Does sound travel faster in air or in water?

Does sound travel faster in air or in water?

• A. In Air
• B. In Water
• C. Equally fast
• D. It depends on temperature

Answer: (B)

The speed of sound depends on how stiff a medium is and how easy it is to compress. In a fluid, the speed scales with the square root of the bulk modulus divided by the density. Water has a much higher bulk modulus (it's much stiffer) than air, and even though it's denser, the ratio B/ρ in water gives a much larger sound speed. That’s why sound travels around 1500 m/s in water, compared with about 343 m/s in air at room temperature. Temperature does affect speeds in both media, but under normal conditions the faster transmission in water persists.

The speed of sound depends on how stiff a medium is and how easy it is to compress. In a fluid, the speed scales with the square root of the bulk modulus divided by the density. Water has a much higher bulk modulus (it's much stiffer) than air, and even though it's denser, the ratio B/ρ in water gives a much larger sound speed. That’s why sound travels around 1500 m/s in water, compared with about 343 m/s in air at room temperature. Temperature does affect speeds in both media, but under normal conditions the faster transmission in water persists.