Formation and Structure of Cyclones/Hurricanes Video Lecture | Class 7 Oxford Science: Chapter Notes, Worksheets & Tests

It’s summer where Squeaks and I live, which
means we’ve had a lot of thunderstorms lately!
Summer thunderstorms usually have rain, thunder,
and lightning, and sometimes strong, gusty
winds.
Sometimes the power even goes out!
Good thing Squeaks and I keep a flashlight
here just in case!
But some areas of the world experience a really
extreme kind of storm: a hurricane.
Hurricanes are big, powerful storms that have
strong winds.
And I mean strong— In order to be considered
a hurricane, a storm’s winds have to be
blowing faster than 119 kilometers an hour.
That’s faster than a car zooming down the
highway!
Sometimes you’ll also hear this kind of
storm called a cyclone or a typhoon, but they’re
just different names for the same thing.
From outer space, many hurricanes look like
this: big, swirling storms that have a really
cool shape.
[Squeaks squeaks]
That’s right, Squeaks, this hurricane looks
kind of like a circle!
The clouds wind around a space in the center
of the hurricane, called the eye.
It even sort of looks like an eyeball!
Now, a hurricane’s shape is pretty cool,
but it’s not the only thing that’s special
about this kind of storm.
Everything has to be just right for a hurricane
to form.
It’s kind of like a puzzle.
All of the pieces have to be there, and have
to fit together in exactly the right way,
or a hurricane won’t form.
The first piece of the hurricane puzzle is
warm ocean water.
The water has to be at least 27 degrees Celsius,
or about as warm as a swimming pool, for a
hurricane to form.
The warm water causes the air above it to
warm up and rise high into the sky
The warm air very humid, which means that
there’s a lot of water in it.
This warm, moist air rises high into the sky
from the warm water below.
As the air rises into the sky, other air rushes
in to take its place.
The air that rushes in gets warm and humid,
too, and then it rises high into the sky as
well.
As the air rises, it cools, and clouds start
to form—lots of them!
High in the sky is also where we find the
second thing that’s important for making
a hurricane: wind.
And not just any wind.
The wind that helps make a hurricane has to
be calm and steady.
It can’t be the kind of wind that blows
really hard for a moment or two, then calms
down again.
If there are sudden gusts like that, the storm
can get blown apart, like how a candle gets
blown out.
But if there’s warm, damp air along with
those steady winds, and it stays like that
for a few days, the rest of the pieces that
make up a hurricane fall into place.
The steady winds push the growing storm over
the ocean, and the warm water gives the storm
energy.
It causes more air to rise, more clouds to
form, and the winds inside the hurricane to
become stronger.
In fact, the only place that it’s not very
windy is the hurricane’s eye.
It’s actually very calm in the eye — even
though it’s right in the middle of the storm!
As it grows, the hurricane also starts to
turn.
It spins around, with the eye in the center,
kind of like a top.
As long as hurricanes have that warm air for
fuel, they can keep going … and keep growing!
But when they reach land, or pass over cooler
water, they lose their warm air, so they start
to fall apart.
Hurricanes usually leave behind a lot of rain,
though.
Sometimes the rain can last for days!
They also can can push a lot of ocean water
onto the shore, which can cause floods.
But people can prepare for hurricanes, especially
if they know when they’re going to happen.
For example, most hurricanes near North America
happen between May and November every year,
because that’s when the different pieces
that make a hurricane fit together the best.
And scientists have lots of tools to try and
track hurricanes — they use what they know
about science to make really good guesses
about where they’ll pop up, where they’ll
go, how big they’ll be, and how long they’ll
last.
In places where hurricanes happen a lot, they
usually build buildings in special ways so
they won’t get damaged by the strong winds
or flooding water.
And if you live or go on vacation in a place
where hurricanes might happen, you can be
prepared, too!
You can talk to grownups about what you can
do if a hurricane happens.
That might mean like bringing in things from
outside to protect them from strong winds,
or it might mean helping to prepare a kit
with food and water, flashlights, and a radio.
b
Speaking of flashlights, I know mine could
use some new batteries.
C’mon, Squeaks, let’s go to the store.
Thanks for joining us for this episode of
SciShow Kids!
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