The Ultrasonic Soda Fountain:A Dramatic Demonstration of Gas Solubility in Aqueous Solutions

摘要

The solubility of gases in liquids is a fundamental con-cept that is explored in classrooms from grade school through college.Common demonstrations of gas solubility range from comparisons of carbonation in warm versus cold beverages at the primary school level through measurements of Henry's law constants in the undergraduate laboratory (1,2).We de-scribe a simple yet dramatic demonstration suitable for introducing the concept of gas solubility by exposing a carbonated beverage (uncapped)to ultrasonic energy in a common laboratory ultrasonic cleaner.As shown in Figure 1,the sudden degassing of the solution through the narrow bottle top produces a dramatic,foaming fountain that can reach a height of several meters.For advanced level classes,the demonstration might be used to introduce the dynamic aspect of gas solubility in liquids and nucleation in liquids supersaturated with gas.