WEBVTT - What is a decibel, and how is it measured?

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

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<v Speaker 1>Brain with today's question. What is a decibel and how

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<v Speaker 1>is it measured? The decibel, abbreviated dB, is the unit

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<v Speaker 1>used to measure the intensity of a sound. The decibel

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<v Speaker 1>scale is a little odd because the human ear is

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<v Speaker 1>incredibly sensitive. Your ears can hear everything from your fingertip

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<v Speaker 1>lightly brushing over your skin to a loud jet engine.

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<v Speaker 1>In terms of power, the sound of the jet engine

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<v Speaker 1>is about one trillion times more powerful than the smallest

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<v Speaker 1>audible sound. That's a huge difference on the decibel scale.

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<v Speaker 1>The smallest audible sound near total silence is zero dB.

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<v Speaker 1>A sound ten times more powerful as ten dB. A

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<v Speaker 1>sound a hundred times more powerful is twenty d B.

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<v Speaker 1>A sound a thousand times more powerful than total silence

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<v Speaker 1>is thirty d B. Here are some common sounds and

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<v Speaker 1>their decibel ratings. A whisper is about fiften dB. Normal

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<v Speaker 1>conversation is around sixty d B. A lawnmower is up

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<v Speaker 1>near ninety. A car horn is a hundred dB, a

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<v Speaker 1>rock concert or a jet engine is a hundred and

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<v Speaker 1>twenty d B, and a gunshot or a firecracker is

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<v Speaker 1>around a hundred and forty d B. These are the

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<v Speaker 1>levels when standing near the source of the sound. You

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<v Speaker 1>know from your own experience that distance affects the intensity

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<v Speaker 1>of sound. If you're far away, the power is greatly diminished.

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<v Speaker 1>Any sound above eight five dB can cause hearing loss,

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<v Speaker 1>and the loss is related both to the power of

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<v Speaker 1>the sound as well as the length of exposure. Sure

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<v Speaker 1>you know that you're listening to an eight five dB

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<v Speaker 1>sound If you have to raise your voice to be

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<v Speaker 1>heard by somebody else, eight hours of nine d dB

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<v Speaker 1>sound can cause damage to your ears. Any exposure to

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<v Speaker 1>a hundred and forty dB sound causes immediate damage and

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<v Speaker 1>may cause actual pain. Do you have any ideas or

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