Sound

The Speed of Sound

v = f x wavelength

Sound obeys the same wave relation; a clean 170 Hz at 2 m gives 340 m/s, about the real speed of sound in air.

Example

Sound obeys the same wave relation; a clean 170 Hz at 2 m gives 340 m/s, about the real speed of sound in air.

highlighted = computed this step

Sound obeys the same wave relation

A sound wave travels at speed equals frequency times wavelength, just like any wave. Its speed is set by the air it moves through, not by how loud or high the note is.

v=f λv = f\,\lambda
A sound wave: pressure against positionA pressure-versus-position curve representing the sound wave in the air.pressure

A worked value near the real speed of sound

A 170 hertz note with a 2 metre wavelength travels at 170 times 2, or 340 metres per second — about the real speed of sound in air, which depends on the air's temperature.

v=f λ=170 Hz ⋅ 2 m=340 m/sv = f\,\lambda = 170\ \text{Hz} \,\cdot\, 2\ \text{m} = \hl{340}\ \text{m}/\text{s}
waves 170 Hz times 2 m is a clean 340 m/s, near the real speed of sound.