Question

Explain, why an under water explosion recorded by sonar is about 4.5 times faster than heard through air.

Answer 1

The sound from an under water explosion travels through water, where sound travels much faster than it does through air.

Using typical values, the speed of sound is about 1450 m/s in water and about 332 m/s in air.

Thus, the ratio is 1450 ÷ 332 ≈ 4.4, or about 4.5.

Water is much less compressible than air, so it transmits sound vibrations more rapidly.

The explosion itself is not faster; it is the sound wave travelling through water that reaches the sonar sooner.