Hello I am Jared, welcome to FunScienceDemos. There is a lot going on here but you cannot see it
because what we are going take a closer look at today is air and how air moves.
And we are going use
this set up to give you a better idea of
how wind works. So our setup is pretty
simple I have a container of soil that
I am heating up with these hot lights. I
have a container of ice water and I have
a nice clear tube connecting the two and
believe it or not, the air is moving
between these two containers I just
cannot see it because I cannot see the air.
Now to help us see the air we are going
use this really neat smoke stick that is
going generate some very safe and
harmless smoke to let us see what is
happening in the air. So let us jump in
to see if we can figure out how wind works.
Now through science we have
discovered that things heat up at different rates.
What does that mean? 
As the land heats up it heats up the air
above it and through science we have
discovered that when air heats up, it
spreads out, it expands, and it becomes
lighter and because it becomes lighter, it rises.
So you cannot see it but I have
all of this air that is being heated up
and rising. Now take a look over here the
water is cold
and through science we have discovered that when air gets colder, it gets denser,
it gets heavier, it compresses and that
means it sinks. So I have sinking cold
air over here I have rising warm air
over here and as that warm air rises
this sinking cold air sweeps in and
takes the spot of the rising warm air so
we actually have wind happening through
this tube but we cannot see it! Enter our
smoke stick. Now we are going introduce
some smoke and see if we can watch how
the air moves so here we go.
Bring my smoke stick in, get this
thing charged up and I am going put it
here and you should be able to see, yes!
I actually have a small current of wind
moving through my tube. You can see the
smoke just follow the wind current
through the tube and as it comes out
over here it is rising. That is how wind
works!
Now you might be thinking I was
shooting the smoke through this tube and
that is what was making it move so I am
going reverse it we are going try
shooting the smoke in this way and see
which way the wind is blowing so here
we go. Let us charged up our smoke stick,
get it fired up. I am going come in here and
try and shoot it you are going see I
cannot get it to go through the tube
because the air is moving through the
tube of this direction and it is pushing
it out
Even if I try shooting it in the tube
I am going against the wind and it is not working.
So remember what is happening the
warm air is rising it is lighter the cold
air is sinking and it is sweeping in to
take the spot of the rising warm air and
it is the wind current is going this way.
So let us see this one more time.
Warm air rises cold air sinks. It sweeps
in and takes the spot of the rising warm
air and we have wind and look at it move.
So think about what we have just shown you.
We have shown you that when we heat things unevenly.
That is what makes the air move.
Think about that as our planet.
Our planet has different areas being heated unevenly. The sun is really hot around the
equator and it is really cold around the
poles.
Well that uneven heating of the earth
makes the air move but also think about this.
Our planet is spinning and that
spinning also helps make the air move so
really two things are responsible for
wind the uneven heating and cooling of
the earth and the spinning of the earth
all help make that air move. And even
when we cannot see it that air is moving
all around us.
One more time...
We have wind. If you want to learn more about wind or weather check out our links in the video description.
Science is so cool,
even when we cannot see it.
Thanks for watching.
