Simple Machines
The pulley is a simple machine used for moving heavy things such as a load of bricks.
A pulley works by a rope looped over a wheel. Attached to the end of the rope is a hook.
How to use the pulley
First, simply attach the hook to the thing or things you are lifting (or if you don't have a hook wrap the rope round the stuff you are lifting). Pull on the other end of the rope to lift the object from the ground into the air.
What Do Simple Mechanisms Do?
I have seen a pulley on a crane before it was lifting a load of bricks.
I have also seen a pulley on a flag before
Pulleys make it much easier to move something they also change the direction of a force.