Questions tagged [nucleation]
27 questions
7
votes
1 answer
Difference in chemical potential in supersaturated solutions
I have been more or less struggeling to understand an equation that is apparently used in almost all books covering crystals in any way.
Basically every book that I have found explains the following:
In a system with a one-component vapour at the…
phil13131
- 171
6
votes
1 answer
Why do dry lentils cluster around air bubbles?
When I pour dry lentils into a water bowl, I notice many of them form little clusters, with an air bubble in the center.
Why does this happen? I'm guessing something about static electricity. But not sure bubbles or lentils have charge...
Juan Perez
- 3,082
5
votes
1 answer
Bubbling metal vapor through liquid Helium?
When a metal cools from its liquid state, part of the nucleation happens from pre-existing clusters (a group of unit cells of the crystal lattice) already present in the liquid.
In the case of a phase change from vapour directly to solid, on rapid…
Ash
- 196
4
votes
0 answers
Material preventing nucleation, why is it not used for soda container?
I would like to know the answer to the question "why do materials preventing heterogeneous nucleation of $CO_2$ aren't used for soda bottles and glasses?".
Two possible answers so far that I thought about: Either it is too hard to make such a…
3
votes
2 answers
Where do the air bubbles inside the pool come from?
Here's a pic of my legs in the pool water. There are tiny air bubbles on them. I thought this is the result of air coming out of my leg, but I learnt that this is not the case. Also, there seem to be more air bubbles on my left leg than my right…
Abhilash
- 131
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3
votes
1 answer
Explanation of the effect of nucleation sites on various processes
It is common knowledge that water can be cooled and superheated in the absence of nucleation sites. Similarly, the well-known explosion of carbonated drinks due to the dropping of mentos is also explained by nucleation sites causing it.
What is the…
Harsha
- 761
3
votes
1 answer
Why does a bubble arise on an unevenness of a glass?
When you put champaign in a glass, or any other CO2 containing liquid, than often there arise bubble mostly from the same spot.
Bow it is said that the cause for that is that bubbles of CO2 'like to gather' at a tiny unevenness (a sharp point or…
Marijn
- 3,408
2
votes
1 answer
Do superheating and supercooling only occur from liquid?
Superheating of a liquid past its boiling point (retarded boiling) is a well-known phenomenon. However, is there such a thing as supercooling of gas past its condensation point?
Conversely, supercooling of a liquid (retarded freezing) is also…
Nanite
- 3,530
2
votes
1 answer
Why does it take energy to grow the surface of a drop?
Classical nucleation theory predicts that the growth of small nuclei is thermodynamically disfavoured, on account of the energy required to grow its surface. I am struggling to understand why it takes energy to grow a nuclei's surface.
I have done…
Alessandro Power
- 789
2
votes
0 answers
Could some kind of vacuum decay modify the most fundamental laws of physics?
A false vacuum is a hypothetical vacuum that is not actively decaying, but somewhat yet not entirely stable ("metastable"). It may last for a very long time in that state, and might eventually move to a more stable state, an event known as vacuum…
vengaq
- 3,282
2
votes
0 answers
Meaning of *supersaturation* in diffusion cloud chamber
While trying to build a diffusion cloud chamber using the "classical" Langsdorf method, which employs a cold plate to create a steep negative temperature gradient, inducing supersaturation in alcohol vapour, I have found this interesting alternative…
latelrn
- 167
2
votes
1 answer
Determination of the critical homogeneous nucleation radius
Situation
Consider a supercooled liquid. If a spherical solid crystal appears, the variation of the free Gibbs energy is given by
$\Delta G = -\frac{4}{3}\pi\Delta g r^3 + 4\pi\gamma r^2$
where $\Delta g$ is considered the variation of the Gibbs…
joo
- 33
2
votes
2 answers
Why rough surfaces promote nucleation of CO2 in carbonated drinks?
Glassware with scratched/etched surfaces generate more bubbles (video 1, video 2). Why these rough surfaces allow easier heterogeneous nucleation?
Sparkler
- 3,324
1
vote
0 answers
How do I calculate the time required for a super-cooled water droplet undergoing heterogeneous nucleation to complete its phase change?
Consider a super-cooled water droplet impacting a solid substrate. Upon contact, the droplet begins to undergo heterogeneous nucleation. How can one calculate the time required for the droplet to change from liquid to solid, in terms of droplet…
Hilbert Space
- 11
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1
vote
0 answers
Desorption vs reflection (or sticking coefficients) in thermal physical vapor deposition (PVD) of gold
I'm having some issues squaring competing concepts behind the kinetics of adatom deposition in thermal PVD. Mattox (Handbook of Physical Vapor Deposition) repeatedly states Au atoms vaporized via thermal PVD have an approximate energy of 3 eV, of…
ZnPVD
- 11