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The weird physics of levitating liquids and upside-down buoyancy [2 Marge!]
Nature video for the doi:10.1038/s41586-020-2643-8.
Vibration overcomes gravity on a levitating fluid
Counter-intuitive phenomena that arise in fluids under the action of vibration have attracted considerable research interest since the 1950s. For example, in a vibrating volume of fluid, gas bubbles can sink and heavy particles can rise. Moreover, a layer of fluid can be levitated above a layer of air by shaking the system vertically at a relatively high frequency (of the order of 100 hertz or more). Writing in Nature, Apffel et al. report another remarkable phenomenon associated with a vibrating, levitated layer of fluid: objects can float upside down on the lower interface of the fluid, as if gravity were inverted (Fig. 1). These phenomena have strong potential for practical use, for example in systems that involve gas bubbles suspended in fluids (such as bubble column reactors used for gas–liquid reactions), and for the segregation and transport of material inclusions in fluids (as used in mineral processing and waste-water treatment).
The extraordinary behaviours of vibrating fluids are just a small fraction of the surprising phenomena that arise as a result of high-frequency vibrations more generally. Probably the most well-documented examples are the Stephenson–Kapitza pendulum, in which a rigid pendulum balances upside down from a vibrating point of suspension, and the Chelomei pendulum, in which a washer that can slide along a rod seems to 'float' when the rod is vibrated vertically.
Kapitza pendulum - the downwards hanging equilibrium position becomes unstable
Chelomei's pendulum explained - a rod with a sliding disc, the ensemble being vibrated vertically.
Whatever Floats Your Boat? Scientists Defy Gravity With Levitating Liquid
Whatever floats your boat? Scientists defy gravity with levitating liquid:
Scientists have turned the world upside down with a curious quirk of physics that allowed them to float toy boats the wrong way up beneath a levitating body of liquid.
In a striking demonstration of the mind-bending effect, the boats seem to defy the laws of gravity as they bob about on the water above them with their sails pointing down.
The bizarre phenomenon makes for a nifty trick, but researchers say the finding may have practical implications, from mineral processing to separating waste and pollutants from water and other liquids.
Journal Reference:
Vladislav Sorokin, Iliya I. Blekhman. Vibration overcomes gravity on a levitating fluid [open], Nature (DOI: 10.1038/d41586-020-02451-w)
Benjamin Apffel, Filip Novkoski, Antonin Eddi, et al. Floating under a levitating liquid [$], Nature (DOI: 10.1038/s41586-020-2643-8)
(Score: 2) by c0lo on Friday September 04 2020, @03:16AM (5 children)
Now, put a powermeter on the cable to that speaker and get a reading.
Right. Then vibrate that water until all the heavy stuff gets on top, then let the heavy stuff fall and capture the energy.
If you do it properly, you should have super-unity in no time, right?
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 1) by fakefuck39 on Friday September 04 2020, @05:45AM (4 children)
that's not how a wave works. if there's a piece of heavy stuff on top, the wave pushes it up, then the heavy stuff pushes it down as the wave goes down. that wave then goes to the bottom, pushes off the bottom, and comes back on top to push on the heavy stuff. heavy stuff stays on top. no energy is lost.
doing it properly means finding the right wave frequency so the wave makes it down and back up before the heavy stuff starts sinking.
(Score: 2) by c0lo on Friday September 04 2020, @06:08AM (3 children)
Must've been nice in that magic universe of yours.
Unfortunately, in our universe, you get to consume energy to keep the things excited when they would just want to come resting in the lowest potential energy possible.
And, gosh, our universe is so perverse in finding ways to dissipate the energy you put in.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 1) by fakefuck39 on Friday September 04 2020, @04:49PM (2 children)
Yes, there is some heat loss due to the bouncing of a wave. Start a wave in your bathtub and see how long it takes to stop. A long time. That's your tiny energy loss. Magic to you - I know.
(Score: 2) by FatPhil on Friday September 04 2020, @05:27PM (1 child)
Just watch the vid if you're too lazy to read TFA.
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 1) by fakefuck39 on Friday September 04 2020, @07:35PM
You clearly didn't bother to read even my original comment to which you replied. I am not talking about levitating water. I am talking about pushing heavy things up to the top of a large pool of water with waves. You know, like in a bathtub.