Normal modes of vibration progression through a crystal in 1D . The amplitude of the motion has been exaggerated for ease of viewing; in an actual crystal, it is typically much smaller than the lattice spacing.
12.
Regarding their names : " When struck by its clapper, a bell vibrates in a complex way . . . In general, each normal mode of vibration contributes one " partial " to the sound of the bell.
13.
The normal modes of vibration, and the pattern of nodal lines associated with each of these, are completely determined, for a surface with homogeneous mechanical characteristics, from the geometric shape of the surface and by the way in which the surface is constrained.
14.
In general, a molecule with " N " atoms has 3 " N " 6 normal modes of vibration, but a " linear " molecule has 3 " N " 5 such modes, because rotation about its molecular axis cannot be observed.
