🪨 Speed of Sound in Solids Calculator

Sound Speed in a Solid Rod

Sound travels through solids much faster than through air because solids are much stiffer relative to their density. For a long, thin rod, the longitudinal wave speed is v = √(E/ρ), where E is Young’s modulus (a measure of stiffness) and ρ is the material’s density.

This explains why sound moves through steel (about 5,900 m/s) roughly 17 times faster than through air (about 343 m/s) — steel is both very stiff and reasonably dense, and the stiffness effect dominates. This simplified 1D formula is most accurate for thin rods; for bulk solids, additional terms (Poisson’s ratio) come into play.