The Bakerian Lecture, 1971. The physics of the thunderstorm

Although I have entitled this lecture ‘The physics of the thunderstorm’ I shall, in fact, treat only of its electrification. I shall not deal in detail with the cloud dynamics, or with the physics of raindrops and hailstones, full treatments of which may be found in Mason (1971). Nor shall I discuss the structure and mechanism of the lightning discharge, but concentrate almost entirely on the various mechanisms by which electric charge may be generated and separated to supply the lightning flashes. The approach will be, to some extent, a personal one based on researches which my colleagues and I have carried out intermittently for nearly 20 years. This is, for me, the most intriguing and challenging problem in cloud physics, with a strong incentive to understand one of the most spectacular of natural phenomena, but made all the more interesting by the fact that the search for a convincing solution has led us into a number of rather difficult areas of classical physics, and to a deeper study of the fundamental properties of water and ice.