Purposeful Pulleys

Lesson Plan - Get It!

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The man in the picture above is using a pulley to help him lift something heavy.

A pulley is a simple machine that does a job a single human being may not be able to do. Moving or lifting hefty objects can be too difficult for one person to do on their own, so they can use tools to help.

Tools are things that people use to perform specific jobs.

Simple machines are tools that are used to make a difficult task, such as moving a heavy object, easier. Simple machines can operate without a computer or electricity.

A pulley is straightforward. All you need is a wheel and a piece of rope looped around the wheel. The wheel needs to be secured in place — preferably a high place if you're trying to lift a heavy object — if it will work properly.

One end of the rope is fastened to the object you lift, and you pull on the other end. The rope glides over the wheel, which turns in the same direction. As the wheel turns, it helps reduce the amount of force needed to lift the object.

As you learn about the uses of pulleys, fill in the Graphic Organizer 2 Column Chart sheet found in Downloadable Resources in the right-hand sidebar. An example has been done for you.

Pulleys have been used to help people lift things for more than 3,000 years! People needed a way to move water from a river to their homes and heavy logs from the forest to where they were building their homes.

Another example of a pulley that you may have seen, or maybe even used, is a flag pole. In this instance, you can stand on the ground and move the flag far up into the air by pulling on the chain or rope.

If you have curtains or blinds in your house, that cord you pull that makes them move is looped over a wheel, which makes it a pulley!

Pulleys are pretty simple, but things can get complicated depending on their use. For example, some pulleys have multiple wheels.

Other pulleys use weights on the other side, called counterweights. An example of a pulley system that uses counterweights is an elevator.

There are thousands of uses for pulleys in your world.

• Can you think of any other uses for pulleys?

Check out the video below to understand how a pulley works and how the effort used to move a heavy load can be lessened with a pulley system.

In the Got It? section, put your knowledge to creative use as you write your own story!