It is a commonly held, but misconceived, view that glass flows to an appreciable extent over long periods of time. According to the flowing glass theory, glass is a highly viscous liquid comparable to pitch only even more viscous.
Possible reasons for the belief that glass flows edit
There appears to be two key explanations for the existence of the belief:
- The belief is linked to the urban legend that there are antique panes of glass that have become distorted over a matter of centuries (as discussed below).
- The unusual molecular structure of glass - glass is an amorphous solid - can cause confusion. Amorphous solids are sometimes explained as "supercooled liquids". However, this phrase does not imply that an amorphous solid has any of the material properties of a liquid. [1]