  The physics of foams and emulsions has traditionally been studied using bulk
foam/emulsion tests and single film platforms such as the Scheludko cell.
Recently there has been a renewed interest in a third class of techniques that
we term as single bubble/drop tests, which employ isolated whole bubbles and
drops to probe the characteristics of foams and emulsions. Single bubble and
drop techniques provide a convenient framework for investigating a number of
important characteristics of foams and emulsions, including the rheology,
stabilization mechanisms, and rupture dynamics. In this review we provide a
comprehensive discussion of the various single bubble/drop platforms and the
associated experimental measurement protocols including the construction of
coalescence time distributions, visualization of the thin film profiles and
characterization of the interfacial rheological properties. Subsequently, we
summarize the recent developments in foam and emulsion science with a focus on
the results obtained through single bubble/drop techniques. We conclude the
review by presenting important venues for future research.
