How Do You Make A Cardboard Whirligig?
Colonial kids would have put a button whirligig together on a rainy New England day to stave off boredom. Almost two centuries later, an astronomer and a physicist both became fascinated with a similar toy, called “the thaumatrope.” Both toys rely on what’s called “persistence of vision,” which is your eye’s tendency to keep an image for a split-second. You can build both toys and see how they work and how they are related. Glue the piece of paper onto the cardboard. Apply the glue liberally. Trace the yogurt lid onto the cardboard with a pencil. Lightly draw a line across the diameter of the circle. Cut out the cardboard circle. Punch two holes on the diameter line, about a quarter of an inch from the center. Decorate the front of the circle. Put any kind of design, such as a color wheel or a spiral on it. Feel free to decorate the back as well, you may want to cover it with a piece of paper as well for a cleaner surface. Cut a loop of string to about four feet in length. String one e
