Page "Thermal conductivity" Paragraph 47

Heat transport in both glassy and crystalline dielectric solids occurs through elastic vibrations of the lattice ( phonons ).

This transport is limited by elastic scattering of acoustic phonons by lattice defects.

These predictions were confirmed by the experiments of Chang and Jones on commercial glasses and glass ceramics, where mean free paths were limited by " internal boundary scattering " to length scales of 10 < sup >− 2 </ sup > cm to 10 < sup >− 3 </ sup > cm.