High Voltage Forum

General Chat => Science, Research and News In Other Fields Than Electronics => Topic started by: haversin on June 15, 2021, 02:27:03 AM

Title: The dramatic difference between wet and dry sphere splashes
Post by: haversin on June 15, 2021, 02:27:03 AM
This phenomenon was first reported by A. M. Worthington in 1882.

Title: Re: The dramatic difference between wet and dry sphere splashes
Post by: haversin on June 16, 2021, 05:40:40 PM
As a follow up, here is a link to a great little paper on the current theory about the sphere splashes:
https://www.nature.com/articles/nphys545.pdf (https://www.nature.com/articles/nphys545.pdf)
Title: Re: The dramatic difference between wet and dry sphere splashes
Post by: davekni on June 16, 2021, 08:00:50 PM
That second paper makes sense.  Are you sure the "wet" and "dry" labels in the first video are correct.  I'd expect the opposite.  I'd expect a wet sphere to behave more hydrophilic and the dry sphere more hydrophobic.
Title: Re: The dramatic difference between wet and dry sphere splashes
Post by: Mads Barnkob on June 16, 2021, 08:54:32 PM
I am not quite following your experiment here.

The paper you reference is talking about chemical processes to make different material spheres more hydrophilic or more hydrophobic, not the difference of a wet and dry sphere. But your experiment is to show that a wet sphere is the same as a chemically treated more hydrophilic sphere?

To improve your high speed video, you should get some 250W of LED lighting, I build one myself from 5x 50W LED COBs ( https://kaizerpowerelectronics.dk/general-electronics/250w-led-flood-light/ ), that I use for high speed video recording :) I could try to replicate your experiment with some more details on all the parts of your experiment. Its a little thin to just drop a video with no explanations...
Title: Re: The dramatic difference between wet and dry sphere splashes
Post by: haversin on June 17, 2021, 02:49:00 AM
That second paper makes sense.  Are you sure the "wet" and "dry" labels in the first video are correct.

The labels are correct. I got the same results as A. M. Worthington. He talks about it here:
https://www.gutenberg.org/files/39831/39831-h/39831-h.htm#Page_73 (https://www.gutenberg.org/files/39831/39831-h/39831-h.htm#Page_73)

The paper you reference is talking about chemical processes to make different material spheres more hydrophilic or more hydrophobic, not the difference of a wet and dry sphere. But your experiment is to show that a wet sphere is the same as a chemically treated more hydrophilic sphere?
I was first trying to replicate A. M. Worthington's observation.

To improve your high speed video, you should get some 250W of LED lighting

The camera I'm using only gets 224 x 64 pixels at 1000 frames per second. I don't think more light will help much!  :-\

I could try to replicate your experiment with some more details on all the parts of your experiment. Its a little thin to just drop a video with no explanations...

I thought I explained my setup pretty well, what part don't you understand?
Title: Re: The dramatic difference between wet and dry sphere splashes
Post by: Mads Barnkob on June 17, 2021, 12:42:03 PM
I understand it now, it was just the missing link between your experiment being a replica of the subsequent experiment as A.M.Worthington describes as

Quote
"By wetting the surface of a smooth sphere we can always convert a smooth or "sheath" splash into a rough or "basket" splash. Thus when the ivory sphere (which when dry and well-polished gave, with a fall of 60 cm., the splash of Series XI, p. 97), was allowed to fall wet into the liquid, all other circumstances remaining the same, the splash of Series XIII, p. 103, was obtained, which is entirely different from the first. The wetting was effected by dipping the sphere into the bowl of milky water into which it was to fall, and then shaking off as much as possible of the adherent liquid, but in all cases the splash quickly became unsymmetrical, probably through the liquid, during the fall, drifting to one side of the sphere."

Just as Dave, I thought you replicated the hydrophilic/hydrophobic experiment, because from not knowing the papers beforehand, its counterintuitive that a wet sphere is going to act hydrophobic :)
SimplePortal 2.3.6 © 2008-2014, SimplePortal