Coalescence is a research area that focuses on the physical process by which two or more droplets, bubbles, or particles merge to form a larger entity. This phenomenon occurs in a wide range of natural and industrial processes, including cloud formation, oil recovery, and pharmaceutical development. Researchers in this field study the mechanisms and dynamics of coalescence, as well as the effects of various factors such as surface tension, viscosity, and external forces on the process. Understanding coalescence is important for optimizing processes in various industries and for improving our knowledge of complex systems in nature.