Technical data

Surface tension with the ring method (Du Nouy method)

Article no: P2140500

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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

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.

Learning objectives

Surface energy
Interface
Surface tension
Adhesion
Critical point
Eötvös equation

Scope of delivery

Torsion dynamometer, 0.01 N	02416-00	1
Surface tension measuring ring	17547-00	1
Retort stand, h = 750 mm	37694-00	1
Supp.rod stainl.st.,50cm,M10-thr.	02022-20	1
Magnetic stirring bar 30 mm, cylindrical	46299-02	1
Universal clamp	37715-01	2
Right angle boss-head clamp	37697-00	2
Right angle clamp expert with fulcrum screw	02054-00	1
Crystallising dishes, Boro, various sizes	46245-00	2
Crystallising dishes, Boro, various sizes	46244-00	2
Silk thread, l = 200 m	02412-00	1
Glass tubes,straight, 150 mm, 10	MAU-16074542	1
Stopcock,1-way,straight, glass	36705-00	1
Silicone tubing, various diameters	39296-00	2
Bulb pipettes, various sizes	36578-00	1
Bulb pipettes, various sizes	36579-00	1
Pipettor	36592-00	1
Pipette dish	36589-00	1
Graduated cylinders, Boro, various sizes	36629-00	1
Ethyl alcohol, absolute 500 ml	30008-50	1
Olive oil,pure 100 ml	30177-10	5