2 Phenomena and physics of capillary action
3 In plants and animals
5 Height of a meniscus
The first recorded observation of capillary action was by Leonardo da
Vinci. A former student of Galileo, Niccolò Aggiunti (it),
was said to have investigated capillary action. In 1660, capillary
action was still a novelty to the Irish chemist Robert Boyle, when he
reported that "some inquisitive French Men" had observed that when a
capillary tube was dipped into water, the water would ascend to "some
height in the Pipe". Boyle then reported an experiment in which he
dipped a capillary tube into red wine and then subjected the tube to a
partial vacuum. He found that the vacuum had no observable influence
on the height of the liquid in the capillary, so the behavior of
liquids in capillary tubes was due to some phenomenon different from
that which governed mercury barometers.
Others soon followed Boyle's lead. Some (e.g., Honoré Fabri,
Jacob Bernoulli) thought that liquids rose in capillaries because
air could not enter capillaries as easily as liquids, so the air
pressure was lower inside capillaries. Others (e.g., Isaac Vossius,
Giovanni Alfonso Borelli, Louis Carré, Francis Hauksbee,
Josia Weitbrecht) thought that the particles of liquid were
attracted to each other and to the walls of the capillary.
Although experimental studies continued during the 18th century, a
successful quantitative treatment of capillary action was not
attained until 1805 by two investigators: Thomas Young of the United
Capillary flow experiment to investigate capillary flows and phenomena aboard the International Space Station
A common apparatus used to demonstrate the phenomenon is the capillary
tube. When the lower end of a vertical glass tube is placed in a
liquid, such as water, a concave meniscus forms.
displaystyle Psi _ m
) drive capillary action in soil. Height of a meniscus
The height h of a liquid column is given by
2 γ cos
ρ g r
displaystyle h= 2gamma cos theta over rho gr ,
displaystyle scriptstyle gamma
is the liquid-air surface tension (force/unit length), θ is the contact angle, ρ is the density of liquid (mass/volume), g is the local acceleration due to gravity (length/square of time), and r is the radius of tube. Thus the thinner the space in which the water can travel, the further up it goes. For a water-filled glass tube in air at standard laboratory conditions, γ = 0.0728 N/m at 20 °C, ρ = 1000 kg/m3, and g = 9.81 m/s2. For these values, the height of the water column is
displaystyle happrox 1.48times 10^ -5 over r mbox m .
Thus for a 2 m (6.6 ft) radius glass tube in lab conditions
given above, the water would rise an unnoticeable 0.007 mm
(0.00028 in). However, for a 2 cm (0.79 in) radius
tube, the water would rise 0.7 mm (0.028 in), and for a
0.2 mm (0.0079 in) radius tube, the water would rise
70 mm (2.8 in).
Capillary flow in a brick, with a sorptivity of 5.0 mm·min−1/2 and a porosity of 0.25.
When a dry porous medium, such as a brick or a wick, is brought into contact with a liquid, it will start absorbing the liquid at a rate which decreases over time. When considering evaporation, liquid penetration will reach a limit dependent on parameters of temperature, humidity and permeability. For a bar of material with cross-sectional area A that is wetted on one end, the cumulative volume V of absorbed liquid after a time t is
V = A S
displaystyle V=AS sqrt t ,
where S is the sorptivity of the medium, in units of m·s−1/2 or mm·min−1/2. This time dependence relation is similar to Washburn's equation for the wicking in capillaries and capillary media. The quantity
displaystyle i= frac V A
is called the cumulative liquid intake, with the dimension of length. The wetted length of the bar, that is the distance between the wetted end of the bar and the so-called wet front, is dependent on the fraction f of the volume occupied by voids. This number f is the porosity of the medium; the wetted length is then
displaystyle x= frac i f = frac S f sqrt t .
Some authors use the quantity S/f as the sorptivity. The above description is for the case where gravity and evaporation do not play a role. Sorptivity is a relevant property of building materials, because it affects the amount of rising dampness. Some values for the sorptivity of building materials are in the table below.
