Re: [Phys-l] tiny bubbles

[Bernard Cleyet <bernardcleyet@redshift.com>]

How's this:  the sky is blu, for the same reason * there are nucleation 
sites, admittedly very small. 

*  no liquid has uniform density (except a Bose condensate?)

bc


Stefan Jeglinski wrote:  [back in Feb.]

> > Ionizing rays, entering the vessel would play a role. But your ideal
> > world probably does not have such rays.
> >    
>
> Fair enough. To be more clear, I'm trying to figure if the ultimate
> "force" in this matter is still nucleation sites. Or does something
> else substitute for such sites? An argument that uneven heating could
> create density gradients that in effect were equivalent to a
> nucleation site, seems plausible. Or your ionizing rays creating
> highly localized conditions that are essentially... nucleation sites?
>
> Bill Beaty's page (referenced in another post) dodged the most
> important question, when he said "since its temperature has risen so
> high above 100C that bubbles are appearing spontaneously". OK, what's
> causing the bubbles to appear *spontaneously*? Is it merely a
> smaller-scale nucleation site such as a microscopic steam bubble? If
> so, how does said steam bubble occur? As a result of even smaller
> nucleation sites?
>
> Perhaps on any scale, one can observe *something* that can be
> considered a nucleation site. I have no problem with that - I'm just
> curious to know if eventually there is a departure from this
> mechanism, or if it's nucleation sites all the way down, as it were.
>
> I quite suspect reality keeps this from being answered experimentally
> without great difficulty. I think I once ran across
> discussion/publication of the highest temperatures ever achieved,
> after careful preparation, for superheated water, but I don't recall
> the result.
>
>
> Stefan Jeglinski
>
>
>