Forwarded to Vortex on behalf of Michel who seems unable to get through. ------------------------------------------------------------------------------
On Tue, 12 Jun 2007 10:36:57 +0200, "Michel Jullian" <[EMAIL PROTECTED]> wrote: >To: <vortex-l@eskimo.com> >Subject: Re: [Vo]:Goose bumps at the surface of a polarized liquid submitted >to a field >From: "Michel Jullian" <[EMAIL PROTECTED]> >Date: Mon, 11 Jun 2007 10:08:24 +0200 > > >Bill wrote: >... >>> http://www.youtube.com/watch?v=zpBxCnHU8Ao >>> Beautiful video. The bumps at the beginning (threshold field presumably) >>> may be relevant to your airthreads phenomenon. >> >> Such bumps are known to arise with distilled de-ionized (DI) water. But >> for tap water, there is no molecular alignment because the e-fields within >> the water are zero when opposite ions are attracted to the surface, >> serving as a conductive shield. > >Good point, tap water is conductive so it can't be the same phenomenon. > >... >> I've played with a large quantity of ferrofluid. The "spines" are very >> similar to the spines seen when a magnet picks up quantities of iron >> powder. > >Yes, only more fluid-looking as would be expected. > >> One huge blob of iron powder is unstable, and instead the blob >> breaks into two spines which repel each other, then those break up as >> well, ideally forming an array. (Oddly enough, ferrofluid forms square >> arrays of spines, rather than hexagonal close-packing.) >> >>> Wrt the hollow you unambiguously observed by laser >>> reflection, might it have been a "valley" between several bumps or the >>> inside of a volcano-like structure? >> >> I guess I wasn't clear enough. When a relatively huge flow of "electric >> wind" blows from a metal needle, it blasts a huge hole in the mist layer >> (many cm diameter) with lots of easily observed turbulent stirring of the >> fog. And at the >> same time, it pushes a valley into the water. This is not the "air >> threads" or filaments I observed. Instead it's a high-current phenomenon >> on the scale of microamps or hundreds of nanoamps. It only appears when >> a metal needle is held appx 10cm from the water surface. >> >> The "air threads" or fibers which create mm-wide holes in the fog... those >> don't create any easily-detected changes in the water surface. These >> "threads" are created by holding a sharp, high-resistance non-metal object >> appx 30cm from the water surface. I used carbon fibers, torn paper edges, >> and human hairs (especially eyelashes) to create the thread-like >> phenomena. I only conducted a brief test when looking for water surface >> deflections. Perhaps an experiment more carefully performed than my own >> will detect a pimple or a valley. > >OK I get it, thanks for clarifying the differences. > >About the low current phenomenon, it occurs to me that a sufficiently low >current ion stream, where the ions would form a clearly discrete dotted line >rather than a continuous-looking stream, would not expand sideways by self >repulsion as we have been assuming all along. Each ion would just follow the >previous one at comfortable distance, only sigzaging slightly along the line >of maximum field while it collides with neutrals every micron or so. Could >this reconcile the ion wind theory with your observations? > >Michel Regards, Robin van Spaandonk The shrub is a plant.
