Make a DIY Claw

Materials you'll need

• 5 flexible straws (assorted colors)
• String or yarn
• Tape
• Marker
• Scissors

 

Step-by-step tutorial

Step 1: Lay all 5 straws flat on a surface. Use a marker to make a dot on each straw at the same point along its length — this marks where the joint will go.

Step 2: Cut each straw diagonally at the mark. A diagonal cut creates a V-shaped notch that lets the straw bend like a knuckle without snapping all the way through.

Step 3: Thread a piece of string up through the bottom of each straw so it exits at the cut. Tape the string to the straw just above the cut so it's anchored at the joint. Leave a long tail of string hanging out the bottom of each straw.

Step 4: Line up all five straws side by side and tape them together firmly at the bottom (handle) end to bundle them into one claw.

Step 5: Hold the taped end in one hand and pull all the strings together with the other — watch the straw fingers curl and close! Point the claw at an object and pull to grab it.

Learn more

This claw works the same way your actual fingers do. Inside your hand, long cables called tendons run from your forearm muscles all the way through your fingers. When those muscles contract, they pull on the tendons, which bend your finger joints — just like pulling the strings bends the straw joints. The diagonal cut in each straw acts like a knuckle, giving each "finger" a hinge point to flex around. Engineers call this a tendon-driven mechanism, and it's the same principle behind robotic hands and prosthetic fingers.