Measurement of surface tension using the "break-away" method

Surface tension is a property of the surface (boundary layer) between a fluid and a gas, such as air. The surface of a liquid behaves like a stretched elastic film. This effect is the reason that water droplets form, for example, and helps make it possible for certain insects to walk on the water or for a coin to “swim” on the water.
Experiment C3.1.2.2 determines the surface tension of water and ethanol. Here it will be shown that water is characterised by a particularly high surface tension as compared with other liquids.
(Published value for water: 0.073 Nm^-1, for ethanol: 0.022 Nm^-1).