Superheating

This article is about the phenomenon where a liquid can exist in a metastable state above its boiling point. For pressurized water above 100 °C, see superheated water. For the device used in steam engines, see superheater. For the 'superheat' used in vapor-compression refrigeration, see Vapor-compression refrigeration § Thermodynamic analysis of the system.

In thermodynamics, superheating (sometimes referred to as boiling retardation, or boiling delay) is the phenomenon in which a liquid is heated to a temperature higher than its boiling point, without boiling. This is a so-called metastable state or metastate, where boiling might occur at any time, induced by external or internal effects.[1][2] Superheating is achieved by heating a homogeneous substance in a clean container, free of nucleation sites, while taking care not to disturb the liquid.

This may occur by microwaving water in a very smooth container. Disturbing the water may cause an unsafe eruption of hot water and result in burns.[3]

  1. ^ Debenedetti, P.G.Metastable Liquids: Concepts and Principles; Princeton University Press: Princeton, NJ, USA, 1996.
  2. ^ Maris, H., Balibar, S. (2000) "Negative Pressures and Cavitation in Liquid Helium" Physics Today 53, 29
  3. ^ Health, Center for Devices and Radiological (2018-11-03). "Risk of Burns from Eruptions of Hot Water Overheated in Microwave Ovens". FDA.