This article reviews two approaches to exploring collisions and reactions between gases and liquids. We first describe molecular beam scattering experiments, which reveal the detailed ways in which gas atoms and molecules scatter from, accommodate on, and react with low vapor pressure liquids. We then discuss droplet flow tube experiments, which uncover the kinetics of the uptake of reactive and nonreactive gases in water and in aqueous solutions. Our goals are to develop simple, predictive rules for describing the fate of gas molecules coming into contact with the surface of liquids.