Making Thunder Clouds
Name: Owen D.
What makes a thunder cloud and how do they make the noise?
Thunder-clouds are just another kind of storm-cloud. They do not make noise. In fact, clouds
cannot make noise because clouds are just bunches of very, very, small water drops kind of
floating around in the air. The drops are too small to see, but when enough of them are
gathered together, they make a cloud you can see. The noise you hear from a thunder-cloud
is the sound made by lightning that is happening in the storm.
Thunder clouds grow from smaller cumulus clouds when the weather
conditions are just right. Thunder is heard after a lightning strike.
Sometimes you cannot see the lightning, because of rain or some other
obstruction. And lightning is caused by the raindrops rubbing against each
other and water vapor in the clouds, and creating a big spark.
A thunder cloud is one that is large enough to produce lightning.
The most recent evidence (just this year) suggests that the noise of thunder is produced
by the splitting of air molecules (nitrogen and oxygen mostly) into atoms by lightning
energy (an explosion much like an atomic bomb). This is a new idea; it was thought before
that the sound of thunder was produced by the heating and rapid expansion of the air as
the lightning went through it.
David R. Cook
Atmospheric Research Section
Environmental Research Division
Argonne National Laboratory
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Update: June 2012