WEBVTT

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[music playing]

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kids: "Our World"!

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- Did you know that there
are machines all around us?

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When you think of a machine, you
may think of a big, loud device

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that makes work easy.

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Sure, a car is a machine,

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but inside of that machine are
all kinds of simple machines.

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You can find them in the park,
or even in your own home.

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But what is a simple machine,
anyway?

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- Hi, and thanks for popping by.

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I'm using a simple machine
to share popcorn with a friend.

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[upbeat music]

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Can you guess
which simple machine

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I used to make this contraption?

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I have an inclined plane,
a screw, a wedge,

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a wheel and axle, a pulley,
and a lever.

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If you guessed the screw,
you're correct.

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A simple machine is a tool
that can help you do work easier

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and more efficiently.

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Simple machines have
one to two parts.

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They can make a force stronger,
change the direction of a force,

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or change the speed of a force.

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The force you apply
is called the effort.

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The object you move
is called the load.

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There are two groups
of simple machines.

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One group is a lever.

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A lever is a straight bar

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that moves on a pivot
point called the fulcrum.

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It helps you to lift something.

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The object lifted is called
the load.

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The closer the object is
to the fulcrum,

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the less effort that's needed
to lift the object.

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A pulley is another type
of lever.

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It's made of a rope and a wheel.

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When you pull down on the rope,

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it changes the direction
of the force,

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causing the object
on the other side to rise.

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An example is a flagpole.

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You may have seen one
outside of a school.

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Another type of lever
is called a wheel and axle.

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It's made of a wheel attached
to a post called an axle.

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It also helps
to make work easier.

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I'm sure you can think of
lots of examples

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of wheel and axles
all around you.

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The second group
of simple machines

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are called inclined planes.

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They make work easier

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by reducing the amount of effort

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needed to move an object.

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A screw is an inclined plane
wrapped around a cylinder.

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It turns a turning force
into a vertical force.

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A wedge is made of two
inclined planes back to back,

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and we use it
to split objects apart.

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Simple machines
are all over our daily lives,

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like a seesaw,
flagpole,

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window blinds,
toy cars,

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office chairs, slide,
wheelchair ramp,

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jar lid, a lightbulb, a knife,

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or a shovel
or a wheelbarrow.

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Sometimes two simple machines
can be combined

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to create a compound machine.

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Take scissors.

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They are two wedges
and two levers.

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Together they help cut paper.

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As you can see, simple machines
really are all around us.

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- "Wedge" you look at that?

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Simple machines are "wheely"
all around us.

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But did you know that NASA
uses simple machines, too?

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- NASA uses simple machines
for many applications.

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For example,
like, a lunar crane

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is just a whole bunch
of simple machines put together

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to make our work
on the Moon easier.

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On the lunar crane,

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the lever,
as you can see, is here,

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and the fixed point
is on this joint,

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so you pull one side,
the other side goes up

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and it will pick up
your heavy objects.

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The pulley is used here

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to change directions
of this cable

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to allow this motor here
to pull the cable,

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and have it
to drive the forearm.

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And the wheel,
you see,

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is on the base
that allows the entire arm

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to rotate on this axis
along here.

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So we can rotate left and right.

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And the pulley allows us
to move the arms up and down.

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- So the next time
you're opening a set of blinds

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or using a pair of scissors,

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remember that you're using
the same tools that NASA uses

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to explore new places and
make work easier in our world.

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I'm Abby.
See you next time.

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kids: "Our World"!