Discover how pulleys make lifting easier by spreading out force and changing direction. This science extra explores simple machines in action breaking down how pulleys work and where we use them every ...

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.

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.