a Chris Lee article. You can only become more educated. And by that I mean, you learn how stupid you really are. See, I used to think I was pretty smart. I graduated with an accredited degree in a science after all. But now decades later reading Chris's articles, I realize I only know how to memorize and that I'm really not all that smart.

 

[Virkash]

I never realised that the inkjet printer is the natural enemy of the Chris Lee. It all makes sense now. Laser printers forever!

I realize the humor value, but inkjet printers are the natural enemy of everyone.

Laser printer:
- Sitting here totally quiet. It's years old, never needed a cartridge change.
- Print a dozen pages
- It fires up, even though it's been idle for two weeks
- First page printed in 5 seconds, all printed in 20 seconds
- It goes back to sleep
- It just works

Inkjet Printer:
- Sitting here making occasional disturbing noises (as it tries to maintain the head, wasting ink)
- Print a dozen pages
- It fires up
- Since it's been idle for two weeks, it goes into deep maintenance mode
- Sits there whirring and sucking for two minutes, eats a tenth of the tiny ink cart
- Starts printing. Whunk chunk. Whunk chunk.
- First page is done. Oh look, nozzles are still clogged, streaks everywhere
- Cancel the print
- Do a cleaning. Two more minutes of whirring and sucking, another tenth of the ink gone
- Try printing again
- It doesn't realize I just did a cleaning, since I cancelled the last one it decides to do another cleaning
- Two minutes (etc)
- 'Black cartridge is out of ink'
- Drive out to the desert with the printer and an automatic weapon
- It never just works

I worked on Inkjet printers for 10 years, so I know how terrible they are.

But inkjet print heads can also be used to make OLED screens. I haven't seen a laser printer do that.

Yeah well a laser head could totally destroy OLED screens.

 

[KingKrayola]

I never realised that the inkjet printer is the natural enemy of the Chris Lee. It all makes sense now. Laser printers forever!

I realize the humor value, but inkjet printers are the natural enemy of everyone.

Laser printer:
- Sitting here totally quiet. It's years old, never needed a cartridge change.
- Print a dozen pages
- It fires up, even though it's been idle for two weeks
- First page printed in 5 seconds, all printed in 20 seconds
- It goes back to sleep
- It just works

Inkjet Printer:
- Sitting here making occasional disturbing noises (as it tries to maintain the head, wasting ink)
- Print a dozen pages
- It fires up
- Since it's been idle for two weeks, it goes into deep maintenance mode
- Sits there whirring and sucking for two minutes, eats a tenth of the tiny ink cart
- Starts printing. Whunk chunk. Whunk chunk.
- First page is done. Oh look, nozzles are still clogged, streaks everywhere
- Cancel the print
- Do a cleaning. Two more minutes of whirring and sucking, another tenth of the ink gone
- Try printing again
- It doesn't realize I just did a cleaning, since I cancelled the last one it decides to do another cleaning
- Two minutes (etc)
- 'Black cartridge is out of ink'
- Drive out to the desert with the printer and an automatic weapon
- It never just works

I worked on Inkjet printers for 10 years, so I know how terrible they are.

But inkjet print heads can also be used to make OLED screens. I haven't seen a laser printer do that.

Doesn’t that also mean cheap, widespread OLED screens would have been a thing a decade ago if they could be made on a laser printer?

 

[Wickwick]

I never realised that the inkjet printer is the natural enemy of the Chris Lee. It all makes sense now. Laser printers forever!

I realize the humor value, but inkjet printers are the natural enemy of everyone.

