surface tension


surface tension
the elasticlike force existing in the surface of a body, esp. a liquid, tending to minimize the area of the surface, caused by asymmetries in the intermolecular forces between surface molecules.
[1875-80]

* * *

Property of a liquid surface that causes it to act like a stretched elastic membrane (see elasticity).

Its strength depends on the forces of attraction among the particles of the liquid itself and with the particles of the gas, solid, or liquid with which it comes in contact. Surface tension allows certain insects to stand on the surface of water and can support a razor blade placed horizontally on the liquid's surface, even though the blade may be denser than the liquid and unable to float. Surface tension results in spherical drops of liquid, as the liquid tends to minimize its surface area.

* * *

      property of a liquid surface displayed by its acting as if it were a stretched elastic membrane. This phenomenon can be observed in the nearly spherical shape of small drops of liquids and of soap bubbles. Because of this property, certain insects can stand on the surface of water. A razor blade also can be supported by the surface tension of water. The razor blade is not floating: if pushed through the surface, it sinks through the water.

      Surface tension depends mainly upon the forces of attraction between the particles within the given liquid and also upon the gas, solid, or liquid in contact with it. The molecules in a drop of water, for example, attract each other weakly. Water molecules well inside the drop may be thought of as being attracted equally in all directions by the surrounding molecules. However, if surface molecules could be displaced slightly outward from the surface, they would be attracted back by the nearby molecules. The energy responsible for the phenomenon of surface tension may be thought of as approximately equivalent to the work or energy required to remove the surface layer of molecules in a unit area. Surface tension may be expressed, therefore, in units of energy (joules) per unit area (square metres). Water has a surface tension of 0.07275 joule per square metre at 20° C (68° F). In comparison, organic liquids, such as benzene and alcohols, have lower surface tensions, whereas mercury has a higher surface tension. An increase in temperature lowers the net force of attraction among molecules and hence decreases surface tension.

      Surface tension is also viewed as the result of forces acting in the plane of the surface and tending to minimize its area. On this basis, surface tension is often expressed as an amount of force exerted in the surface perpendicular to a line of unit length. The unit then is newtons per metre, which is equivalent to joules per square metre.

* * *


Universalium. 2010.

Look at other dictionaries:

  • surface tension — n the attractive force exerted upon the surface molecules of a liquid by the molecules beneath that tends to draw the surface molecules into the bulk of the liquid and makes the liquid assume the shape having the least surface area * * * the… …   Medical dictionary

  • surface tension — ► NOUN ▪ the tension of the surface film of a liquid, which tends to minimize surface area …   English terms dictionary

  • Surface tension — Sur face ten sion (Physics) That property, due to molecular forces, which exists in the surface film of all liquids and tends to bring the contained volume into a form having the least superficial area. The thickness of this film, amounting to… …   The Collaborative International Dictionary of English

  • surface tension — n [U] the way the ↑molecules in the surface of a liquid stick together so that the surface is held together …   Dictionary of contemporary English

  • surface tension — n. a property of liquids in which the exposed surface tends to contract to the smallest possible area because of unequal molecular cohesive forces near the surface: measured by the force per unit of length …   English World dictionary

  • surface tension — noun uncount TECHNICAL the force by which the molecules of a liquid stay close together at the surface to form the smallest possible area …   Usage of the words and phrases in modern English

  • Surface tension — For the work of fiction, see Surface Tension (short story). Surface tension is a property of the surface of a liquid that causes it to behave as an elastic sheet. It allows insects, such as the water strider (pond skater, UK), to walk on water.… …   Wikipedia

  • surface tension — noun a phenomenon at the surface of a liquid caused by intermolecular forces (Freq. 4) • Hypernyms: ↑physical phenomenon • Hyponyms: ↑capillarity, ↑capillary action, ↑interfacial tension, ↑interfacial surface tension …   Useful english dictionary

  • surface tension — paviršinės įtempties koeficientas statusas T sritis Standartizacija ir metrologija apibrėžtis Jėga, statmena ilginiam paviršiaus elementui, padalyta iš to elemento ilgio. atitikmenys: angl. surface tension vok. Oberflächenspannungskonstante, f… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

  • surface tension — paviršinė įtemptis statusas T sritis Standartizacija ir metrologija apibrėžtis Dydis, išreiškiamas jėgos, mažinančios skysčio paviršiaus plotą ir statmenos ilginiam paviršiaus elementui, ir to elemento ilgio dalmeniu. atitikmenys: angl. surface… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.