Welcome to Brainstuff from house stuff works dot com, where smart happens, brought to you by Visa. We all have things we like to think about. Online fraud shouldn't be one of them, because with every purchase, PISA prevents, detects, and resolves online fraud safe secure Visa. Hi, I'm Marshall Brain with today's question. What is a decibel and how is it measured? The decibel, abbreviated dB, is the unit
used to measure the intensity of a sound. The decibel scale is a little odd because the human ear is incredibly sensitive. Your ears can hear everything from your fingertip lightly brushing over your skin to a loud jet engine. In terms of power, the sound of the jet engine is about one trillion times more powerful than the smallest audible sound. That's a huge difference on the decibel scale. The smallest audible sound near total silence is zero dB.
A sound ten times more powerful as ten dB. A sound a hundred times more powerful is twenty d B. A sound a thousand times more powerful than total silence is thirty d B. Here are some common sounds and their decibel ratings. A whisper is about fiften dB. Normal conversation is around sixty d B. A lawnmower is up near ninety. A car horn is a hundred dB, a rock concert or a jet engine is a hundred and twenty d B, and a gunshot or a firecracker is around a hundred and forty d B. These are the
levels when standing near the source of the sound. You know from your own experience that distance affects the intensity of sound. If you're far away, the power is greatly diminished. Any sound above eight five dB can cause hearing loss, and the loss is related both to the power of the sound as well as the length of exposure. Sure you know that you're listening to an eight five dB sound If you have to raise your voice to be heard by somebody else, eight hours of nine d dB
sound can cause damage to your ears. Any exposure to a hundred and forty dB sound causes immediate damage and may cause actual pain. Do you have any ideas or suggestions for this podcast? If so, please send me an email at podcast at how stuff works dot com. For more on this and thousands of other topics, go to how stuff works dot com.