A Safer Alternative for the Mercury Beating Heart Demonstration

Abstract

The mercury beating heart is a classic demonstration to introduce redox reactions in the classroom. Here we report a new, safer demonstration: the Galinstan beating heart. Galinstan is a commercially available eutectic alloy composed of gallium (68.5%), indium (21.5%), and tin (10%) that has low toxicity. When an iron nail touches the Galinstan drop in a sulfuric acid solution, a steady beating heart behavior is observed. The mechanism of the Galinstan beating heart was attributed to electron transfer from the Galinstan drop to the iron nail, which induces a charge redistribution and an interfacial tension gradient on the drop.

Directional Motion of Gallium-Based Liquid Metal Induced by Asymmetric Chemical Surrounding

“…Gallium-based metal alloys provide an alternative to mercury as they not only have fluidity at room temperature but also have low vapor pressure and are nontoxic. This means these metals can serve as safer demonstrations. − In a previous demonstration, gallium and its alloys formed a beating heart that occurred in a uniform solution, where oscillations were induced by the periodic change of surface tension. Self-propulsion or deformation of the liquid metals resulted from a surface tension gradient , that was derived from ionic imbalance, redox reaction, − or electric field. , …”

A Demonstration of Silver with Various Morphology Recovered from Wastewater

“…These limitations restrain their application in live demonstration. 20 Polyaniline has good stability and a certain ability to selectively reduce precious metals and has potential application value in the field of precious metal recovery. According to research on the reduction of Ag + by polyaniline, the recovery rate can reach 96.1% of the theoretical value.…”

“…Therefore, there are some limitations to the use of the above methods for related science demonstrations, especially since these methods are complex to operate or the experimental equipment is expensive to use. These limitations restrain their application in live demonstration …”

Direct Current (DC) Electric Field-Enabled Beating Heart of Ga-Based Liquid Metal

“…In our recent study, we introduced another safer substitute for the MBH demonstration: the Galinstan beating heart demonstration (GBH) . This GBH involves only Galinstan, sulfuric acid, and an iron nail.…”

“…21 In our recent study, we introduced another safer substitute for the MBH demonstration: the Galinstan beating heart demonstration (GBH). 22 This GBH involves only Galinstan, sulfuric acid, and an iron nail. Galinstan is a eutectic alloy consisting of gallium (68.5%), indium (21.5%), and tin (10%), which is commercially available or can be synthesized.…”