Speaker 1: Welcome to Brainstuff from how stuff works dot com where
Speaker 1: smart Happens. Hi Am Marshall Brain with today's question, why
Speaker 1: can you hear the ocean when holding a seashell up
Speaker 1: to your ear? Do you remember trying this as a kid,
Speaker 1: holding one of the seashells you grabbed as a souvenir
Speaker 1: up to your ear. It seems like no matter how
Speaker 1: far away from the ocean you are, you can still
Speaker 1: hold a seashell up to your ear and hear the
Speaker 1: roar of the waves rolling on to the shore. The
Speaker 1: best shells for producing this sound are the large spiral
Speaker 1: conch cells. Some people have suggested that the sound you
Speaker 1: hear from the seashell is the echoing of your blood
Speaker 1: rushing through the blood vessels of your ear. That is
Speaker 1: not the case. If that were true, then the sound
Speaker 1: would intensify after exercising, since your blood races faster after exercising. However,
Speaker 1: the sound is the same even after exercising. Others say
Speaker 1: that the wooshing sound inside the shell is generated by
Speaker 1: air flowing through the shell. Air flowing through the shell
Speaker 1: and out creates a noise. You'll notice that the sound
Speaker 1: is louder when you lift the shell slightly away from
Speaker 1: your ear than it is when the shell is right
Speaker 1: up next to your head. However, this theory doesn't hold
Speaker 1: true in a soundproof room. In a soundproof room, there's
Speaker 1: still air, but when you hold the seashell to your ear,
Speaker 1: there's no sound. The most likely explanation for the wave
Speaker 1: like noise is ambient noise from around you. The seashell
Speaker 1: that you're holding just slightly above your ear captures this noise,
Speaker 1: which resonates inside the shell. The size and shape of
Speaker 1: the shell therefore has some effect on the sound you hear.
Speaker 1: Different shells sound different because different shells accentuate different frequencies.
Speaker 1: You don't even need a seashell to hear the noise.
Speaker 1: You can produce the same ocean sound using an empty cup,
Speaker 1: or even by cupping your hand over your own ear.
Speaker 1: Go ahead and try it and vary the distance at
Speaker 1: which you place the cup near your ear. The level
Speaker 1: of the sound will vary depending on the angle and
Speaker 1: distance the cup is from your ear. Noise from outside
Speaker 1: the shell can change the intensity of the sound you
Speaker 1: hear inside the shell. You can look at the shell
Speaker 1: as a resonating chamber. When the sound from outside enters
Speaker 1: the shell, it bounces around, thus creating an audible noise.
Speaker 1: So the louder the environment you're in, the louder the
Speaker 1: ocean like sound will be for more illness and thousands
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