thumb|upright=1.2|Figure 4 The temperature-induced translational motion of particles in solids takes the form of phonons. Shown here are phonons with identical amplitudes but with wavelengths ranging from 2 to 12 average inter-molecule separations (a).
thumb|upRight=1.2|fIgUre 4 the temPerATurE-indUced trANslatioNAL motion Of ParTicLEs iN SolIds Takes the form Of pHOnONs. Shown here are phononS with iDentIcal aMpLItuDEs but wITh wavelenGths ranging From 2 To 12 aVeRage inTer-moLecUle sePAratIons (a).