Laser printer:
- Sitting here totally quiet. It's years old, never needed a cartridge change.
- Print a dozen pages
- It fires up, even though it's been idle for two weeks
- First page printed in 5 seconds, all printed in 20 seconds
- It goes back to sleep
- It just works

Inkjet Printer:
- Sitting here making occasional disturbing noises (as it tries to maintain the head, wasting ink)
- Print a dozen pages
- It fires up
- Since it's been idle for two weeks, it goes into deep maintenance mode
- Sits there whirring and sucking for two minutes, eats a tenth of the tiny ink cart
- Starts printing. Whunk chunk. Whunk chunk.
- First page is done. Oh look, nozzles are still clogged, streaks everywhere
- Cancel the print
- Do a cleaning. Two more minutes of whirring and sucking, another tenth of the ink gone
- Try printing again
- It doesn't realize I just did a cleaning, since I cancelled the last one it decides to do another cleaning
- Two minutes (etc)
- 'Black cartridge is out of ink'
- Drive out to the desert with the printer and an automatic weapon
- It never just works

I worked on Inkjet printers for 10 years, so I know how terrible they are.

But inkjet print heads can also be used to make OLED screens. I haven't seen a laser printer do that.

Doesn’t that also mean cheap, widespread OLED screens would have been a thing a decade ago if they could be made on a laser printer?

The "ink" is the organic material that emits light. It's very expensive but each pixel only needs picoliters.

 

[Darkness1231]

Chris, if we're to go anywhere with your idea for microfluidics we need an answer to the only question that matters:

Is your speaking voice baritone?

If not, can you fake it?

 

[An Inquiring Mind Ponders]

I don't think the microfluidics example is going to hold up. When you bounce a droplet of water around, it's not the same water molecules each time. Just like a wave can pass thousands of kilometers across the ocean but the individual water molecules never have to move more than the wave height. It's the momentum that moves through the fluid, not the mass. And when that momentum focuses, a blob of water can be ejected.

Besides, we can already create the individual single drop collision isolation that Chris was suggesting. In fact, these sorts of drop-on-drop impingement experiments were done in the 90's using ... inkjet printer heads.

Find this subject fascinating, REALLY LOVE THE IDEA OF HAVING TWO MODULATION FREQUENCIES OF THE SURFACE, WHAT A GREAT NEXT STEP IN THESE EXPERIMENTS!

Would suggest from Veritasium:

Is This What Quantum Mechanics Looks Like?

https://www.youtube.com/watch?v=WIyTZDHuarQ

With:

When fluid dynamics mimic quantum mechanics

http://news.mit.edu/2013/when-fluid-dyn ... anics-0729

"Physicists’ inability to detect de Broglie’s posited waves led them, for the most part, to abandon pilot-wave theory. Recently, however, a real pilot-wave system has been discovered, in which a drop of fluid bounces across a vibrating fluid bath, propelled by waves produced by its own collisions.

In 2006, Yves Couder and Emmanuel Fort, physicists at Université Paris Diderot, used this system to reproduce one of the most famous experiments in quantum physics: the so-called “double-slit” experiment, in which particles are fired at a screen through a barrier with two holes in it."

Which caused "Copenhagen interpretation" type of QM people to go Ape S### and respond with:

Famous Experiment Dooms Alternative to Quantum Weirdness

https://www.quantamagazine.org/famous-e ... -20181011/

Oil droplets guided by “pilot waves” have failed to reproduce the results of the quantum double-slit experiment, crushing a century-old dream that there exists a single, concrete reality.

From first article linked a different experiment:

“It’s a great result,” says Paul Milewski, a math professor at the University of Bath, in England, who specializes in fluid mechanics. “Given the number of quantum-mechanical analogues of this mechanical system already shown, it’s not an enormous surprise that the corral experiment also behaves like quantum mechanics. But they’ve done an amazingly careful job, because it takes very accurate measurements over a very long time of this droplet bouncing to get this probability distribution.”

Link to MIT site that has a lot of great info on this subject:

New wave of pilot-wave theory, ect ... (Best site, lots of pictures, videos, how to do it)

https://math.mit.edu/~bush/?cat=19

Pilot-wave hydrodynamics: A review

The hydrodynamic boost factor of walking drops

Walkers in a rotating frame: Orbital stability

Walkers in a rotating frame: Experiments

Hydrodynamic pilot-wave theory

Pilot-wave dynamics of walking drops

Pilot-wave dynamics in a circular corral

Droplets walking on a vibrating fluid bath

ECT

Being a believer in some aspects of the De Broglie–Bohm theory.

