Pulleys

A pulley is a wheel with a groove in it for a rope. When you pull one end of the rope, the other end goes up. Pulleys make it easier to lift heavy objects. They have been used for thousands of years.

How Pulleys Work

A single pulley changes the direction of the force. You can pull down to make something go up. This is easier because you can use your body weight to help. Adding more pulleys makes lifting even easier. With two pulleys, you only need half as much strength.

Where We See Pulleys

Pulleys are used in many places. Flagpoles use pulleys to raise and lower the flag. Window blinds use small pulleys to open and close. Big cranes at building sites use pulleys to lift heavy steel beams. Sailboats use pulleys to raise their sails.

Fun Facts

• Elevators use pulleys to move people up and down tall buildings.
• A set of pulleys working together is called a block and tackle.
• Ancient Greeks used pulleys to lift heavy stones for their buildings.

Did You Know?

Using many pulleys together, one person can lift something that weighs as much as a car.