hydraulic bridge working model using syringes


In this project, we will create a working model of a hydraulic bridge using syringes, pipes, paper cups, and cardboard. The model will demonstrate how hydraulic systems can be used to raise and lower a bridge’s deck, simulating the operation of a real hydraulic drawbridge.

Materials Needed:

  1. Cardboard or foam board (for the bridge base)
  2. Two large medical syringes (without needles)
  3. Plastic tubing or straws
  4. Small paper cup (for bridge deck)
  5. Wooden dowels or sticks
  6. Hot glue gun or adhesive
  7. Water
  8. Optional: Food coloring for the hydraulic fluid

Step-by-Step Explanation:

  1. Constructing the Base:
    • Cut a piece of cardboard or foam board to create the base of the bridge.
    • Attach the two wooden dowels vertically to the base, on opposite sides. These will serve as the supports for the bridge deck.
  2. Creating the Bridge Deck:
    • Cut the paper cup in half horizontally to create the bridge deck.
    • Attach the cup’s open ends to the wooden dowels using adhesive. This creates a platform that can pivot.
  3. Setting Up the Hydraulic System:
    • Attach plastic tubing or straws to the nozzles of each syringe using adhesive or tape.
    • Insert the other ends of the tubing into the paper cup’s halves. These will serve as the pistons that raise and lower the bridge deck.
  4. Adding Hydraulic Fluid:
    • Fill one syringe with water. Add a drop of food coloring to the water if desired.
    • Push the plunger of the filled syringe, forcing water into the tubing and causing the bridge deck to rise.
  5. Demonstrating the Hydraulic System:
    • When you push down on one syringe’s plunger, water is forced through the tubing into the other syringe and raises the bridge deck.
    • When you pull up on the plunger of the raised syringe, water is drawn back, causing the bridge deck to lower.

Understanding the Science:

This project demonstrates the principles of hydraulic systems, where pressure applied to a confined fluid is transmitted equally in all directions. By using syringes, tubing, and water, you’ve created a simple version of how hydraulic systems operate, like those used in various engineering applications.


Through the hydraulic bridge working model, you’ve successfully demonstrated the fundamental concepts of hydraulic systems. This project showcases how pressure applied to a fluid in one part of the system can lead to controlled movement in another part.

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