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There are some animals that use Capillary Action, such as the M.horridus, yet I see no mention of this here. Please add this so you can complete the article. Meapyeah ( talk) 16:58, 7 May 2014 (UTC)
glass to a pool of blood on the fingertip after a prick. How does it work though? That's what I came here to find out, and I had to make the entry myself! I don't know, but I wonder if it has something to do with surface tension. Maybe the water molecules are attracted to the sides of the capillary tube. Successive H20 molecules leapfrog eachother up the sides of the tube. Each higher molecule is happy to have found some tube wall it can call it's own. Then surface tension brings up the column a bit more, then another molecule finds the wall a bit higher and so on? It seems like quite a thermodynamics problem though: What is providing the power to lift the column of water? Where is that energy coming from?"
The above text was cut and pasted from the article page. So far the questions raised by the above user have not all been addressed on the article Theresa knott 14:18 May 13, 2003 (UTC)
Is capillary action the same thing as Capillarity? And if so, should they be merged? -- liquidGhoul 06:59, 16 June 2006 (UTC)
I thought that capillary action occurred with or without gravity, so shouldn't the definition on the top of the page be changed? 66.189.116.168 19:55, 4 September 2006 (UTC) John S.
moved this tage here - because the page has been idle for ages, and this tag is ugly!....
{{ unreferenced}}
cheers, Petesmiles 00:13, 29 December 2006 (UTC)
According to this site the contact angle does not matter in determining the height that the water will climb a tube.
http://www.wtamu.edu/~crobinson/SoilWater/capillar.html
This is confirmed on this site which also has derivation of the height formula. This comes from the formula for the adhesion force and the formula for the gravitational force.
http://hyperphysics.phy-astr.gsu.edu/hbase/surten2.html
66.150.98.244 06:17, 2 April 2007 (UTC)
Can someone please double check the formula and the values used for the equation? There is an error in there. I was able to derive the 1.4 * 10^-5 from the values provided. But, if this part is true, the height of the column of water would be about 14 cm for a 0.1 mm diameter tube and about 7 cm for a .2 mm tube. So, either one of the numbers supplied are incorrect, or the results are incorrect.
-- Jlinde 17:09, 10 November 2007 (UTC)
Regarding the temperature changes of the surface tension, the article states the formula is gamma*V^2/3=k(Tc-T-6), meaning surface tension would be gamma = k(Tc-T-6)/(V^2/3). As stated: k=2.1*10^-7 J/K/mol^(2/3) Tc=374°C T=20°C thus surface tension = 1.06*10^-5 Can somebody confirm this or am I doing something wrong in the calculation? 83.119.136.130 ( talk) 13:47, 27 June 2010 (UTC)
In response to the box at the top of the page.
"A common misconception is that water moves in xylem by capillary action—the movement of water along a small-diameter conduit (such as a capillary) as a result of surface tension in the meniscus at the leading surface of the moving water. Surface tension does play a critical role in water movement in xylem, as described above, but the relevant force acts at the surface site of evaporation within leaves, not within the xylem conduits. Water movement within the xylem conduits is driven by a pressure gradient created by such force, not by capillary action." - Transpirational pull
So I am not sure that such discussion would be applicable to this section. 66.150.98.244 06:53, 2 April 2007 (UTC)
Hi ,
I'm a french wikipedian humble contributor. I'm looking for a confirmation : The formula presented in the main text of this article, is the Jurin or the Laplace's law ? In my opinion, James Jurin was the first to express it like that in 1718 (if I'm right)... But I already see the term Laplace's law in scientific litterature... Laplace made this job with soap bubbles, isn't it ? Is there someone to give me an definitve answer ?
Thank's in advance, Dam s.vador 12:42, 18 June 2007 (UTC)
This article does not make it sufficienty clear that the phenomenon occurs in two related but different situations:
Read the surface tension article and realise that we are not worthy. I will try to have a go at cleanup some time. Cutler 15:28, 5 September 2007 (UTC)
In the formula for height, h=2TcosØ/dgr where, t=surface tension Ø=angle of contact d=density g=grav. acceleration r=radius of capillary REFER SURFACE TENSION
116.72.26.239 ( talk) 18:02, 12 June 2010 (UTC)NIK
The article is using surface tension in a slightly confusing way. First we are told that capillary action ".. occurs because of inter-molecular attractive forces between the liquid and solid surrounding surface ..", but then "Surface tension pulls the liquid column up ..". I get the impression that the second sentence refers to the air-liquid interface, which cannot be correct. This can be easily seen from the figures of the capillaries, the surface between the liquid and the air is exactly the same no matter how high the liquid rises, so there is no way that this can be the cause of capillary action. The formula of the capillary height is also 'misleading' in this way. The liquid-air surface tension enters as a constant, and gives the impression that the effect happens at the liquid-air interface. I guess that this constant multiplied by the cosine of the contact angle tells us something about the liquid-solid interaction, which is the important parameter. In this sense there is nothing incorrect in the article, but a non-expert will get the impression that capillary action is caused by the water(-air) surface inside the capillary. Perhaps surface tension is not a useful concept in this article? -- 130.226.87.164 ( talk) 19:43, 14 February 2011 (UTC)
I made the calculation for water less approximate and tried but failed to correct the dimension from meter to the correct meter^2 I've not yet learned to use the math functions. — Preceding unsigned comment added by Zedshort ( talk • contribs) 22:26, 19 January 2012 (UTC)
The following statement about the etymology of the term was unreferenced and sounds like guesswork:
I have no source either, but the term "capillary" for glass tubes and for the blood vessels surely is only a Latinate way of saying "hair thin". I don't remember which one I heard first, "capillary tube" or "capillary action", but they usually go together, so it seems at least plausible that the action was named by physicists after the tube (because it is most dramatic in such tubes).
