A spontaneous breakup of a liquid jet results in the formation of a chain of droplets, which is a daily observed phenomenon, such as in the raining process and under an open water-faucet. We here report inkjet printing experiments for the formation of droplets which are inconsistent with existing theories and thereafter propose a novel concept of surface area minimization to address the droplet-formation condition. The novel concept is also capable of predicting the formation of satellite and subsatellite droplets, which cannot be comprehended by the classic Rayleigh theory for the formation of droplets. We also present a new evolution behavior of liquid jets not yet reported before that the jet initially transforms into droplets and then becomes a uniform-radius jet again. The current results can be applied to a variety of disciplines where liquid jets are present.