De Broglie–Bohm theory

https://en.wikipedia.org/wiki/De_Brogli ... ohm_theory

With Bohm Quantium Trajectories that distort local quantum potentials that act like pilot waves.

https://en.wikipedia.org/wiki/De_Brogli ... lspalt.svg

"In de Broglie–Bohm theory, the wavefunction is defined at both slits, but each particle has a well-defined trajectory that passes through exactly one of the slits. The final position of the particle on the detector screen and the slit through which the particle passes is determined by the initial position of the particle. Such initial position is not knowable or controllable by the experimenter, so there is an appearance of randomness in the pattern of detection. In Bohm's 1952 papers he used the wavefunction to construct a quantum potential that, when included in Newton's equations, gave the trajectories of the particles streaming through the two slits. In effect the wavefunction interferes with itself and guides the particles by the quantum potential in such a way that the particles avoid the regions in which the interference is destructive and are attracted to the regions in which the interference is constructive, resulting in the interference pattern on the detector screen."

This is why some people think that the experiments linked above with walking droplets could have "some type" of analogy to quantum mechanics.

AN

New Support for Alternative Quantum View

https://www.quantamagazine.org/pilot-wa ... -20160516/

Personally I kinda like the possible analogous extensions to Quantium Gravity and the associated visual "Gedanken Experiments" one can play with while keeping the walking droplets in the back of ones mind.

 

[jcolvin]

You can get a very similar effect with coffee in a styrofoam cup if you move it across the table at just the right speed.

 

[jarek1]

Bouncing droplets are also great to imagine wave-particle duality thanks to interaction with coupled wave - there are lots of experiments started by Couder's group, like double-slit interference (pilot wave chooses path), orbit quantization in a few ways (including double: of radius and angular momentum, Zeeman shift), tunneling.

Slides with gathered links (also hydrodynamical analogues to Casimir force, Aharonov-Bohm): https://www.dropbox.com/s/kxvvhj0cnl1iqxr/Couder.pdf

 

[KingKrayola]

I never realised that the inkjet printer is the natural enemy of the Chris Lee. It all makes sense now. Laser printers forever!

I realize the humor value, but inkjet printers are the natural enemy of everyone.

Laser printer:
- Sitting here totally quiet. It's years old, never needed a cartridge change.
- Print a dozen pages
- It fires up, even though it's been idle for two weeks
- First page printed in 5 seconds, all printed in 20 seconds
- It goes back to sleep
- It just works

Inkjet Printer:
- Sitting here making occasional disturbing noises (as it tries to maintain the head, wasting ink)
- Print a dozen pages
- It fires up
- Since it's been idle for two weeks, it goes into deep maintenance mode
- Sits there whirring and sucking for two minutes, eats a tenth of the tiny ink cart
- Starts printing. Whunk chunk. Whunk chunk.
- First page is done. Oh look, nozzles are still clogged, streaks everywhere
- Cancel the print
- Do a cleaning. Two more minutes of whirring and sucking, another tenth of the ink gone
- Try printing again
- It doesn't realize I just did a cleaning, since I cancelled the last one it decides to do another cleaning
- Two minutes (etc)
- 'Black cartridge is out of ink'
- Drive out to the desert with the printer and an automatic weapon
- It never just works

I worked on Inkjet printers for 10 years, so I know how terrible they are.

But inkjet print heads can also be used to make OLED screens. I haven't seen a laser printer do that.

Doesn’t that also mean cheap, widespread OLED screens would have been a thing a decade ago if they could be made on a laser printer?

The "ink" is the organic material that emits light. It's very expensive but each pixel only needs picoliters.

Amazing that we can print hi-res screens now. I was making a crap joke that we would have got there quicker if we could have used a good ol’ LaserJet 4L.

