JOAN CARTAN-HANSEN, HOST: Simple machines are tools that help us work.

But how?

Join me as I go to the Discovery Center of Idaho to do some simple machine experiments.

[MUSIC] CARTAN-HANSEN: The six simple machines are the inclined plane, the pulley, the lever, the wheel and axle, the wedge, and the screw.

If you want to see how you use a simple machine, let's start with probably the oldest simple machine.

WOODY SOBI, DISCOVERY CENTER OF IDAHO: We're going to get started with the lever, a very fun one.

And what we have here is a balancing beam, which acts as a lever.

We have the fulcrum, the pivot point, right there in the middle.

And what we're going to do is we're going to start with a simple experiment.

I'm going to take this one weight, and I place it right here on the fifth peg out.

And I'm going to ask you to take one peg and see if you can place it on your side to balance it out.

Excellent.

So, by placing that one on the fifth peg, we can see that both sides are now balanced.

The same force is pushing down on both sides.

Now what I'm going to do is I'm going to change it around a little bit and I'm going to take a second weight and I'm going to place this on the same peg on my side.

But you don't have a second peg.

So how do you balance this with only one weight?

CARTAN-HANSEN: Okay, well, I think it involves math, but I think if I do this, it should balance.

SOBI: Excellent.

It certainly does involve math, and we've got it balanced there.

So, we have two weights at five, and we have one weight at 10.

So those two are going to be the same force pushing down on both sides of our lever.

So, what we can see here is you can have a small force pushing down further away equals a large force pushing down closer in.

And that's really the power of levers.

So now what we're going to do is we're going to try using that same idea of the levers again this time on a larger lever.

And we're going to try to use that concept of small forces further out, lifting larger forces.

And what we're going to do is we're going to try and lift Hannah off the ground.

So, we have our volunteer, Hannah here, CARTAN-HANSEN: Thank you for joining us.

SOBI: And we're going to go ahead and have her stand on the end of the ... CARTAN-HANSEN: I'll help you.

SOBI: the beam right there.

Excellent.

And when you're standing on that, I'm going to try to push down here and by pushing down on it, I can't lift you because the force is too much.

I'd have to put all my weight on it.

But what we're going to have you do is step back and now we're going to move the pivot point, the fulcrum here.

We're going to slide it out further and this time we’ll have you go ahead and stand on that again.

And now, because we have the difference in length, we're going to have a small force over here lifting you right up off the ground.

CARTAN-HANSEN: Voila.

We're going to move on to our next simple machine.

It's the pulley.

Tell us about it.

SOBI: Excellent.

And so, the pulley allows you to redirect forces, but it also allows you to multiply forces by using multiple pulleys together.

So, what we have is the first one is just a single pulley, and by pulling on this, you can lift the bowling ball, but you have to lift the entire weight of the bowling ball, and you get no mechanical advantage.

From here, we can move on to two pullies, which will give us some mechanical advantage.

So, move this over.

And now when we pull on this rope, we're going to be getting the mechanical advantage, so it'll be easier to pull, but we'll have to pull it much further in order to lift the bowling ball the same distance.

Then what we can do is we can try going over to our final pulley, which actually has four pulleys on it and is much easier to lift, but as a result you have to pull the pullies much, much farther.

So, with this one, you can start up and you just keep pulling and pulling and pulling before you get the bowling ball all the way to the top.

CARTAN-HANSEN: So, it takes less force when you have more pulleys.

So, it makes the work easier.

SOBI: It makes it much easier, but you have to do it over a much longer distance.

CARTAN-HANSEN: You know, I have a friend, George, who's going on a trip, but he's too heavy for me to move.

Can you help me?

SOBI: Well, I think we could certainly use some of these pulleys to help out.

Which one do you want to try?

CARTAN-HANSEN: Let's try the four-pulley system.

SOBI: Seems like a good idea.

Let's see if it works.

[MUSIC] CARTAN-HANSEN: And there we go.

SOBI: Alright, CARTAN-HANSEN: And I'm using another simple machine, the wheel and axle to help move George out of here.

Thank you so much for your demonstrations.

SOBI: Certainly.

I'm glad you could make it.

CARTAN-HANSEN: If you want to learn more about simple machines, check out the Science Trek website.

You'll find it at ScienceTrek.org.

[MUSIC] ANNOUNCER: Presentation of Science Trek on Idaho Public Television is made possible through the generous support of the Laura Moore Cunningham Foundation, committed to fulfilling the Moore and Bettis Family legacy of building the great state of Idaho; by the Idaho National Laboratory, mentoring talent and finding solutions for energy and security challenges; by the Friends of Idaho Public Television; and by the Corporation for Public Broadcasting.