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Message Pulleys

A simple machine is a mechanical device that changes the direction or magnitude of a force. A pulley is a simple machine made from a wheel and cord, used to re-direct force. Some pulley systems make work easier, allowing the use of less force to move an object.

The pulley's cord moves through the pulley to change the direction of a pulling force (e.g. lift heavy objects UP by pulling DOWN, move objects LEFT by pulling RIGHT). 

These activities are part of Science World's Big Science for Little Hands program Gadgets and Contraptions. They were developed and tested with Preschool and Kindergarten educators.

Objectives

  • Use ramps, pulleys, levers and pendulums.

  • Demonstrate how machines work.

Materials

  • Per Class or Group:
    2 chairs, tables or 2 door handles
    2 pulleys or rollers from a hardware store
    string or ribbon in 2 different colours
    clothes pins
    pieces of cardstock
    markers or crayons
    plastic cups
    paperclips
    coins, variety of small plastic animals or other toys

Key Questions

  • Can you send your message to the other end of the string?
  • Which direction do you pull the string to make the message move to the other end? Hint: Putting a small piece of coloured tape on the string may help children visualize which direction the string is moving.
  • Why do we pull the opposite direction to where we want our message to go?
  • How many coins can you send in the bucket? What happens if you put too many coins in?

What To Do

  1. Set up two pulleys, one at either side of a room (about 2-4 metres apart), and attach firmly to the chairs/tables/door handles.
  2. Tie together equal lengths of the 2 different coloured strings. Each piece of string must be long enough to reach between the two pulleys, with a bit extra. Thread the string from one pulley to the other and back, and then tie it to make a continuous loop.
  3. Draw messages and pictures on the card. Clip these to the string using the clothespins and work the pulley to send them to the other side of the room.
  4. Pull the opposite string (the one without the message attached) towards you, to make the message move away. Use the different coloured strings to emphasize this difference.
  5. Construct a bucket using the plastic cups and string. Use a paperclip to easily hook the bucket on and off the string. Send items across the message pulley in the bucket.

Extensions

  • Try creating a "landscape" for the children to send messages and items across e.g. over a river, between two castles.
  • Make a giant pulley system outside in the playground or between 2 trees. Use it to transfer bigger items.
  • Set up a vertical pulley to lift heavy objects up by pulling down.

Other Resources

Inventors of Tomorrow | Pulleys-Simple Machines for Kids