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How Loud Can a Person Shout?

There are a number of ear-splitting sounds on earth. A nearby jackhammer breaking up concrete can generate noise at an unpleasant level of 100 decibels. A crack of thunder can send sound waves to your ears at the 120-decibel level.

But what about the human voice? Elementary school teacher Annalisa Flanagan of Belfast, Northern Ireland, earned herself a place in Guinness World Records at a 1994 contest. To claim the world record, she (ironically) hollered “QUIET” so loudly that it registered at an astounding 121.7 decibels, which has the same head-ringing quality of a jet engine.

Flanagan has had her tonsils removed since then, so she is hesitant to try to replicate or better her record-setting shout. Her students rarely give her cause to raise her voice, but she’s not shy about shouting at the occasional hockey match.

Making a lot of noise:

  • Scientists say that the loudest sound on earth is a Saturn V rocket blasting off. It’s been measured at 204 decibels.

  • Sperm whales emit sounds during echolocation at a level of 174 dBA.

  • In 1883, at the moment when the volcanic island of Krakatoa blew itself to smithereens, the explosion could be heard thousands of miles away. Scientists think this is probably the loudest sound humans have ever accurately measured.

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    • According to "Guinness World Records," the loudest human shout reached 121.7 decibels.
      According to "Guinness World Records," the loudest human shout reached 121.7 decibels.