Imagine the cost of a cleaning cycle with OLED ink…

 

[Troglodytes troglodytes indigenus]

There's got to be a parallel in nuclear physics there somewhere.

 

[Wickwick]

I never realised that the inkjet printer is the natural enemy of the Chris Lee. It all makes sense now. Laser printers forever!

I realize the humor value, but inkjet printers are the natural enemy of everyone.

Laser printer:
- Sitting here totally quiet. It's years old, never needed a cartridge change.
- Print a dozen pages
- It fires up, even though it's been idle for two weeks
- First page printed in 5 seconds, all printed in 20 seconds
- It goes back to sleep
- It just works

Inkjet Printer:
- Sitting here making occasional disturbing noises (as it tries to maintain the head, wasting ink)
- Print a dozen pages
- It fires up
- Since it's been idle for two weeks, it goes into deep maintenance mode
- Sits there whirring and sucking for two minutes, eats a tenth of the tiny ink cart
- Starts printing. Whunk chunk. Whunk chunk.
- First page is done. Oh look, nozzles are still clogged, streaks everywhere
- Cancel the print
- Do a cleaning. Two more minutes of whirring and sucking, another tenth of the ink gone
- Try printing again
- It doesn't realize I just did a cleaning, since I cancelled the last one it decides to do another cleaning
- Two minutes (etc)
- 'Black cartridge is out of ink'
- Drive out to the desert with the printer and an automatic weapon
- It never just works

I worked on Inkjet printers for 10 years, so I know how terrible they are.

But inkjet print heads can also be used to make OLED screens. I haven't seen a laser printer do that.

Doesn’t that also mean cheap, widespread OLED screens would have been a thing a decade ago if they could be made on a laser printer?

The "ink" is the organic material that emits light. It's very expensive but each pixel only needs picoliters.

Amazing that we can print hi-res screens now. I was making a crap joke that we would have got there quicker if we could have used a good ol’ LaserJet 4L.

Imagine the cost of a cleaning cycle with OLED ink…

The actual "printers" are about 10 m on a side and 3 or 4 high. The print heads go through a very specific maintenance regime that includes measuring the drop size and tuning the drivers between each batch. Here's a publically-avaiable photo:

 

[numerobis]

So did Chris just have a major deadline pass two weeks ago and is now indulging himself in fun summer reading?

 

[Voyna i Mor]

I never realised that the inkjet printer is the natural enemy of the Chris Lee. It all makes sense now. Laser printers forever!

I really do not get the hate.
Laser printers are almost incredibly wasteful of material, and the cheaper they are the greater the proportion of the printer you have to replace when the toner runs out. The average operating power is in the hundreds or thousands of watts.
Modern inkjets are far less wasteful of materials, use much less power, and have a perfectly adequate throughput.
It isn't reasonable to compare some disposable piece of crap designed for bargain stores to a decent laser printer. You need to compare like with like - which means if you want to compare a $1500 laser, you need to compare it to a $1500 inkjet. Compare, say, an Epson Workforce to a typical mid-range colour laser and see which one has the lowest materials wastage and operating cost.
(rant for the day over)

 

[numerobis]

I never realised that the inkjet printer is the natural enemy of the Chris Lee. It all makes sense now. Laser printers forever!

I really do not get the hate.
Laser printers are almost incredibly wasteful of material, and the cheaper they are the greater the proportion of the printer you have to replace when the toner runs out. The average operating power is in the hundreds or thousands of watts.
Modern inkjets are far less wasteful of materials, use much less power, and have a perfectly adequate throughput.
It isn't reasonable to compare some disposable piece of crap designed for bargain stores to a decent laser printer. You need to compare like with like - which means if you want to compare a $1500 laser, you need to compare it to a $1500 inkjet. Compare, say, an Epson Workforce to a typical mid-range colour laser and see which one has the lowest materials wastage and operating cost.
(rant for the day over)

Why would it be invalid to compare the roughly $100 ink jet to a roughly $100 laser printer? I’ve not even seen a $1500 printer recently; that’s a price from the early 1990s.

