Skip to main content

surface tension

surface tension Symbol γ. The property of a liquid that makes it behave as if its surface is enclosed in an elastic skin. The property results from intermolecular forces: a molecule in the interior of a liquid experiences a force of attraction from other molecules equally from all sides, whereas a molecule at the surface is only attracted by molecules below it in the liquid. The surface tension is defined as the force acting over the surface per unit length of surface perpendicular to the force. It is measured in newtons per metre. It can equally be defined as the energy required to increase the surface area by one square metre, i.e. it can be measured in joules per metre squared (which is equivalent to N m–1).

The surface tension of water is very strong, due to the intermolecular hydrogen bonding, and is responsible for the formation of drops, bubbles, and meniscuses (the curved surfaces of columns of liquid), as well as the rise of water in a capillary tube (capillarity), the absorption of liquids by porous substances, and the ability of liquids to wet a surface. Capillarity is very important in plants as it contributes to the transport of water, against gravity, within the plant.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"surface tension." A Dictionary of Biology. . Encyclopedia.com. 25 Mar. 2017 <http://www.encyclopedia.com>.

"surface tension." A Dictionary of Biology. . Encyclopedia.com. (March 25, 2017). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/surface-tension-0

"surface tension." A Dictionary of Biology. . Retrieved March 25, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/surface-tension-0

surface tension

surface tension, tendency of liquids to reduce their exposed surface to the smallest possible area. A drop of water, for example, tends to assume the shape of a sphere. The phenomenon is attributed to cohesion, the attractive forces acting between the molecules of the liquid (see adhesion and cohesion). The molecules within the liquid are attracted equally from all sides, but those near the surface experience unequal attractions and thus are drawn toward the center of the liquid mass by this net force. The surface then appears to act like an extremely thin membrane, and the small volume of water that makes up a drop assumes the shape of a sphere, held constant when an equilibrium between the internal pressure and that due to surface tension is reached. Because of surface tension, various small insects are able to skate across the surface of a pond, objects of greater density than water can be made to float, and molten lead when dropped into a cool liquid forms suddenly into shot. See capillarity.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"surface tension." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. 25 Mar. 2017 <http://www.encyclopedia.com>.

"surface tension." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (March 25, 2017). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/surface-tension

"surface tension." The Columbia Encyclopedia, 6th ed.. . Retrieved March 25, 2017 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/surface-tension

surface tension

surface tension (γ) Fluid surfaces may take on the behaviour of a stretched elastic membrane as a result of the tendency of a liquid surface to contract. The surface tension of a liquid is given as the tension across a unit length of the fluid surface. Surface tension is temperature-dependent and is closely associated with capillarity.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"surface tension." A Dictionary of Earth Sciences. . Encyclopedia.com. 25 Mar. 2017 <http://www.encyclopedia.com>.

"surface tension." A Dictionary of Earth Sciences. . Encyclopedia.com. (March 25, 2017). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/surface-tension

"surface tension." A Dictionary of Earth Sciences. . Retrieved March 25, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/surface-tension

surface tension

sur·face ten·sion • n. the tension of the surface film of a liquid caused by the attraction of the particles in the surface layer by the bulk of the liquid, which tends to minimize surface area.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"surface tension." The Oxford Pocket Dictionary of Current English. . Encyclopedia.com. 25 Mar. 2017 <http://www.encyclopedia.com>.

"surface tension." The Oxford Pocket Dictionary of Current English. . Encyclopedia.com. (March 25, 2017). http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/surface-tension

"surface tension." The Oxford Pocket Dictionary of Current English. . Retrieved March 25, 2017 from Encyclopedia.com: http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/surface-tension