Cardboard Hydraulic Syringe Robotic Claw

60 mins Ages 7-9 Indoor

An engaging, screen-free learning activity that builds real-world creativity and critical thinking for kids aged 7 to 9.

Materials Needed

  • • 10ml needleless plastic syringes (2 units)
  • • Clear flexible PVC or aquarium tubing (inner diameter to fit syringe tip) (30 cm)
  • • Corrugated cardboard scraps (2 panels)
  • • Brass paper fasteners (split pins) (4 units)
  • • Hot glue or duct tape (1 set)
  • • Water colored with 1 drop of food dye (1 cup)

Pro Tips

  • → Purge all air bubbles from the tubing and syringes; air compresses, causing squishy, unresponsive hydraulic movement.
  • → Tint the hydraulic water with food coloring so your child can track fluid transmission between pistons.
  • → Use split brass brads as smooth pivot hinges for the cardboard scissor-arm mechanism.

Safety First

Ensure syringes are needle-free medical/craft plastic units. Wipe water spills promptly.

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Step-by-Step Instructions

1

Step 1

Cut two matching cardboard claw jaws and join them at a central pivot using a brass split brad.

2

Step 2

Submerge a 10ml syringe in water, draw it full, connect flexible tubing underwater, and clear all air bubbles.

3

Step 3

Connect the second syringe to the other end of the water-filled tube to form a closed hydraulic circuit.

4

Step 4

Mount the slave syringe plunger to the cardboard claw and depress the master syringe to watch the claw grip and release small items.

What they are learning

Pascal’s Principle of fluid transmission Incompressible hydraulic work conversion Mechanical linkage kinematics