Explore the clever mechanics behind pulleys in Jiwi's Machines Episode 2. Discover how simple systems create powerful movements in this exciting Science Extra feature.

EXPLANATION: A pulley is one of the six simple machines. Single pulleys were part of simple cranes invented more than 3,000 years ago. A pulley consists of a wheel that is free to turn its center.

Mister C and the Science Crew learn about simple machines! This episode couldn’t get any more simple. Mister C and the Science Crew are learning about simple machines! We’ll be building a ...

With a simple pulley the force you must exert is equal to the weight of the load. With a compound pulley—two or more pulleys combined together—you can reduce the force required to lift the load.

Atwood's machine is the name of a device that looks like this: Also known as "two masses on a pulley". Surprisingly, this simple device comes up a lot in intro physics texts.