Acoustic Suspension of Water Droplets

by NightHawkInLight

20K27121

Intro: Acoustic Suspension of Water Droplets

Water drops can be suspended on a liquid surface indefinitely by using acoustic vibrations to prevent the surfaces from merging. I used fairly simple parts for this project. The most expensive item is a stereo amplifier, but they are a common find in resale shops for under $10. I found mine for $6. I used an online tone generator to produce the frequencies which can be found here: http://plasticity.szynalski.com/tone-generator.htm

In this video I ran the speaker at 285 Hz and varied the volume to produce the different effects. There is nothing particularly special about 285 Hz, the drops will stay suspended at other frequencies as well. Any dish soap will also work just as well as another to lower surface tension which increases the stability of the drops.

The 4 inch speaker and 90mm petri dish were both purchased online. Often 90mm petri dishes are labeled and sold as 100mm, which are more common to find. The ones I purchased were also being sold as 100mm, but the actual size could be determined by the reviews. Blunt tip syringes were also purchased online to create the drops.

Be aware that this experiment does involve both water and electricity, so there are potential hazards involved. It should not be attempted unless you are familiar with properly dealing with such hazards.

I first learned of this experiment from slow motion footage recorded by Roberto Zenit, National Autonomous University of Mexico. You can check out his footage here.

21 Comments

Maluvaz 7 years ago

Whats the theory for this experiment??

Himers 9 years ago

This is sweeeet!!!

simonero96 9 years ago

https://www.youtube.com/watch?v=kLfV5PeJtUk

NightHawkInLight 9 years ago

Is that your video? Neat. I had only ever seen it done in the video by the University of Mexico as posted above.

simonero96 9 years ago

Yeah,me and some other people studied this phenomenon and bringed our work to a science fair.
I suggest you to try this even with baby oil, frequencies will change a bit but the behaviour of droplets will be much more interesting

Gr8Gr1000Pop 9 years ago

sorry, do not know how to cancel this box

shubham_bhatt 9 years ago

thanks man i was searching for something like this...... your follower for life (YFFL)

fixfireleo 9 years ago

i've seen this done with, i think, sand instead of water and different waves form different patterns. they used a flat plastic hard smooth surface instead of the petri dish...maybe 8x8 or 10x10?

wobbler 9 years ago

This was fascinating. I noticed that you got a pattern when you got the spontaneous droplets. Did you consider or try putting in two separate tones to see if it generated more complex but regular patterns?

wobbler 9 years ago

Let me know if you do try it, I'd be interested in seeing the results, even if it fails as an elimination is as important as a positive, as I'd find it difficult to set this up where I am.

It could also be interesting to try different shaped containers if this is anything to go by as I'm sure there's a similar effect going on in the water with your experiment, or maybe putting shaped islands in the Petri dish:

This would make a great school science project!

GrumpyOldGoat 9 years ago

I can see the square platform mounted on a gimbal system with a solid pendulum to auto-level the surface and allow for tilting by moving the pendulum in different directions to control the direction of flow of the sand.

A fence around the outside perimeter would contain the sand and help keep momma happy.

omnibot 9 years ago

Interesting. I expect your mom and brother are a bit older than you, having lost some hearing in the high frequencies. I'm 37 and I've noticed how I've lost some higher frequencies above 16kHz but gaining an ability to see light flickering beneath 40Hz.

ccronkhite 9 years ago

There are actually devices based on this that are supposed to keep teens and younger adults out of parks at night. They emit a high frequency tone that cannot be heard by most older people but is quite annoying to anyone who can hear it.

jreauclaire 9 years ago

Yes, I would also expect that your mom is a bit older than you. Just a guess.

tomatoskins 9 years ago

This is really cool! I love seeing things like this.

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