Moving Particles with Vibration, Making the Chladni Plate

Maybe you need the physical equivalent of an impedance matching network?

"Honey - - where's the salt?"... errrrr

Brian Ullmark

I have been thinking about this effect and its possible implications. I am probably a complete IDIOT! when I contemplate this but; if the output power of the speakers is degraded into sound waves vibration heat and as shown here, geometric shapes, couldn't it be possible to gain some sort of amplification if we add a geometric shape into the system, just as if we added any of the other elements of the energy back to the system? Kind of how a bandpass box sort of amplifies sound waves, but instead maybe in higher frequencies and in a feedback loop configuration...

Hey Mehdi, you're missing your big opportunity to be modern. Place a bunch of small speakers under the plate. The volume and frequency being sent to each speaker would be controlled by an AI system that maximized the amount of material falling off one edge. Voila, you solved a problem without high level thinking or solving a partial differential equation.

Very cool Mehdi. Did you try to set the two speakers at 2 completely different frequencies? You mentioned that a plate can have multiple resonant frequencies, so what happens when you set the speakers to 2 different resonant frequency? Or maybe set one to the resonate frequency + 1%, and the other to -1%?

now do it with a concert speaker

Zephy Foxy

Couldn't you use a slowly increasing frequency? Wouldn't the particles then be slowly pushed along by the peak of the wave ? I'm thinking a slowly increasing frequency that then drops to near zero and starts again. I feel a distraction coming on this weekend... where does she hide the salt.

To move the node continuously, you roll the phase continuously, which is identically equivalent to changing the freq. by the roll rate.

Clamping the edge will actually still cause reflections. If the edges are free, you get an exact reflection. If they are clamped, you get an inverse reflection. To eliminate reflections, you need a tuned dampener, i.e. a 'clamp' as you say, but one that is allowed to move around a little to absorb the wave instead of reflect it. Theoretically, cutting the board properly could also eliminate reflection, but finding the right cut can be challenging.

You were sooo close, Mehdi! The speakers at either end have to be the same frequency. You shift the *phase* of one of them to make the salt move. As you mentioned, you also have to eliminate reflected waves. You do this by (here comes an electronics analogy) matching the impedance of each speaker (not electrical impedance, but physical impedance, i.e. the rate at which the wave travels through the material, or speakers). Since the physical impedance of the speakers is fixed, you should be able to achieve an impedance match by trying different densities of materials. I made this circuit to demonstrate: http://tinyurl.com/y5kgwngp On the right, the bottommost slider adjusts the phase of the right-hand input. You can see that as you move the slider (slowly, as you have to give the wave time to propogate), the node at the center of the transmission line will shift. 360 degrees of shift should move the node one half wave length. Note that the impedance of both inputs, and the impedance of the transmission line are all the same. Furthermore, the transmission line is exactly 2 wavelengths (i.e. the wave is ressonant). The higher ressonant frequency you use, the tighter your salt lines will be too. Edit: I tweaked it a bit so it's a little easier to see. Apparantly, the length of the material (or distance between the speakers) doesn't matter, as long as impedances are matched: http://tinyurl.com/y5qyhly2 As for those little clouds that appear, condense, appear, condense; I have no idea what's going on there, but I really, really would like to find out. My best guess is that the vibrations have pulverized/vaporized the NaCl, and since NaCl molecule is extremely polar, the molecules tend to want to stick back together, so once the vibrations stop pummelling them, they quickly condense back into little salt piles.

If you cut the ends of the boards at different angles, then you can pretty much avoid standing waves. I would suggest mounting your actuators within the board area and using a larger board then you need. Alternatively, you could use a large board and rigidly clamp the edges to enforce edge nodes and avoid reflections.

:D

ElectroBOOM [Mehdi Sadaghdar]

I posted too soon, I should finish your video before I post. Great experiment!! I want to play with this idea more.

Ron Jones

Use two speakers, each with its own controlled oscillator. You may be able to get a standing wave with nodes that will collect particles and the second speaker may give you control to move the node back and forth at your will. I don't know, it is just an idea that I think I will try.

Ron Jones

That is a good clickbaity idea!

ElectroBOOM [Mehdi Sadaghdar]

A plate is like a low pass filter. Above some frequency it can't physically vibrate anymore.

ElectroBOOM [Mehdi Sadaghdar]

What will happen if you use a rather high frequency like in KHz or MHz😅😅

Such a great vid as per usual! Keep it up ElectrBoom!

With sugar this can be sweet move.

Great video as always!

Whatever floats your boat!

ElectroBOOM [Mehdi Sadaghdar]

Physics Girl? Pah... I want to see the hairy man!

Like a holy spirit through a wall. Yes, I get it now.

You should change the title, "Moving Particles with Vibrators" 😂

PseudsPie