All liquids have a surface tension, which can, for example, explain why you can fill a glass with water up over the edge of the glass without the water overflowing.
The surface tension can explain why some liquids foam, and it can also explain why liquids can creep up the edge of a glass or pull up into a thin tube.
In the Center for Plastics and Packaging, we can measure the surface tension of liquids on a tensiometer, which is equipped with a Du Noüy ring.
The method works by pulling the ring up by the liquid, at the same time as the traction force is measured.
The maximum measured force is used to calculate the surface tension of the liquid.
In connection with the measurement, measurement of the density of the liquid is also performed.