File:Pinch-off in two-fluid systems.webm

English: Here are three examples of drops of different fluids detaching from a nozzle. The movie on the left shows the pinch-off of water in air. A distinctive feature in the detachment of a water drop (and of an inviscid liquid in fact) is the pseudo-flattening of the interface of the drop just when it breaks-up. The interface is actually going inside the drop, a phenomenon known as overturning.

The movie in the center shows the pinch-off of pure glycerol, a fluid about 1000 times more viscous than water. The neck that connects the drop to the needle keeps a rather symmetric form until pinch-off.

The movie on the right shows the pinch-off of a polymeric fluid ( a water-based solution of a long-chain poly(ethylene-oxide) (PEO)). The PEO solution is known to be a visco-elastic solution, i.e. its behavior can be very close to that of a solid under appropriate stresses. The distinctive feature here is the formation of the thin thread on which the big satellite drop grows. A myriad of these satellite drops can grow, which provides the production of monodisperse drops without further treatment.