How to Make a Block and Tackle in Scouts

People have used block-and-tackle systems for centuries to move heavy objects.

The block-and-tackle system uses mechanical advantage to lift heavy objects with little force. The block is a series of pulleys through which the rope --- the tackle --- passes. Each pulley increases the system's mechanical advantage, making lifting heavy objects easier. Setting up and explaining how the block-and-tackle system works and how it applies to everyday life can go toward the Engineering Merit Badge for a scout.

Things You'll Need

• 2-sheave pulley with hook
• 15 meters of rope
• Item to lift
• Single-sheave pulley with hook
• Extra pieces of rope

Instructions

1. Attach a 2-sheave pulley to a secure spot above the object to be lifted using the hook. If the object to be lifted is light enough, secure a rope above the item and hook the pulley onto the rope.

2. Tie one end of a rope directly to the item you wish to lift.

3. Run the free end of the rope up through one of the sheaves --- the wheels inside the pulley --- and down the other side.

4. Hook a single-sheave pulley to the weighted object with a hook. Use another piece of rope to tie the object to the pulley if necessary.

5. Run the free end of the long rope through the bottom of the single-sheave pulley.

6. Bring the free end of the long rope through the other sheave of the top pulley.

7. Pull on the free end of the rope to lift the object off the ground.

Tips & Warnings

• To lift heavier objects, add extra blocks to your system.

• The length of rope required to lift the object will differ based on the number of blocks used and the how high you wish to lift the object.

References

• Atlantic All Ships: Block & Tackle
• Mini Science: Compound Machines Science Projects Using Pulleys
• Boy Scouts of America: Engineering