Surface tension effects of surface tension can be seen with ordinary water: Surface tension is visible in other common phenomena, especially when surfactants are used to decrease it: Surface tension, represented by the symbol "γ" (alternatively "σ" or "T"), is measured in force per unit length. Its SI unit is newton per meter but the cgs unit of dyne per centimeter is also used. For example, Surface tension can be defined in terms of force or energy. In terms of force: surface tension of a liquid is the force per unit length. In the illustration on the right, the rectangular frame, composed
Tensiometer (surface tension) use. For interfacial tension measurements, buoyancy of the probe needs to be taken into account which complicates the measurement. This method uses a rod which is lowered into a test liquid. The rod is then pulled out of the liquid and the force required to pull the rod is precisely measured. The method isn't standardized but is sometimes used. The Du Noüy-Padday rod pull tensiometer will take measurements quickly and will work with liquids with a wide range of viscosities. Interfacial tensions cannot be measured. Due to internal attractive forces of a liquid, air bubbles within the liquids are compressed.