The liquid that pours itself - Polyethylene Oxide


#1

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#2

Liquid helium will do that without encouragement. It’s kind of creepy.


#3

Oh, I have that at my house, we call it Whiskey.


#4

“One of the slimiest substances known to man”

Crap, so that’s what the Republican Party hands out for hair gel!


#5

Also used in heavy-duty lubes for veterinary obstetrics. Or so they say, I am sure that I wouldn’t know!


#6

So it sort of syphons itself?


#7

You might think it’s polyethylene oxide, but it’s snot.


#8

I see what you did there


#9

Huh, I have a jar of that stuff in my freezer. In powdered form. You can buy some easily online. Oddly, when I asked Dow Chemicals for a sample, they said something along the lines of “not a target market” or something.

The reason I got some is to make giant soap bubble fluid, following some recipes online. A teensy-tiny amount of Poly-Ox will help the giant bubble keep its integrity and even recover from tears. And by teensy-tiny, I mean <1g for the concentrated bubble liquid.

For the soap bubbles, you actually can’t put the dab of powder you’re using directly into water, because the powder will form a casing of gel preventing the rest of the powder from dissolving! I had to dilute it in ethanol first, as recommended.

It’s impressive how powerful the powder is: for the amount of “snot” in Steve’s video, I suspect he used 1-5g of the powder. Just a pinch.

And I have 1/5lb of it to go through…


#10

One small amount of a slimy substance wants to leave, and it drags everything else with it. This is Brexit again, isn’t it?


#11

IIRC, liquid helium does that because the atmospheric pressure pushes down on it, causing it to flow out of the container? (Like when you put you hand in a container full of water)


#12

Yes, just search Amazon for ‘anal fisting powder’.


#13

This just begs for a catchy tune. Specifically one by Bert Bacharach…


#14

No, it does that because it is a superfluid. You can think of it as something like a Bose-Einstein condensate. Being bosons, all the atoms want to be in the same quantum state. There is a skin effect similar to surface tension that wets up the side of the container and that’s all you need for other atoms to want to be in the same state as those atoms are. Up the go. Being a superfluid, the viscosity is zero so they can keep creeping spontaneously up the side of the container and over the top.


#15

so it’s a smaller version of this:


#16

Um, no. Which then leaves me the much harder job of explaining what it actually does.

Oh dear. Without the maths, this won’t make a lot of sense, but here goes…

If you look at liquid helium, it looks like butane inside a disposable lighter. I used to have a dewar like this for my PhD, and I could look at the helium level. The liquid you see has two components that occupy the same space. One part is discrete atoms, which is a liquid with low viscosity; and the other part is a Bose-Einstein condensate, where all the atoms can be described by a single wave function, and this has no classical viscosity at all. And other occupy the same space. This can flow through tiny hole where ordinary atoms can’t. It can also climb surfaces, and syphon itself.

This is a bit like electrons in a superconductor: some of them are ordinary metal conduction band electrons, while others go to this single wave function which is so large that ordinary things that scatter electrons do not scatter the superelectron wave function, so they can conduct a steady DC current in a loop forever. In liquid helium, you can get vortices that flow forever too.

That still does’t make that much sense. OK, think of lots of people going down the street, and you want to go the other way. You can only see one or two people ahead, and you are always bumping or just missing people. Now suppose you have a lot of soldiers marching in ranks. They can sense disturbances in the ranks many rows ahead from small changes in the relative position of the person ahead, so they effectively sense what is going on ten ranks in from or behind, and they can flow around you in formation without breaking step. Getting in ranks is like ordering process like crystallisation, and it can be destroyed by too much disturbance (heating), but it can take flow around a small amount of disturbance without loss. Now, this isn’t a wonderful analogy as electrons and helium atoms do not go in straight rows; but helium atoms and electrons at low temperatures can go to some common lowest-energy alignment where the individual wave functions overlap with tens or hundreds of other wave functions in each direction, so the combined wavefunction can flow past obstacles that would scatter and cause viscosity or resistance in ordinary liquids and conduction band electrons.

Hope this helped a bit.


#17

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