The Velocity of Information
Wave speed ($v$) is the velocity at which a wave disturbance propagates through a medium. Whether it's sound through air, ripples on a pond, or light through a vacuum, the fundamental relationship between speed, frequency, and wavelength remains the same.
Speed vs. Medium
It is important to remember that wave speed is primarily determined by the properties of the medium, not the wave itself:
- Sound: Travels faster in solids (like steel) than in liquids (like water), and faster in liquids than in gases (like air).
- Light: Travels fastest in a vacuum ($299,792,458 , \text{m/s}$). It slows down slightly in air and significantly in glass or water.
- Strings: The speed of a wave on a guitar string depends on the tension and the thickness of the string.
The Formula
Where:
v=
Wave Speed (m/s)f=
Frequency (Hertz, Hz)=
Wavelength (meters, m)Example Calculation
A sound wave has a frequency of $440 , \text{Hz}$ (the note A4) and a wavelength of $0.78 , \text{meters}$ in air.
- Multiply Frequency by Wavelength: $440 \times 0.78 = 343.2 , \text{m/s}$.
This is the standard speed of sound at room temperature.