Rapunzel's Rescue Pulley Challenge

This fun, hands-on lesson allows Charlee to explore the simple machine of a pulley, inspired by the book 'Keep It Simple, Rapunzel!: The Fairy Tale Physics of Simple Machines'. Charlee will build a basic pulley system to understand how it helps lift objects, connecting physics concepts to a familiar fairy tale.

PDF

Rapunzel's Rescue Pulley!

Remember reading 'Keep It Simple, Rapunzel!' and learning about simple machines? Today, we're going to focus on one of those machines: the pulley! Just imagine trying to get something up a tall tower – a pulley could really help! Let's build one!

Project: Build a Simple Fixed Pulley

Time: 25-30 minutes

You Will Need:

  • An empty thread spool (or a small wheel with a groove)
  • String or strong twine (about 2-3 feet long)
  • A pencil or small wooden dowel that fits loosely through the spool's hole
  • Something stable to suspend the pulley from (like the edge of a sturdy table, a chair back, or a doorknob – ask for help finding a good spot!)
  • A small object to lift (like a small toy, a keychain, or a little bag with a few coins)
  • Tape (optional, to secure the pencil/dowel)

Let's Build! (Instructions for Charlee):

  1. Prepare the Object: Tie one end of your string securely around the small object you want to lift. This is your 'load'.
  2. Assemble the Pulley: Slide the pencil or dowel through the hole in the center of the spool. Make sure the spool can spin freely on the pencil/dowel. The spool is your pulley wheel!
  3. Mount the Pulley: Find a place to set up your pulley. You need to position the pencil/dowel so that the spool hangs downwards and can spin. You could:
    • Rest the ends of the pencil/dowel across the backs of two chairs placed close together.
    • Tape the ends of the pencil/dowel securely to the edge of a sturdy table so the spool hangs off the edge.
    • Have someone hold the ends of the pencil/dowel firmly.
    Make sure your setup is stable!
  4. Thread the Pulley: Drape the *other* end of the string (the one NOT tied to the object) over the top of the spool, letting it sit in the groove.
  5. Test Your Machine!: Gently pull DOWN on the free end of the string. What happens to your object? It should lift UP!

Think About It:

  • Was it easier to lift the object by pulling down on the string compared to lifting it straight up with your hand?
  • How did the pulley change the direction you needed to pull? (You pulled down, the object went up!)
  • How could Rapunzel or the Prince have used a pulley like this at the tower?

Great job, engineer! You've built a simple machine just like the ones discussed in the book!