Hi guys.
You know, today when you think of machines, we think of computers, we think of air conditioners,
we think of helicopters, we think of giant bulldozers.
But the reality is simple machines have been around for thousands of years.
Simple machines are things that make work easier.
What's a simple machine?
Think of a flag.
You don't climb the flagpole to put the flag up on the flagpole.
You pull the string down, right?
That's a pulley.
Think about it.
It made work easier.
You pull the string, the flag comes down.
You pull the string, the flag goes up.
It made the work easier.
I'm going to use a simple machine known as a wheel and axle.
Without wheels and axles, neither cars nor horses and their wagons would move.
The great part about this experiment is that you have a little challenge, which I'll tell
you about in a minute.
All I need is paper.
The paper is card stock.
Regular paper would be a little too flimsy and a little too thin.
You can get this at any supply store, card stock.
You can use white.
And then if you wanted to, you could actually color in a design, or you can use colored
paper.
My challenge is to create something known as a "puff mobile".
You're going to say to yourself, wait a minute, wheel and axle?
I don't have wheels at home.
But actually, you probably do.
See?
Do you know what this is?
It's a candy.
If you look at it, it looks like a wheel.
The beauty of science, in true science, is to build things and create things with things
that you have at home.
All I'm going to take is this candy and some card stock.
And check this out.
Straws.
If you go to the store, get an extra straw.
I'm going to show you how this will become the axle, this will become my wheel, and now
I'm going to create something known as, we’ll call it a puff mobile.
First, you want to think about how big you want your mobile to be.
This is a little too big for me, but the cool thing about science is that nobody gets to
tell you guys what to do.
You make your own decisions.
It's your way or the highway, so you get to design your car.
You get to make it pointy, you get to make it small, and you get to make it big.
So I'm going to take this and cut it in half.
Then what I'm going to do, you say to yourself, you know what?
Is that a good size?
If you don't think it's a good size, maybe you can make it a little smaller.
I'm going to make mine just a bit smaller.
You know what I'll do?
I'm going to fold it in half again.
Once you have the size of your car ready, you're now ready to add on your simple machine
known as the wheel and axle.
My straws.
I'm going to open it.
I'm going to take it.
I'm going to put it right at the top for now.
You could use Scotch tape, and you could use masking tape.
You could use Elmer's glue, though it will take a while for it to dry.
I think the tape makes it doesn’t look not too nice.
If you have a hot glue gun, I would prefer that.
Again, adult supervision is needed for a hot glue gun, because they are pretty warm.
But you could use Scotch Tape.
So, I’m going to take the hot glue gun, I’m just going to put a stream of hot glue
across the top here.
Then I'm going to take my straw.
Why I like hot glue guns is, ten seconds, nine, eight, seven, six, five, four, three,
two, one, and my axle is done.
Then I'm going to do the same thing on the other side.
If you don't have a bendable straw, it doesn't matter.
The size of the straw really doesn't matter.
I'm going to add another stream of glue, and I'm going to make it look exactly the same
on the other side.
Symmetry is important.
Ten seconds later, believe it or not, the glue has dried.
And now, you can see that something is starting to form here.
Now, your wheels, or whatever you want to call them.
It could be anything, a bottle cap that you can make an opening into.
Be creative.
I'm using hard candies.
There you go.
But there's a problem.
You don't want to get in a car where the wheels fall off.
The car will crash.
it doesn't seem too safe.
So, how do we get the wheel to stay in place?
I put that in here and take a piece of tape, regular tape.
I'm going to take the tape and wrap it around.
As I wrap it around, it creates like a little, little bolt.
You see?
Now it's thicker than the hole in the candy, and so your candy can't move.
And now, I'm just going to do the same thing four times.
Take the tape, and I'm going to wrap it.
What do I mean by wrap it?
I don't mean I'm going to start singing a rap song.
I'm just going to wrap it.
If you want, you can actually clip off the ends so that your car starts to look a little
cooler.
That's the design part, the design factor.
And check this out.
They actually rotate.
The wheel is on the axle.
This is my simple machine.
Now I'm going to take wheel three.
Now while I put the wheels on, what is your challenge?
You challenge is to create a machine that you are going to be able to move, simply by
using the force of air.
Everything on earth moves because of a force.
A force is either a push or a pull.
Gravity is a force.
Air is a force.
Your challenge is to create a machine that moves just by the force of air.
But here's the problem.
This is my puff mobile.
It's moving.
It moves.
But by being creative, and by creating walls, and by creating a back.
When you want to blow your car, it wants to hit something.
You see, air moves things.
Think of hurricanes.
Think of tornadoes.
Air, when it's moving, is wind.
A fast-moving wind can be scary.
It could pick up school buses.
But for today, it's not going to be scary.
We're going to try to direct the air from our mouth, hit a target on my puff mobile,
and get the puff mobile to move.
I don't need batteries.
Nothing cool, nothing expensive.
I already pre-made one.
Check this out.
If you have time, be creative.
Cotton balls I've just created using my extra paper.
I made a little cylinder.
Now, that can be my target.
Now I'm going to try to focus my breath, hit the target, and test my puff mobile to see
if it works.
Should we try it?
Let's try it.
Ready?
Let me just move this.
If you do, do it on the table and you break your wheel, you could always replace it.
Then you can think about forces.
Small force, strong force.
Think about the curtain that you have at home with the windows open.
Sometimes it moves very slowly.
That's a small force of wind.
Sometimes it moves very fast.
That's a strong force.
I'm going to start with a small force.
Let's see what happens.
Ready?
Small force, let's try it.
Now all four wheels rotated on its axle.
It's perfect.
Now, think about how you can change the force of air.
Breathe in more air, blow it out fast.
Blow it out even harder.
See how far you can get the car to go.
Let's try it.
Uh oh.
Hopefully those wheels didn't break.
Let's check it out.
And that's my puff mobile.