Short answers, pulled from the story.
Modern cloud physics began in the 19th century with Otto von Guericke originating the idea that clouds were composed of water bubbles in 1358. Augustus Waller used spider web to examine droplets under the microscope in 1847.
The water droplets in a cloud have a normal radius of about 0.002 mm (0.00008 in). Droplets suspended in the air will interact with each other either by colliding and bouncing off each other or by combining to form a larger droplet.
High-level clouds form at altitudes of 5 to 12 kilometers while mid-level clouds occupy ranges between 2 to 7 kilometers. Low level clouds exist around 2 kilometres or lower without height-related prefixes.
Saturation vapor pressure with respect to ice is lower than saturation vapor pressure with respect to water which causes extra water vapor to condense into ice on surface of particle forming larger ice crystals. This process happens only at temperatures between -40°C and 0°C.
Satellites gather data about cloud properties using instruments such as MODIS POLDER CALIPSO or ATSR. Instruments measure radiances from which relevant parameters can be retrieved through inverse theory.