What are the approximate speeds of sound in air at room temperature and in water?

What are the approximate speeds of sound in air at room temperature and in water?

• A. Air 343 m/s; Water 1000 m/s
• B. Air 360 m/s; Water 1500 m/s
• C. Air 343 m/s; Water 1482 m/s
• D. Air 300 m/s; Water 1482 m/s

Answer: (C)

Sound speed depends on how easily a medium can be compressed and how much inertia the particles have to move. The relation v ≈ sqrt(B/ρ) (where B is the bulk modulus and ρ is the density) captures this: a medium that is easy to compress or has low density yields a slower sound speed, while a stiff, dense medium yields a faster speed. For air at room temperature (about 20°C), the density is relatively low and the compressibility is such that sound travels at roughly 343 m/s. In water, the density is much higher and the liquid is quite stiff, so the ratio B/ρ is large and sound moves much faster—about 1482 m/s on average. So the values air ~343 m/s and water ~1482 m/s are the standard approximate speeds, matching the best answer. Other options mix speeds that don’t align with these well-established room-temperature values.

Sound speed depends on how easily a medium can be compressed and how much inertia the particles have to move. The relation v ≈ sqrt(B/ρ) (where B is the bulk modulus and ρ is the density) captures this: a medium that is easy to compress or has low density yields a slower sound speed, while a stiff, dense medium yields a faster speed.

For air at room temperature (about 20°C), the density is relatively low and the compressibility is such that sound travels at roughly 343 m/s. In water, the density is much higher and the liquid is quite stiff, so the ratio B/ρ is large and sound moves much faster—about 1482 m/s on average.

So the values air ~343 m/s and water ~1482 m/s are the standard approximate speeds, matching the best answer. Other options mix speeds that don’t align with these well-established room-temperature values.