 

[cyberfunk]

I see this placeholder for video.. did some editor forget to do their job ? "Sample videos of droplet motion. I recommend the first three: Chasers_7, Promenade_SW_2, and Stop_and_go_1, which show examples of the points I've discussed in the story."

 

[numerobis]

I see this placeholder for video.. did some editor forget to do their job ? "Sample videos of droplet motion. I recommend the first three: Chasers_7, Promenade_SW_2, and Stop_and_go_1, which show examples of the points I've discussed in the story."

I see some unusual web app for the videos, which with clicking on an unlabeled checkbox leads me to a page where I can download them (all 1.1 GB of dancing droplets).

I guess they decided not to host them on a more useful platform.

 

[Azethoth666]

I don't think the microfluidics example is going to hold up. When you bounce a droplet of water around, it's not the same water molecules each time. Just like a wave can pass thousands of kilometers across the ocean but the individual water molecules never have to move more than the wave height. It's the momentum that moves through the fluid, not the mass. And when that momentum focuses, a blob of water can be ejected.

Besides, we can already create the individual single drop collision isolation that Chris was suggesting. In fact, these sorts of drop-on-drop impingement experiments were done in the 90's using ... inkjet printer heads.

I don't think that is correct. The droplet really is the same. The surface tension separates it from the bath. If the tension broke it would reabsorb but it does not. It keeps bouncing. The bouncing is proof of no mixing. There is an air layer providing separation.

I do not know if the sound waveform can be structured enough in practice to do what Chris describes for arbitrarily complicated droplet motions but it sure seems possible.

It makes me wonder if you can do a version of this in space without needing a bath. Just a bunch of droplets moving in the air.

 

[Wickwick]

I don't think the microfluidics example is going to hold up. When you bounce a droplet of water around, it's not the same water molecules each time. Just like a wave can pass thousands of kilometers across the ocean but the individual water molecules never have to move more than the wave height. It's the momentum that moves through the fluid, not the mass. And when that momentum focuses, a blob of water can be ejected.

Besides, we can already create the individual single drop collision isolation that Chris was suggesting. In fact, these sorts of drop-on-drop impingement experiments were done in the 90's using ... inkjet printer heads.

I don't think that is correct. The droplet really is the same. The surface tension separates it from the bath. If the tension broke it would reabsorb but it does not. It keeps bouncing. The bouncing is proof of no mixing. There is an air layer providing separation.

I do not know if the sound waveform can be structured enough in practice to do what Chris describes for arbitrarily complicated droplet motions but it sure seems possible.

It makes me wonder if you can do a version of this in space without needing a bath. Just a bunch of droplets moving in the air.

OK, that's interesting. Unfortunately, Chris' links don't resolve to actual videos. Have an example?

 

[An Inquiring Mind Ponders]

I don't think the microfluidics example is going to hold up. When you bounce a droplet of water around, it's not the same water molecules each time. Just like a wave can pass thousands of kilometers across the ocean but the individual water molecules never have to move more than the wave height. It's the momentum that moves through the fluid, not the mass. And when that momentum focuses, a blob of water can be ejected.

Besides, we can already create the individual single drop collision isolation that Chris was suggesting. In fact, these sorts of drop-on-drop impingement experiments were done in the 90's using ... inkjet printer heads.

I don't think that is correct. The droplet really is the same. The surface tension separates it from the bath. If the tension broke it would reabsorb but it does not. It keeps bouncing. The bouncing is proof of no mixing. There is an air layer providing separation.

I do not know if the sound waveform can be structured enough in practice to do what Chris describes for arbitrarily complicated droplet motions but it sure seems possible.

It makes me wonder if you can do a version of this in space without needing a bath. Just a bunch of droplets moving in the air.

