Abstract: The properties of a fluid body in the form of a surface-attached droplet/bubble can be determined. A data set is stored describing a plurality of droplets/bubbles of different shapes; each shape is captured as a combination of two or more linear dimensional measurements. For each shape the data set includes one or more parameters describing the relationship between the physical properties of a pair of fluids capable of forming that shape as a surface-attached droplet/bubble disposed in a surrounding fluid medium. A fluid body is provided in the form of a surface-attached droplet/bubble and a plurality of linear dimensional measurements are taken and provided as input to a processing apparatus. Processing apparatus determines from the data set the one or more parameters associated with the shape described by said linear dimensional measurements. Particular the surface tension of a fluid can be found in this way based on simple dimensional measurements.