Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > sci.physics > #505715 > unrolled thread

Why do puddles stop spreading? Simple everyday phenomenon was unexplained by physics—until now

Back to article view | Back to sci.physics

Contents

  Why do puddles stop spreading? Simple everyday phenomenon was unexplained by physics—until now Sam Wormley <swormley1@gmail.com> - 2015-07-08 19:02 -0500
    Re: Why do puddles stop spreading? Simple everyday phenomenon was unexplained by physics—until now jimp@specsol.spam.sux.com - 2015-07-09 00:35 +0000
    Re: Why do puddles stop spreading? Simple everyday phenomenon was unexplained by physics—until now Simoen <invalid@invalid.com> - 2015-07-09 22:25 -0500
    Re: Why do puddles stop spreading? Simple everyday phenomenon was unexplained by physics—until now Wally W. <ww84wa@aim.com> - 2015-07-09 23:33 -0400
    Re: Why do puddles stop spreading? Simple everyday phenomenon was unexplained by physics--until now "hanson" <hanson@quick.net> - 2015-07-10 13:53 -0700

#505715 — Why do puddles stop spreading? Simple everyday phenomenon was unexplained by physics—until now

Why do puddles stop spreading? Simple everyday phenomenon was 
unexplained by physics—until now
> http://phys.org/news/2015-07-puddles-simple-everyday-phenomenon-unexplained.html

> When you spill a bit of water onto a tabletop, the puddle spreads—and
> then stops, leaving a well-defined area of water with a sharp
> boundary.

> There's just one problem: The formulas scientists use to describe
> such a fluid flow say that the water should just keep spreading
> endlessly. Everyone knows that's not the case—but why?

> This mystery has now been solved by researchers at MIT—and while this
> phenomenon might seem trivial, the finding's ramifications could be
> significant: Understanding such flowing fluids is essential for
> processes from the lubrication of gears and machinery to the
> potential sequestration of carbon dioxide emissions in porous
> underground formations.

> The new findings are reported in the journal Physical Review Letters
> in a paper by Ruben Juanes, an associate professor of civil and
> environmental engineering, graduate student Amir Pahlavan, research
> associate Luis Cueto-Felgueroso, and mechanical engineering professor
> Gareth McKinley.

> "The classic thin-film model describes the spreading of a liquid
> film, but it doesn't predict it stopping," Pahlavan says. It turns
> out that the problem is one of scale, he says: It's only at the
> molecular level that the forces responsible for stopping the flow
> begin to show up. And even though these forces are minuscule, their
> effect changes how the liquid behaves in a way that is obvious at a
> much larger scale.

> "Within a macroscopic view of this problem, there's nothing that
> stops the puddle from spreading. There's something missing here,"
> Pahlavan says.

> Classical descriptions of spreading have a number of inconsistencies:
> For example, they require an infinite force to get a puddle to start
> spreading. But close to a puddle's edge, "the liquid-solid and
> liquid-air interfaces start feeling each other," Pahlavan says.
> "These are the missing intermolecular forces in the macroscopic
> description." Properly accounting for these forces resolves the
> previous paradoxes, he says.

> "What's striking here," Pahlavan adds, is that "what's actually
> stopping the puddle is forces that only act at the nanoscale." This
> illustrates very nicely how nanoscale physics affect our daily
> experiences, he says.


-- 

sci.physics is an unmoderated newsgroup dedicated to the discussion
of physics, news from the physics community, and physics-related
social issues.

[toc] | [next] | [standalone]

#505720

Sam Wormley <swormley1@gmail.com> wrote:
> Why do puddles stop spreading? Simple everyday phenomenon was 
> unexplained by physics?until now
>> http://phys.org/news/2015-07-puddles-simple-everyday-phenomenon-unexplained.html
> 
>> When you spill a bit of water onto a tabletop, the puddle spreads?and
>> then stops, leaving a well-defined area of water with a sharp
>> boundary.
> 
>> There's just one problem: The formulas scientists use to describe
>> such a fluid flow say that the water should just keep spreading
>> endlessly. Everyone knows that's not the case?but why?

Because some idiot is using the wrong formulas.


-- 
Jim Pennino

[toc] | [prev] | [next] | [standalone]

#506029

On 7/8/2015 7:02 PM, Sam Wormley wrote:
> Why do puddles stop spreading? Simple everyday phenomenon was

>> When you spill a bit of water onto a tabletop, the puddle spreads—and
>> then stops, leaving a well-defined area of water with a sharp
>> boundary.

>> There's just one problem: The formulas scientists use to describe
>> such a fluid flow say that the water should just keep spreading
>> endlessly. Everyone knows that's not the case—but why?

you have the wrong dumbass scientists.


-another zinger by the Fat Ass in a Cube Making Stuff Up @phys.org

[toc] | [prev] | [next] | [standalone]

#506031 — Re: Why do puddles stop spreading? Simple everyday phenomenon was unexplained by physics—until now

On Wed, 8 Jul 2015 19:02:41 -0500, Sam Wormley wrote:

>> "Within a macroscopic view of this problem, there's nothing that
>> stops the puddle from spreading. There's something missing here,"
>> Pahlavan says.

Conservation of mass.

mass = density * area * depth.

Can the depth be less than one molecule thick?

"there's nothing that stops the puddle from spreading"?!

This came from MIT?!

Also see: adhesion, cohesion, surface tension.

Duh!

[toc] | [prev] | [next] | [standalone]

#506181 — Re: Why do puddles stop spreading? Simple everyday phenomenon was unexplained by physics--until now

<herbertglazier0@gmail.com> Glazier the Swine "reber g=emc^2" 
produced the following Glazierola and wrote:
I blew their minds when I showed them my fast pictures.
My method I improved on and is now twist as fast. 
Nobel stuff indeed. TreBert Also shown at U of Mass 
and U of Irvine (but Dr. Peter has not responded) & E&GG 
in Wellsley Ma who build the Edgington strobe light.  TreBert
>
hanson wrote:
Glazier you narcissistic Swine, what else did you
blow besides their minds? Sheesh!... Listen up,
Glazier, you Face shitter & Graveyard vandal: So
you went to all those places, lied and tried to 
con them, but how much money did you make?
"I will make a post on that. O ya. It's right on the money"

[toc] | [prev] | [standalone]

Back to top | Article view | sci.physics

csiph-web