
Why gas bubbles appear to get stuck inside narrow vertical tubes - ekoutanov
https://www.livescience.com/why-gas-bubbles-stuck-vertical-tubes.html
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woah
I thought it was common sense that the bubble gets stuck because the liquid
needs to flow down for the bubble to go up. The bubble’s pressure pushes the
liquid against the wall so that it can flow down only very slowly. Surface
tension stops the liquid from breaking the bubble and flowing down the center.

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tsbinz
"But in this case, the researchers used a custom-made microscope that shines a
light onto the sample and measures the intensity of the light that bounces
back."

That's how eyes work as well. Well, they need a light source to help, but
otherwise ...

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mattkrause
Not always how a microscope works though.

This article has a nice little comparison of a few different methods, not all
of which measure (only) reflection [https://en.wikipedia.org/wiki/Dark-
field_microscopy](https://en.wikipedia.org/wiki/Dark-field_microscopy)

There’s also a whole world of microscopy where emissions from the sample
itself are measured, often because parts of it have been tagged with
fluorescent probes.

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anotheryou
You can even see it sometimes, bubble stuck, draining around it slowly. Really
no surprise to me...

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xchip
TL;DR:

"Some calculations suggested that the bubble is surrounded by an extremely
thin layer of liquid touching the sides of the tube, which slowly diminishes
in size and eventually disappears, Kolinski said. That thin layer would create
resistance to the motion of the bubble as it tries to rise."

~~~
abstractbeliefs
But actually they disproved this belief:

'The researchers indeed observed this very thin layer around the gas bubble
and measured it to be about 1 nanometer thick. That's what quenches the
movement of the bubble as theoretical work had predicted. But they also found
that the liquid layer (which forms because the pressure in the gas bubble
pushes against the walls of the tube) doesn't disappear, but rather stays at a
constant thickness at all times.

Based on their measurements of the thin layer of fluid, they were also able to
calculate its velocity. They found that the gas bubble isn't stuck at all but
is rather moving "extraordinarily slowly," at a pace invisible to the naked
eye'

~~~
londons_explore
There is also evaporation occurring on the top surface of the gas bubble, and
condensation happening on the bottom.

Since there is a small pressure differential, there will be a net upwards
movement.

It's a small effect, but it might dominate.

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HocusLocus
bubble stuck

please send help

