How Does a Kaleidoscope Work?

kaleidoscope-work Credit: fdecomite/CC-BY-2.0

A kaleidoscope works by reflecting light that bumps into a reflective surface such as a mirror. It has two or more mirrors placed at an angle to each other. The mirror assembly is surrounded by a case, with an eyehole at one end of the mirrors and a collection of objects at the other end.

These reflective surfaces typically form a triangle or V shape. When a kaleidoscope is turned, the pieces move and a different design can be seen. The reflections bounce back and forth inside the tube creating various images. What a person sees when looking through the eyehole is never exactly the same twice. Typically, kaleidoscopes have a collection of glass pieces, beads and buttons that form intricate and attractive designs. This is partly because of symmetry. All repeated images are symmetrical in relation to the image beside them. A precise combination of reflective surfaces results in precise symmetrical images.

The objects inside a kaleidoscope move, this is why after rotating or shaking the container, the objects never have the same arrangement a second time. It is also not possible to have two completely identical designs. Different patterns are formed as object reflections move from one side to another and merge with others. Three or more mirrors create a design with geometric and more intricate patterns and endless reflections. For example, a kaleidoscope with three mirrors creates complex triangular reflections.