Anyway, the etymology should be backed by a reliable source. --
Jorge Stolfi (
talk) 04:02, 25 February 2013 (UTC)
I had been taught that soldering relies on capillary action - that the molten solder metal flows into the narrow space between the heated metal components to be joined.
If this is the case, then the mechanism cannot be based on hydrogen-bond attraction. I came to this article to try to find out about this, yet here, the only examples given are of aqueous liquids and polar solids (the mercury in the diagram is used to illustrate capillarity action _not_ happening).
So, is flow of molten metal during soldering a capillary phenomenon, or not? If it is, there should be some mention of it, and the molecular/atomic mechanism; if not, then a note to say that it's a different thing.
Thanks very much if someone can clarify this point in this article. 120.18.205.32 ( talk) 01:20, 3 April 2013 (UTC)
This article explains "wiking" but hardly, and has many details about meniscus but nothing about pressure and area, air pressure, and why this makes a difference.
That being so, it says a long "capillary straw", placed vertically especially between areas of differing pressure, that the pumping of fluid against gravity operates purely on meniscus: and that then capillary is merely a pseudonym for meniscus. That's not what i've heard.
However my remark is: I don't know what your reading from what decade: but the definitions were not (are not thank you) the same.
in addition to the comment above. The main article states (despite contradition in MANY SOURCES) that "down" meniscus of Hg is the driving force behind thermometors. I've heard but will not cite that the expansion rage of Hg due to temperature might be involved, as is STP (pressure and temperature standards) in building one.
I'm finding allot of wiki articles with contributions deleted which maddenly describe everything except why one would likely read the article. And i think it is from competing gov workers who are making "for pay" encyclopedias and almanacs using tax money, just a guess.
And wait a minute Hg thermometer: even wikipedia Mercury-in-glass_thermometer doesn't mention meniscus. I take back my comment about "there being many sources" and cite that.
And I never was a fan of "continuum math" texts, they are "too new" for me, redefine things already defined and sometimes confusingly, and appear contrived. — Preceding unsigned comment added by 72.219.202.186 ( talk) 19:12, 10 September 2014 (UTC)
I love material science and that subsection, but the absorption of moisture by cinder blocks is not necessarily completley defined as capillarly - and probably doesn't belong in the article.
Intermolecular attraction "in general" should not be used as meaning "capillary"
For example: capillar and cavity: not the same word or definition
Now as to porosity, it is possible for moisture to be attracted ionically, due to lack of moisture of the material. Hydroscopic is a topic.
This obviously arrives at: the fact of dryness (below standard moisture at STP) and porosity allowing moisture to permeate within - is not capillary necessarily - or in general. Saying so would then define all chemical reacations as capillary: which is just more and more far afield from the definition.
Capillary \Cap"il*la*ry\, n.; pl. {Capillaries}. 1. A tube or vessel, extremely fine or minute. [1913 Webster]
more: caput (head) capilla (hair), captus (capturing, taking), capis (vessel). and these were used to describe things figuratively. (of latin/greek family origins)
It's frustrating to have words re-defined so that they no longer have individual meaning: it makes it impossible for those who wish a vocabulary with differentiation. (new webster's is awful with this, giving the same definitions for many words to all mean the same - which used to be different so as to convery different ideas)
Obviously what i mean is: capillary implies tubes, not porosity. defining the two as the same simply destroys the language. saying meniscus is capillary are the same is a next intrusion of common sense.
The comment(s) below were originally left at Talk:Capillary action/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.
Rated "top" as high school/SAT biology content and important biophysical concept, e.g. water conduction in plant cells. The article could need some expansion with biological examples and context. - tameeria 05:10, 19 February 2007 (UTC) |
Last edited at 05:10, 19 February 2007 (UTC). Substituted at 10:50, 29 April 2016 (UTC)
The first figure, with caption "Capillary action of water compared to mercury, ..." is vague and looks to be wrong.
I think this was intended to illustrate 1: the difference in meniscus shape between water and mercury 2: narrower capillary tube produces more effect
It would help if the caption made this clear.
Further, and more serious, in the water section's five columns of water, the 2nd is (slightly) wider than the 3rd, yet has a higher meniscus. This appears to be wrong. Gwideman ( talk) 18:31, 16 September 2019 (UTC)
How is Hooke not mentioned even once in the entire page about capillary action? He published the first scientific pamphlet about the phenomenon in april 1661...
Missentropi ( talk) 18:28, 4 October 2019 (UTC)
Given that, as the article correctly says, transpiration is not in fact driven primarily by capillary action, why is there an in-depth discussion of it on this page at all, let alone it being one of the first sections? Droideka30 ( talk) 20:09, 17 September 2022 (UTC)