For a reason I find this subject fascinating and jumped down the rabbit hole some more:

Along with the links that I had provided before from MIT:

Lots of info and videos,

https://math.mit.edu/~bush/?cat=19

Good link to paper referenced in article:

https://www.researchgate.net/publication/331181724

Vast information (info and videos) at sites associated with Yves Couder:

http://dotwave.org

And:

https://dualwalkers.com

Best of all a great lecture by Yves Couder that really clears up what is actually going on in understandable detail with a lot of clearly explained videos of different phenomena:

"Yves Couder Wave particle duality as it emerges in the dynamics of a classical particle driven by it"

https://www.youtube.com/watch?v=QvHREXA3cl0

A lot of wickedly interesting nonlinear hydrodynamic phenomena make these things happen and until I watched this video I did not realize how much I was off on my understanding:

1) Faraday waves and how nonlinear hydrodynamics create them and how these experiments are setup to create the "standing Faraday waves".

2) This one is totally wicked ==> Retro-propagating Faraday waves that form the standing Faraday pilot waves, (that retro-propagating phenomena just blows me away).

3) Periodic forcing of the Faraday instability as a temporal Bragg mirror.

4) Temporal phase conjugation mirrors.

5) And it goes on and on, either you are sold at this point or not.

 

[An Inquiring Mind Ponders]

There's got to be a parallel in nuclear physics there somewhere.

If you are referring to the original de Broglie pilot wave quantum mechanics theory and are interested in that, I recommend watching:

"Yves Couder Wave particle duality as it emerges in the dynamics of a classical particle driven by it"

https://www.youtube.com/watch?v=QvHREXA3cl01

And take note of Yves Couder references to it and the parallels to what is going on. Note this in not the Bohmian (de Broglie–Bohm theory) interpretation of GM as that is significantly different from the original de Broglie interpretation.

 

[peragrin]

I never realised that the inkjet printer is the natural enemy of the Chris Lee. It all makes sense now. Laser printers forever!

Ink jet printers are the enemy of everyone.

at one point I found it cheaper to just buy a new printer every 6 months rather than buy ink. as the ink cost more than the printer for the quantities I needed.(minimal)

laser jets can sit there bored and dusty until you need them. and then spit out many pages a second.

 

[cynyc2]

I never realised that the inkjet printer is the natural enemy of the Chris Lee. It all makes sense now. Laser printers forever!

I realize the humor value, but inkjet printers are the natural enemy of everyone.

Laser printer:
- Sitting here totally quiet. It's years old, never needed a cartridge change.
- Print a dozen pages
- It fires up, even though it's been idle for two weeks
- First page printed in 5 seconds, all printed in 20 seconds
- It goes back to sleep
- It just works

Inkjet Printer:
- Sitting here making occasional disturbing noises (as it tries to maintain the head, wasting ink)
- Print a dozen pages
- It fires up
- Since it's been idle for two weeks, it goes into deep maintenance mode
- Sits there whirring and sucking for two minutes, eats a tenth of the tiny ink cart
- Starts printing. Whunk chunk. Whunk chunk.
- First page is done. Oh look, nozzles are still clogged, streaks everywhere
- Cancel the print
- Do a cleaning. Two more minutes of whirring and sucking, another tenth of the ink gone
- Try printing again
- It doesn't realize I just did a cleaning, since I cancelled the last one it decides to do another cleaning
- Two minutes (etc)
- 'Black cartridge is out of ink'
- Drive out to the desert with the printer and an automatic weapon
- It never just works

I worked on Inkjet printers for 10 years, so I know how terrible they are.

But inkjet print heads can also be used to make OLED screens. I haven't seen a laser printer do that.

They are also used in 3D printers. I'm not sure how they work, but they can print multiple colors and "rubberiness*".

*various versions of stiffness...

 

[An Inquiring Mind Ponders]

Since this has turned into an inkjet printer thread:

Bubble Experiment Finds Universal Laws

https://www.quantamagazine.org/bubble-e ... -20190731/