Early Laboratory Measurements in Water and Dilute Solutions

Abstract

This chapter describes some early measurements of EFP developed during freezing of water and solutions. Gill and Alfrey of the Clarendon Laboratory of the Department of Physics in Oxford University, England, immersed a copper block cooled to liquid air temperatures into liquid water and measured freezing potentials (ice positive) up to 50V between the copper block and a wire electrode in water. They found higher potentials with faster rates of cooling or freezing. After these initial experiments, several investigators studied the development of electrical potentials developed during the freezing of pure water and in dilute aqueous solutions containing different ions. The highest values of EFP measured by Cobb and Gross and Gross et al., were in dilute solutions (10 to 15 micromolar) of ammonium salts (chloride, carbonate, acetate). Korkina describes the measurement of EFP in freezing dilute solutions containing ions of Fe, Ca, Na, and ammonia.