The properties of a water drop floating on the surface of liquid nitrogen are studied, a type of Leidenfrost effect. Heat extracted from the water drop evaporates the liquid nitrogen under it, forming a gaseous dimple that the drop floats on. The temp...
The properties of a water drop floating on the surface of liquid nitrogen are studied, a type of Leidenfrost effect. Heat extracted from the water drop evaporates the liquid nitrogen under it, forming a gaseous dimple that the drop floats on. The temperature of the drop falls with time, finally reaching a Leidenfrost temperature where the ice crystal sinks into the nitrogen. We show a simplified force-balance theory, including thermal conduction and vapor and surface tension forces where the vapor force is considered to have only a radial component, which is dominant. The total floating time corresponds to how long the temperature of the water drop takes to go from the initial temperature to the Leidenfrost temperature.