[4] His work on the kinetic theory of gases, solar-terrestrial physics, and the Earth's ozone layer has inspired a broad range of research over many decades.

[6] He began his research in pure mathematics under G. H. Hardy, but later that year was asked by Sir Frank Dyson to be his chief assistant at the Royal Greenwich Observatory.

[citation needed] From 1914 to 1919, Chapman returned to Cambridge as a lecturer in mathematics and a fellow of Trinity.

Chapman is credited with working out, in 1930, the photochemical mechanisms that give rise to the ozone layer.

[5] In 1946 Chapman coined the term: Aeronomy, which is used today to describe the scientific field of high-altitude research into atmosphere/space interaction.

[citation needed] Chapman was President of the Special Committee for the International Geophysical Year (IGY).

The idea of the IGY stemmed from a discussion in 1950 between Chapman and scientists including James Van Allen.

The IGY was held in 1957–58, and resulted in great progress in fields including Earth and space sciences, as well as leading to the first satellite launches.

[18] The American Geophysical Union organises "Chapman Conferences," which are small, topical meetings intended to foster innovative research in key areas.