The Effect of Air Bubbles in Ice on Charge Transfer Produced by Asymmetric Rubbing

Abstract

Experiments showed that, when a brass cube coated with transparent bubble-free ice or opaque ice containing a high concentration of air bubbles was allowed to slide down an opaque or transparent ice incline, temperature differences were created between the ice specimens and charge was separated. In all cases the cube ice acquired negative charge if asymmetric rubbing caused it to become warmer than the ice incline, and positive charge if it became colder. These observations are consistent with the predictions of Hobbs and are explicable qualitatively in terms of the temperature-gradient theory. The magnitude of the charge transfer was in approximate agreement with the theory if both contacting ice specimens were transparent, but was appreciably greater than predicted if either or both of the specimens contained a high proportion of air bubbles.