School of Physics Lecture Demonstration Manual

Fb-9 Mercury Gobbler

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


To demonstrate that electrical and chemical effects can vary the surface tension.



Click on pictures to enlarge.

Mercury Gobbler Diagram


The demonstration consists of a blob of mercury in dilute Nitric acid with a few grains of Potassium Dichromate added. The electrical and chemical effects at the surface leads to surface motions that cause the mercury to swim towards the Potassium Dichromate crystals.

Safety notes

Electrical Safety 

Chemical Safety 

Sharps Safety 

Personal Protection 


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