Hey, I'm Nate from Design Squad.

We got in a question to the website from berl88, who wanted to know, "How do you make a pulley?"

A pulley is a way to use a wheel for lifting.

You just need two things: one is something round-- I'm going to use a roll of paper towels-- and something to put the round thing on so it can spin.

Now, I've got a broom handle.

The broom handle is going to function as the axle, which is the thing the pulley spins around, and my paper towel roll is going to be the pulley.

Now, the cool part about it is the word "roll" is actually quite important.

We like wheels on cars because instead of the car sliding along the ground, the wheel helps it roll along the ground.

So in the same way, instead of having a rope or string slide over the axle, it gets to roll over the pole.

Now, over this pulley, I could put a rope or a string and pull on one side and have it lift up the other side, or I could attach the broom handle to something I wanted to lift, attach the string above, and then pull up from the other side, which would make it roll up, and that would actually make it easier to lift.

Pulleys are everywhere because they're so useful.

They help make work easier by redirecting motion or loads.

I used a pulley when I made a cat feeder system to get food up to a cat that lives two floors above me.

The pulley helped me redirect the cat food.

When I pulled the string down, the food went up.

What other questions do you have about how things work or stuff about engineering?

Send them on in to the Design Squad website.