十万个为什么·科学启蒙30篇（2）

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为什么声音在水中比在空气中传播得更快？

Sound travels as vibrations that move through particles in a medium like air or water.
Water molecules are packed much more tightly than air molecules, so energy transfers faster.
In air at 20°C, sound moves at about 343 meters per second.
In seawater, sound travels at approximately 1,500 meters per second—over four times faster.
Temperature, pressure, and salinity all affect how fast sound moves underwater.
Whales use low-frequency sounds to communicate across hundreds of kilometers in oceans.
Sonar devices send out sound pulses and measure echoes to map underwater terrain.
Unlike light, sound bends—or refracts—when moving between layers of different water temperatures.
This bending allows sound to travel long distances along ocean 'sound channels'.
That is why submarines can detect each other from far away using passive sonar.