School of Physics Lecture Demonstration Manual

Fb-1 Force Exerted by a Soap Film

Published: Thursday 09 March 2006 - Updated: Tuesday 29 March 2011


To demonstrate that liquid surfaces are in a state of tension.



Click on pictures to enlarge.

Soap Bubble Diagram


A soap film is formed on the rectangular wire frame and placed on the overhead projector. That the film exerts a force may be demonstrated by the fact that a force is necessary to increase its area. If desired a small weight may be added to the connecting cotton.

Safety notes

Electrical Safety 

Chemical Safety 

Sharps Safety 


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