Freezing point is the temperature at which a liquid becomes a solid at normal atmospheric pressure. Alternatively, a melting point is the temperature at which a solid becomes a liquid at normal atmospheric pressure. A more specific definition of freezing point is the temperature at which solid and liquid phases coexist in equilibrium. The normal freezing point is the temperature at a substance melts (or freezes) at one atmosphere (760 torr = 760 mm Hg = 14.7 psi = 101.3 kPa) of pressure. Additional Info: Melting points can be determined by visual inspection or by monitoring the temperature of the liquid with time. When the freezing point is reached, the temperature of the solution will no longer drop until all the liquid has frozen. Melting points may be lowered (depressed) by the addition of a soluble material to the solution. The degree of lowering depends on the solvent and is easily predicted using a simple equation (see below). MSDS Relevance: The freezing/melting point is an important material property to know. Some materials must be prevented from freezing to protect their integrity or the product packaging. Likewise, many materials may expand when heated above their melting point and may overflow or burst their container. The freezing/melting point is one of the items that OSHA requires to be on an MSDS. See also: Boiling Point, Vapor Pressure