🦾 Hydraulic Robot Arm

🔊Let's build a robot arm that moves with water power!

⏱️ 2 hours💲 about $8●●●Grades 5th–8th🦾 Machines

• ✂️ Sharp! A grown-up does this part.
• 👶 Small parts! Keep them away from little brothers and sisters.
• 💧 Water
• 🧽 A bit messy

Gather first

• Flat cardboard · a cereal box or two
• 2 big plastic syringes (no needles)
• Clear tubing that fits the syringes · about an arm's length
• Paper fasteners (brads) · 3
• A tub of water
• A shoebox · 1, for the base
• 🔪 A box cutter 👋 grown-up
• 🍢 A wooden skewer 👋 grown-up
• 🩹 Tape

📖 Read it first: The Wheel at Hollow Creek

The big idea: Push water into one syringe and it pushes the other, because water won't squash.