The chapter introduces the reader to the fluid-related problems associated with discrete small volumes. The sizes that might be reasonable by now in the scientific community—micrometers, nanometers—affect the fluids by a power of three as fluids mainly consist of spherical particles. Specific physical quantities that characterize the fluids are virtually impossible to measure when the droplets of the fluids are micrometer-sized droplets and in the femtograms weight range. Devices capable of reaching to those ranges are scarce and the influences of the environmental conditions at such levels become extremely significant. One example of such particles is liposomes—volumes of organic matter in the nanometer size range which embed useful chemicals and which can target specific tissues within the human body.