What Do We Need for a Thunderstorm?

Have you ever woken up in the middle of the night to a bright flash followed
by a loud BOOM?   It’s probably a thunderstorm! When I was little, I was
completely afraid of thunderstorms.  But, I’ve gotten older, I’ve learned how
thunderstorms work, and now they’re not as scary. We still need to be
careful around thunderstorms, though, and it’s not a good idea as a pilot to
fly in one!

Let’s see if we can figure out how those flashy storms work.

There are three things we need for a thunderstorm to form: unstable air, a
lifting force, and moisture.

The first thing is unstable air.  Warm air rises, and cold air sinks.  Which do
you think would make the air more unstable:  a layer of cold air above warm
air?  Or, a layer of warm air above cold air?  If you said the cold air above
warm air, you’re right!  Because warm air rises, when there’s cold air above,
it makes it very easy for that warm air to rise quickly, and so, it’s “unstable”.
The next thing is a lifting force.  While unstable air makes it easy for the air
to rise, we also need something like a mountain range, wind, or a front to
make sure that air rises rapidly.  

Finally, we need moisture.  The moisture is needed to form the clouds and
rain.  When we have all three of these things, voila!  We have a
thunderstorm!

There is always one thing that is associated with a thunderstorm.  Do you
know what it is?  Lightning!  When you drag your feet across the carpet, and
then touch the doorknob, what happens?  You get shocked!  This is because
of positive and negative electrical charges.  Lightning during a thunderstorm
works the same way.  With all the raindrops and hail stones moving around
in the cloud, some of them end up with positive charges and some end up
with negative charges.  Positive charges tend to gather at the top of the
clouds, and the negative tend to gather at the bottom of the clouds.  

You’ve heard of the saying “opposites attract”?  It’s true!  Positive charges
are attracted to negative charges.  So, if the negative charges are on the
bottom of the clouds, and there are positive charges on the ground, the
charges eventually connect with each other, and ZAP!  We get lightning!  
Lightning is really hot.  It can get up to 54,000 degrees Fahrenheit.  That’s
hotter than the surface of the Sun!  When the air gets heated up that fast,
there is a lot of energy, and the air expands.  When the air collapses back to
its original position, that’s what we hear as thunder.  

There is a way we can figure out how close a thunderstorm is too.  Once you
see a flash, count how many seconds until you hear the thunder.  Then,
divide those seconds by 2.  So, if you counted 12 seconds between the
lightning and thunder, then the lightning is 6 miles away! [12 / 2 = 6]

Remember, when you see lightning, or hear thunder, it’s best to get inside.  
Lightning strikes actually injure more people each year than tornadoes.

COOL LIGHTNING EXPERIMENT
    What You Need:
    -Balloon
    -Fluorescent Light Bulb

Turn off all the lights in the room.  Try to get it as dark as you can.  Rub the
balloon on your hair for several seconds, building up a good static charge.
Then, put the balloon close to the end of the light bulb.  You should see the
bulb light up briefly!  Just like a lightning strike!

What’s Happening?

When you rub the balloon against your hair, you’re giving that balloon a
static charge.  When you put it near the light bulb, that electrical charge
moves from the balloon to the light bulb and causes it to light up.  

Written by Erin Willison,
Education Coordinator at
Evergreen Aviation and Space Museum
Using aviation to entertain
and educate girls about
their limitless
opportunities...
Using aviation to entertain
and educate girls about
their limitless
opportunities...
Using aviation to entertain
and educate girls about
their limitless
opportunities...
TM
Email Erin!
Your name:
Your email address:
Your phone number:
Comments:
Using aviation to entertain
and educate girls about
their limitless
opportunities...
Using aviation to entertain
and educate girls about
their limitless
opportunities...
Using aviation to entertain
and educate girls about
their limitless
opportunities...
TM
Did you know:  
Thunderstorms can
occur during any season
and any time, but they
are most common
during the Spring and
Summer months during
the afternoon or
evening.  There are
about 1,800
thunderstorms that
occur across our planet
every day!