Material Sorptivity (mm·min−1/2) Source
Aerated concrete 0.50 
Gypsum plaster 3.50 
Clay brick 1.16 
Mortar 0.70 
Concrete brick 0.20 
Bound water Capillary fringe Capillary pressure Capillary wave Capillary bridges Damp-proof course Frost flowers Frost heaving Hindu milk miracle Krogh model Needle ice Surface tension Washburn's equation Water Wick effect Young–Laplace equation
^ "Capillary Action – Liquid, Water, Force, and Surface – JRank Articles". Science.jrank.org. Archived from the original on 2013-05-27. Retrieved 2013-06-18. ^ See:
Manuscripts of Léonardo de Vinci (Paris), vol. N, folios 11, 67, and
Guillaume Libri, Histoire des sciences mathématiques en Italie,
depuis la Renaissance des lettres jusqu'a la fin du dix-septième
siecle [History of the mathematical sciences in Italy, from the
Renaissance until the end of the seventeenth century] (Paris, France:
Jules Renouard et cie., 1840), vol. 3, page 54 Archived 2016-12-24 at
the Wayback Machine.. From page 54: "Enfin, deux observations
capitales, celle de l'action capillaire (7) et celle de la diffraction
(8), dont jusqu'à présent on avait méconnu le véritable auteur,
sont dues également à ce brillant génie." (Finally, two
major observations, that of capillary action (7) and that of
diffraction (8), the true author of which until now had not been
recognized, are also due to this brilliant genius.)
C. Wolf (1857) "Vom Einfluss der Temperatur auf die Erscheinungen in
Haarröhrchen" (On the influence of temperature on phenomena in
Annalen der Physik und Chemie, 101 (177) :
550–576 ; see footnote on page 551 Archived 2014-06-29 at the
Wayback Machine. by editor Johann C. Poggendorff. From page 551: " ...
nach Libri (Hist. des sciences math. en Italie, T. III, p. 54) in den
zu Paris aufbewahrten Handschriften des grossen Künstlers Leonardo da
Vinci (gestorben 1519) schon Beobachtungen dieser Art vorfinden; ... "
( ... according to Libri (History of the mathematical sciences in
Italy, vol. 3, p. 54) observations of this kind [i.e., of capillary
action] are already to be found in the manuscripts of the great artist
Leonardo da Vinci
^ More detailed histories of research on capillary action can be found in:
David Brewster, ed., Edinburgh Encyclopaedia (Philadelphia, Pennsylvania: Joseph and Edward Parker, 1832), volume 10, pp. 805–823 Archived 2016-12-24 at the Wayback Machine.. Maxwell, James Clerk; Strutt, John William (1911). "Capillary Action". In Chisholm, Hugh. Encyclopædia Britannica. 5 (11th ed.). Cambridge University Press. pp. 256–275. John Uri Lloyd (1902) "References to capillarity to the end of the year 1900," Archived 2014-12-14 at the Wayback Machine. Bulletin of the Lloyd Library and Museum of Botany, Pharmacy and Materia Medica, 1 (4) : 99–204.
^ In his book of 1759, Giovani Batista Clemente Nelli (1725–1793) stated (p. 87) that he had "un libro di problem vari geometrici ec. e di speculazioni, ed esperienze fisiche ec." (a book of various geometric problems and of speculation and physical experiments, etc.) by Aggiunti. On pages 91–92, he quotes from this book: Aggiunti attributed capillary action to "moto occulto" (hidden/secret motion). He proposed that mosquitoes, butterflies, and bees feed via capillary action, and that sap ascends in plants via capillary action. See: Giovambatista Clemente Nelli, Saggio di Storia Letteraria Fiorentina del Secolo XVII ... [Essay on Florence's literary history in the 17th century, ... ] (Lucca, (Italy): Vincenzo Giuntini, 1759), pp. 91–92. Archived 2014-07-27 at the Wayback Machine. ^ Robert Boyle, New Experiments Physico-Mechanical touching the Spring of the Air, ... (Oxford, England: H. Hall, 1660), pp. 265–270. Available on-line at: Echo (Max Planck Institute for the History of Science; Berlin, Germany) Archived 2014-03-05 at the Wayback Machine.. ^ See, for example:
Honorato Fabri, Dialogi physici ... ((Lyon (Lugdunum), France: 1665), pages 157 ff Archived 2016-12-24 at the Wayback Machine. "Dialogus Quartus. In quo, de libratis suspensisque liquoribus & Mercurio disputatur. (Dialogue four. In which the balance and suspension of liquids and mercury is discussed). Honorato Fabri, Dialogi physici ... ((Lyon (Lugdunum), France: Antoine Molin, 1669), pages 267 ff Archived 2017-04-07 at the Wayback Machine. "Alithophilus, Dialogus quartus, in quo nonnulla discutiuntur à D. Montanario opposita circa elevationem Humoris in canaliculis, etc." (Alithophilus, Fourth dialogue, in which Dr. Montanari's opposition regarding the elevation of liquids in capillaries is utterly refuted).
