Abstract

In 1750 Benjamin Franklin proposed an experiment to demonstrate the electrical basis of thunderstorm lightning by flying a kite into a storm cloud thereby extracting sparks. The principle was demonstrated in 1752 by Dalibard who replaced the kite with a 12 meter metal rod, launching international investigations into the nature of electricity which rather quickly led to Franklin’s being awarded the Copley Medal of the Royal Society in 1753. Nearly 260 years later the study of thunderstorm electrification is no less active but is rather more focused. It has been understood from detailed field studies and simulations that active collisions between ice particles underlies lightning but the microscopic mechanism of charge separation requires a rather detailed understanding of, inter- alia, the intrinsic quasi-steady electrodynamics of ions in ice, surface physics, and long ranged intermolecular forces. Such phenomena turn out to be implicated in the agglomeration of matter during the formation of planetesimals in solar nebula, the redistribution of particles in comets, the tailoring of the properties of composite materials and Onsager reciprocity in systems where the solvent is frozen.