Follow @physics_unplugged | video description 👇 The speed of sound describes how fast vibrations travel through a medium. At 20°C or 68°F, the speed of sound in air is approximately 343 m/s (1,235 km/h). This results in about 2.91 seconds to cover a kilometer and 4.69 seconds to travel a mile. Curiously enough, in warmer air, sound moves faster because the particles move more easily. Comparatively speaking, sound in water travels at a speed of about 1,480 m/s-more than four times as fast as in