School of Physics Lecture Demonstration Manual

Fb-6 Reducing Surface Tension

Published: Friday 10 March 2006 - Updated: Tuesday 29 March 2011

Aim

To demonstrate the reduction of surface tension.

Apparatus

Diagrams

Click on pictures to enlarge.

Reducing Surface Tension Diagram

Description

A stocking floats in a beaker of clean water. The addition of a few drops of soap solution reduces the surface tension sufficiently and the stocking sinks.

A large droplet of water is placed on the wire gauze mat. The surface tension of the water gives it its roughly spherical shape. The addition of a small drop of soap solution reduces its surface tension and "spreads" the drop.

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