Scribble Bot

Students build a robot that draws on its own, using a plastic cup, markers, a small motor and a battery. They predict what kind of drawing it will make, then watch their robot shake and wiggle across the paper, leaving a path of scribbles. Along the way, they discover that a tiny piece of eraser on the motor makes it spin unevenly, and that this wobble creates the vibration that moves the robot. It's a hands-on lesson in circuits, vibration and engineering design, and one where every bot draws something different.