WEBVTT - Why can you hear the ocean in a seashell?

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<v Speaker 1>Welcome to Brainstuff from how stuff works dot com where

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<v Speaker 1>smart Happens. Hi Am Marshall Brain with today's question, why

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<v Speaker 1>can you hear the ocean when holding a seashell up

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<v Speaker 1>to your ear? Do you remember trying this as a kid,

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<v Speaker 1>holding one of the seashells you grabbed as a souvenir

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<v Speaker 1>up to your ear. It seems like no matter how

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<v Speaker 1>far away from the ocean you are, you can still

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<v Speaker 1>hold a seashell up to your ear and hear the

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<v Speaker 1>roar of the waves rolling on to the shore. The

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<v Speaker 1>best shells for producing this sound are the large spiral

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<v Speaker 1>conch cells. Some people have suggested that the sound you

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<v Speaker 1>hear from the seashell is the echoing of your blood

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<v Speaker 1>rushing through the blood vessels of your ear. That is

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<v Speaker 1>not the case. If that were true, then the sound

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<v Speaker 1>would intensify after exercising, since your blood races faster after exercising. However,

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<v Speaker 1>the sound is the same even after exercising. Others say

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<v Speaker 1>that the wooshing sound inside the shell is generated by

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<v Speaker 1>air flowing through the shell. Air flowing through the shell

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<v Speaker 1>and out creates a noise. You'll notice that the sound

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<v Speaker 1>is louder when you lift the shell slightly away from

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<v Speaker 1>your ear than it is when the shell is right

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<v Speaker 1>up next to your head. However, this theory doesn't hold

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<v Speaker 1>true in a soundproof room. In a soundproof room, there's

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<v Speaker 1>still air, but when you hold the seashell to your ear,

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<v Speaker 1>there's no sound. The most likely explanation for the wave

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<v Speaker 1>like noise is ambient noise from around you. The seashell

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<v Speaker 1>that you're holding just slightly above your ear captures this noise,

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<v Speaker 1>which resonates inside the shell. The size and shape of

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<v Speaker 1>the shell therefore has some effect on the sound you hear.

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<v Speaker 1>Different shells sound different because different shells accentuate different frequencies.

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<v Speaker 1>You don't even need a seashell to hear the noise.

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<v Speaker 1>You can produce the same ocean sound using an empty cup,

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<v Speaker 1>or even by cupping your hand over your own ear.

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<v Speaker 1>Go ahead and try it and vary the distance at

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<v Speaker 1>which you place the cup near your ear. The level

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<v Speaker 1>of the sound will vary depending on the angle and

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<v Speaker 1>distance the cup is from your ear. Noise from outside

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<v Speaker 1>the shell can change the intensity of the sound you

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<v Speaker 1>hear inside the shell. You can look at the shell

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<v Speaker 1>as a resonating chamber. When the sound from outside enters

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<v Speaker 1>the shell, it bounces around, thus creating an audible noise.

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<v Speaker 1>So the louder the environment you're in, the louder the

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<v Speaker 1>ocean like sound will be for more illness and thousands

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<v Speaker 1>of other topics. Is that how stuff works dot Com

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