Page 250 - (DK) I Can’t Believe It! 2

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Rotor blades move at
high speed, creating EAR-SPLITTING SOUND
a loud whirring noise
that can be heard up to
5 miles (8 km) away. At
100 ft (30 m) away, the
noise reaches 100 dB.

Humans can withstand 160 dB
before sound levels split eardrums.
A loud rock concert reaches 115 dB,
while a jet engine gets up to 140 dB.

Unlike an aircraft,
a helicopter can take off
without a runway, move
backward and sideways,
and turn in midair.

How loud

is an insect?

The African cicada (Brevisana

brevis) is the world’s
loudest insect, with

a call averaging
106.7 decibels (dB) at a
distance of 20 in (50 cm) away.

US_248-249_309600_Loud_Insect.indd 248 20/12/17 10:11 am