Key Concepts: Speed of Sound

Speed of Sound

• In air at 20°C: approximately 343 m/s.
• Faster in liquids (~1,500 m/s in water) and fastest in solids (~5,000 m/s in steel).
• Sound travels faster in denser, stiffer media.

Factors Affecting Speed

• Temperature: Speed increases with temperature. v ≈ 331 + 0.6T (T in °C).
• Medium: Solids > liquids > gases (generally).
• Humidity: Moist air carries sound slightly faster than dry air.

The Wave Equation for Sound

• v = fλ applies. If frequency increases, wavelength decreases (for a given medium).
• When sound enters a different medium, speed and wavelength change, but frequency stays the same.