Do you remember trying this as a kid -- Holding one of the seashells you grabbed as a souvenir up to your ear? It seems like no matter how far away from the ocean you are, you can still hold a seashell up to your ear and hear the roar of the waves rolling onto the shore. The best shells for producing this sound are the large, spiral conch shells.
你是否记得在小的时候，你把那个拾来做纪念的海螺贴到耳边，不管你离大海多远，似乎还是能从海螺里听见海浪冲刷沙滩的响声。最适合拿来“听海”的，莫过于大只的海螺了。

Some people have suggested that the sound you hear from the seashell is the echoing of your blood rushing through the blood vessels of your ear. That is not the case. If that were true, then the sound would intensify after exercising, since your blood races faster after exercising. However, the sound is the same even after exercising.
有人认为从海螺里听见的这种声音是耳朵附近的血管里血液流动的回声。如果这种说法是对的，那么在运动过后，这种声音应该会变得更响，因为这时人体的血液循环加快了。但事实并非如此，也就说明之前的说法站不住脚。
Others say that the whooshing sound inside the shell is generated by air flowing through the shell - air flowing through the shell and out creates a noise. You'll notice that the sound is louder when you lift the shell slightly away from your ear than it is when the shell is right against your head. However, this theory doesn't hold true in a soundproof room. In a soundproof room, there is still air, but when you hold the seashell to your ear, there's no sound.
另有人认为，这种嗖嗖的声响是由海螺里的空气流动产生。如果你把海螺从耳边稍稍地挪开一点，你会发现这时的声响要比海螺贴在耳旁的时候来的更大一些。不过，这个理论在同样被证明是错误的。在一件隔音的房间里，空气照常流动，但此时把海螺贴在耳边并不能听到声响。
The most likely explanation for the wave-like noise is ambient noise from around you. The seashell that you are holding just slightly above your ear captures this noise, which resonates inside the shell. The size and shape of the shell therefore has some effect on the sound you hear. Different shells sound different because different shells accentuate different frequencies. You don't even need the seashell to hear the noise. You can produce the same "ocean" sound using an empty cup or even by cupping your hand over your ear. Go ahead and try it and vary the distance at which you place the cup near your ear. The level of the sound will vary depending on the angle and distance the cup is from your ear.
最可信的解释是：这种涛声似的的声音其实是听者周遭环境中的声响。当你把海螺从耳边稍稍挪开的时候，海螺捕捉到了背景的声响，并且在螺内产生了共振。海螺的形状和尺寸会影响到你听到的声音，不同的海螺听上去会不一样，因为它们发生共振的频率各不相同。其实为了听到这种声响，你用不着专门找一只海螺来。拿一只空杯子，或者握一只空心拳头贴在耳朵上，你就能造出这种“海的声音”。快去试试看，也可以试试稍稍调整空杯子离你耳朵的距离，声音的大小会随着杯子距离和角度的改变而改变。
Noise from outside the shell also can change the intensity of the sound you hear inside the shell. You can look at the shell as a resonating chamber. When sound from outside enters the shell, it bounces around, thus creating an audible noise. So, the louder the environment you are in, the louder the ocean-like sound will be.
外界的声响也会影响到你从海螺里听到声响的强弱，你可以把螺体看做一个共鸣腔，外界的声波传到螺内之后会在里面来回反弹，从而形成了听得见的声响。所以越是在声响大的环境里，“海浪”的声音也越清晰。