Make a Pulley:

• Empty spool of thread
• String/thread
• Pencils and pens

1) Grab several pens or pencils and tie them in a bunch with the string around the middle.2) Pull up on the string and lift the bunch.

3) Put a pencil or pen through a spool of thread and hold it up by the end. This would be easier if you had someone else hold the two ends of the pen/pencil for you.

5) Pull the loose end of the string down. Can you notice that the pencil bundle weighs less?

A simple pulley, like the one you made, should cut the weight in half.