How Fast Is Speed of Sound in Steel?

Sound travels at 5,000 m/s through steel — 15× faster than in air. Press your ear to a steel rail and you can hear an oncoming train kilometres before any sound reaches you through the air. This was old railway-worker lore long before stethoscopes used the same principle.

Sound travels even faster through diamond — about 12,000 m/s — making diamond an ideal material for ultrasonic precision instruments.

• 15× faster than sound in air
• Hear trains kilometres ahead through rails