In chemical education, repetitive and large-scale motion
of material
in a chemical reaction could effectively capture students’
attention and stimulate their interests to further explore the underlying
science. Gallium-based liquid metals are more safe and suitable for
some classroom demonstrations than mercury to introduce chemical principles.
In this article, we describe a visually striking experiment using
Ga-based liquid metal. Repetitive and large-scale deformation of liquid
metal was observed in an acidified solution of either copper(II) chloride
or ferric(III) chloride. To elucidate the mechanism of deformation,
the chemical reaction and the interfacial tension are discussed. Deformation
can be attributed to a spatial and temporal imbalance of the interfacial
tension on the liquid metal induced by the chemical reactions. The
simple setups and readily available chemicals enable this experiment
to be a suitable and safe classroom demonstration.