Alternative methods for the reduction of evaporation: practical exercises for the scienceclassroom

Abstract

Across the world, freshwater is valued as the most critically important natural resource, asit is required to sustain the cycle of life. Evaporation is one of the primary environmentalprocesses that can reduce the amount of quality water available for use in industrial,agricultural and household applications. The effect of evaporation becomes intensifiedespecially during conditions of drought, particularly in traditionally arid andsemi-arid regions, such as those seen in a number of countries over the past ten years.In order to safeguard against the influence of droughts and to save water frombeing lost to the evaporative process, numerous water saving mechanisms havebeen developed and tested over the past century. Two of the most successful andwidely used mechanisms have included floating hard covers and chemical filmmonolayers. This article describes a laboratory based project developed for senior highschool and first year university classes, which has been designed to introducestudents to the concepts of evaporation, evaporation modelling and water lossmitigation. Specifically, these ideas are delivered by simulating the large scaledeployment of both monolayers and floating hard covers on a small water tank undernumerous user defined atmospheric and hydrodynamic conditions, including varyingsurface wind speeds and underwater bubble plumes set to changing flow rates.