Editing Speed of sound (section)

====One-dimensional solids====
The speed of sound for pressure waves in stiff materials such as metals is sometimes given for "long rods" of the material in question, in which the speed is easier to measure. In rods where their diameter is shorter than a wavelength, the speed of pure pressure waves may be simplified and is given by:<ref name="Kinsler2000"/>{{rp|pages=[https://archive.org/details/fundamentalsacou00kins_265/page/n85 70]}}
<math display="block">c_{\mathrm{solid}} = \sqrt{\frac{E}{\rho}},</math>
where {{math|''E''}} is [[Young's modulus]]. This is similar to the expression for shear waves, save that [[Young's modulus]] replaces the [[shear modulus]]. This speed of sound for pressure waves in long rods will always be slightly less than the same speed in homogeneous 3-dimensional solids, and the ratio of the speeds in the two different types of objects depends on [[Poisson's ratio]] for the material.