Principle

The force is measured on a ring shortly before a liquid film tears using a torsion meter. The surface tension is calculated from the diameter of the ring and the tear-off force.

Benefits


High sensitivity measurement possible thanks to ring method

Analogue set-up that can also be used as a demo experiment in the lecture hall

Torsion dynamometer used can measure very small forces and is therefore suitable to measure other electrostatic and magnetic interactions between bodies

Interdisciplinary use also in applied sciences or physical chemistry


Tasks


Determine the surface tension of olive oil as a function of temperature.

Determine the surface tension of water/methanol mixtures as functions of the mixture ratio.


What you can learn about


Surface energy

Interface

Surface tension

Adhesion

Critical point

Eötvös equation