A pulley is a wheel with a rope around it. It  is also held by a hook.       It can pull cars and trucks. It can take people to  different  levels in an elevator, and it also can pull up the blinds for us. It pretty much makes life easier. It can even help us lift 10 times our own weight!

     Examples of what uses a pulley are cranes, blinds , elevators ,and tow trucks. Pulleys can be fun. One day when I was bored, I noticed how hard it was to pick up my big container of bubbles by hand. So I threw a rope over the swing set, and I tried to pick up the thing of bubbles and it was  easier! Why? Because now gravity was on my side and helping me lift as I was pulling down instead of picking up.

     Pulleys help us a lot! They make lifting things easier. They help make life easier. Because of pulleys, we don't have to walk up stairs because pulleys help move an elevator. It helps us with things such as a crane because it picks up really heavy things. Also, the more pulleys you have, the less effort you have to give to lift something.  The two pulley system shown on the left only takes half the effort to pull as a one pulley system. the four pulley system on the right only takes one quarter the effort to pull as a one pulley system.

     Here are some more examples of pulleys:

  boat                                   blinds              flags                original
                                                                                       pulley

Here are some links where you can learn even more:

Edheads Simple Machines Game

SIMPLE MACHINES LEARNING SITE

Dynamic Science

Bibliography:

http://en.wikipedia.org/wiki/Pulley