Kaleidoscope Optics

The kaleidoscope was invented in 1816 by Sir David Brewster, a Scottish physicist and Christian minister. The origin of the word kaleidoscope speaks to the splendid images. Kaleidoscope finds its roots in the Greek word kalos meaning "beautiful", the Indo-european eidos that means "form", and scope that is Greek for "to see".

Kaleidoscopes are made with two or more mirrors. Light reflecting between these mirrors produces multiple virtual images of stunning beauty.

The multiple image photographs on this page were

created by a 60°-60°-60° kaleidoscope with dried flower petals and leaves as the original objects.

We will focus on a kaleidoscope of this type. Three front-surface mirrors are set together to form an equilateral triangle, as shown in the figure below.

Real object.

Standard, household mirrors have a protective layer, such as glass, covering the reflective surface. First- or front-surface mirrors do not have a heavy protective surface. Additionally, the elimination of a protective surface simplifies the optics!

Light rays are assumed to bounce off the mirrors like a ball bounces off a hard surface.

Formally stated, "the angle of incidence equals the angle of reflection."

Images are located where the outgoing light rays appear to intersect.

July 2004 -Dr. Jen

Updated March 2005

Go to first reflection images.

Interior of 60-60-60 kaleidoscope. View inside a 60-60-60 kaleidoscope.

Shop for a kaleidoscope.