The discussion revolves around the heat energy contained in molten glass, particularly focusing on how much energy would be lost during the cooling process of a cubic meter of glass. Participants explore the specific heat capacity of glass, the concept of latent heat, and the physical properties of glass as it transitions from a molten state to a solid state.
Participants express differing views on whether glass has a latent heat of fusion and the implications of its physical properties. The discussion remains unresolved regarding the characterization of glass and the reasons for the thickness of old window glass.
Participants acknowledge that the specific heat capacity of glass may change with temperature, and there are unresolved questions about the definitions and implications of phase transitions in glass.
Thank you =)Khashishi said:Depends on the temperature. Here's the specific heat capacity of (some kind of) glass at 20C. It probably changes as you go up in temperature, but this should get you a rough estimate.
http://hyperphysics.phy-astr.gsu.edu/hbase/tables/sphtt.html
Some people claim that glass is actually a supercooled liquid because there is no first order phase transition as it cools. In fact, there is a second order transition between the supercooled liquid state and the glass state, so a distinction can still be drawn. The transition is not as dramatic as the phase change that takes you from liquid to crystalline solids. There is no discontinuous change of density and no latent heat of fusion. The transition can be detected as a marked change in the thermal expansivity and heat capacity of the material. [my emphasis]
http://math.ucr.edu/home/baez/physics/General/Glass/glass.html
CWatters said:Does glass have a latent heat of fusion/melting?
Also, there is a belief that the glass in old windows is thicker at the bottom than at the top because it has 'flowed downwards'. I think the reason is not to do with flowing but because the glass was always put in that way for strength.Vanadium 50 said:It does not. (But the "glass is a liquid" meme is an oversimplification designed more to produce a 'wow' than actual enlightenment)