Sound travels 15 times faster through steel than through air
Sound travels at about 343 metres per second through air at room temperature. Through water it travels at about 1,480 m/s. Through steel it travels at about 5,120 m/s — roughly 15 times faster than air. Sound speed depends on the density and elasticity of the medium: denser, more elastic materials transmit sound waves faster. This is why you can hear an approaching train by putting your ear to the rail long before you hear it through air — the rail conducts the vibration directly.
We experience sound entirely through air and intuitively think of it as an airborne phenomenon with a fixed speed. Learning that its speed varies by a factor of 15 based on material makes sound feel more like a mechanical phenomenon — which it is.
“Sound travels 15× faster through steel than through air. You can hear an approaching train through the rail far before you hear it in the air — this is why. 🎵 #OddlyHuman”