^ Jacob Bernoulli, Dissertatio de Gravitate Ætheris Archived 2017-04-07 at the Wayback Machine. (Amsterdam, Netherlands: Hendrik Wetsten, 1683). ^ Isaac Vossius, De Nili et Aliorum Fluminum Origine [On the sources of the Nile and other rivers] (Hague (Hagæ Comitis), Netherlands: Adrian Vlacq, 1666), pages 3–7 Archived 2017-04-07 at the Wayback Machine. (chapter 2). ^ Borelli, Giovanni Alfonso De motionibus naturalibus a gravitate pendentibus (Lyon, France: 1670), page 385, Cap. 8 Prop. CLXXXV (Chapter 8, Proposition 185.). Available on-line at: Echo (Max Planck Institute for the History of Science; Berlin, Germany) Archived 2016-12-23 at the Wayback Machine.. ^ Carré (1705) "Experiences sur les tuyaux Capillaires" Archived 2017-04-07 at the Wayback Machine. (Experiments on capillary tubes), Mémoires de l'Académie Royale des Sciences, pp. 241–254. ^ See:
Josia Weitbrecht (1736) "Tentamen theoriae qua ascensus aquae in tubis capillaribus explicatur" Archived 2014-06-29 at the Wayback Machine. (Theoretical essay in which the ascent of water in capillary tubes is explained), Commentarii academiae scientiarum imperialis Petropolitanae (Memoirs of the imperial academy of sciences in St. Petersburg), 8 : 261–309. Josia Weitbrecht (1737) "Explicatio difficilium experimentorum circa ascensum aquae in tubis capillaribus" Archived 2014-11-05 at the Wayback Machine. (Explanation of difficult experiments concerning the ascent of water in capillary tubes), Commentarii academiae scientiarum imperialis Petropolitanae (Memoirs of the imperial academy of sciences in St. Petersburg), 9 : 275–309.
^ For example:
In 1740, Christlieb Ehregott Gellert (1713–1795) observed that like
mercury, molten lead would not adhere to glass and therefore the level
of molten lead was depressed in a capillary tube. See: C. E. Gellert
(1740) "De phenomenis plumbi fusi in tubis capillaribus" (On phenomena
of molten lead in capillary tubes) Commentarii academiae scientiarum
imperialis Petropolitanae (Memoirs of the imperial academy of sciences
in St. Petersburg), 12 : 243–251. Available on-line at:
Archive.org Archived 2016-03-17 at the Wayback Machine..
^ In the 18th century, some investigators did attempt a quantitative
treatment of capillary action. See, for example, Alexis Claude
Clairaut (1713–1765) Theorie de la Figure de la Terre tirée des
Principes de l'Hydrostatique [Theory of the figure of the Earth based
on principles of hydrostatics] (Paris, France: David fils, 1743),
Chapitre X. De l'élevation ou de l'abaissement des Liqueurs dans les
Tuyaux capillaires (Chapter 10. On the elevation or depression of
liquids in capillary tubes), pages 105–128. Archived 2016-04-09 at
the Wayback Machine.
^ Thomas Young (January 1, 1805) "An essay on the cohesion of fluids,"
Archived 2014-06-30 at the Wayback Machine. Philosophical Transactions
of the Royal Society of London, 95 : 65–87.
^ Pierre Simon marquis de Laplace, Traité de Mécanique Céleste,
volume 4, (Paris, France: Courcier, 1805), Supplément au dixième
livre du Traité de Mécanique Céleste, pages 1–79 Archived
2016-12-24 at the Wayback Machine..
^ Carl Friedrich Gauss, Principia generalia Theoriae Figurae Fluidorum
in statu Aequilibrii [General principles of the theory of fluid shapes
in a state of equilibrium] (Göttingen, (Germany): Dieterichs, 1830).
Available on-line at: Hathi Trust.
^ William Thomson (1871) "On the equilibrium of vapour at a curved
surface of liquid," Archived 2014-10-26 at the Wayback Machine.
Philosophical Magazine, series 4, 42 (282) : 448–452.
^ Franz Neumann with A. Wangerin, ed., Vorlesungen über die Theorie
der Capillarität [Lectures on the theory of capillarity] (Leipzig,
Germany: B. G. Teubner, 1894).
Wikimedia Commons has media related to Capillary action.
de Gennes, Pierre-Gilles; Brochard-Wyart, Françoise; Quéré, David (2004). Capillarity and Wetting Phenomena. Springer New York. doi:10.1007/978-0-387-21656-0. ISBN 978-1-4419-1833-8.