[music playing]
kids: "Our World"!
- Did you know that there are machines all around us?
When you think of a machine, you may think of a big, loud device
that makes work easy.
Sure, a car is a machine,
but inside of that machine are all kinds of simple machines.
You can find them in the park, or even in your own home.
But what is a simple machine, anyway?
- Hi, and thanks for popping by.
I'm using a simple machine to share popcorn with a friend.
[upbeat music]
Can you guess which simple machine
I used to make this contraption?
I have an inclined plane, a screw, a wedge,
a wheel and axle, a pulley, and a lever.
If you guessed the screw, you're correct.
A simple machine is a tool that can help you do work easier
and more efficiently.
Simple machines have one to two parts.
They can make a force stronger, change the direction of a force,
or change the speed of a force.
The force you apply is called the effort.
The object you move is called the load.
There are two groups of simple machines.
One group is a lever.
A lever is a straight bar
that moves on a pivot point called the fulcrum.
It helps you to lift something.
The object lifted is called the load.
The closer the object is to the fulcrum,
the less effort that's needed to lift the object.
A pulley is another type of lever.
It's made of a rope and a wheel.
When you pull down on the rope,
it changes the direction of the force,
causing the object on the other side to rise.
An example is a flagpole.
You may have seen one outside of a school.
Another type of lever is called a wheel and axle.
It's made of a wheel attached to a post called an axle.
It also helps to make work easier.
I'm sure you can think of lots of examples
of wheel and axles all around you.
The second group of simple machines
are called inclined planes.
They make work easier
by reducing the amount of effort
needed to move an object.
A screw is an inclined plane wrapped around a cylinder.
It turns a turning force into a vertical force.
A wedge is made of two inclined planes back to back,
and we use it to split objects apart.
Simple machines are all over our daily lives,
like a seesaw, flagpole,
window blinds, toy cars,
office chairs, slide, wheelchair ramp,
jar lid, a lightbulb, a knife,
or a shovel or a wheelbarrow.
Sometimes two simple machines can be combined
to create a compound machine.
Take scissors.
They are two wedges and two levers.
Together they help cut paper.
As you can see, simple machines really are all around us.
- "Wedge" you look at that?
Simple machines are "wheely" all around us.
But did you know that NASA uses simple machines, too?
- NASA uses simple machines for many applications.
For example, like, a lunar crane
is just a whole bunch of simple machines put together
to make our work on the Moon easier.
On the lunar crane,
the lever, as you can see, is here,
and the fixed point is on this joint,
so you pull one side, the other side goes up
and it will pick up your heavy objects.
The pulley is used here
to change directions of this cable
to allow this motor here to pull the cable,
and have it to drive the forearm.
And the wheel, you see,
is on the base that allows the entire arm
to rotate on this axis along here.
So we can rotate left and right.
And the pulley allows us to move the arms up and down.
- So the next time you're opening a set of blinds
or using a pair of scissors,
remember that you're using the same tools that NASA uses
to explore new places and make work easier in our world.
I'm Abby. See you next time.
kids: "Our World"!