Water vapour is a shield against heat

The drop hovers above a layer of water vapour. It will not remain intact forever, as the steam under the drop is gradually replaced by water from the drop. The intense heat from the hotplate makes the water touching the hotplate evaporate, but rather than dispersing, it is captured under the water drop. The steam under the drop functions as a cushion between the hotplate and the water drop.

H E AT STEAM WAT E R D R O P UP TO 0.2 MM HOT S U R FA C E