Definitions

kaleidoscope

kaleidoscope

[kuh-lahy-duh-skohp]
kaleidoscope, optical instrument that uses mirrors to produce changing symmetrical patterns. Invented by the Scottish physicist Sir David Brewster in 1816, the device is usually a hand-held tube, a few inches to as much as twelve feet in length, and looks like a small telescope. At one end of the tube is an eyepiece; at the other end colored chips of glass are loosely sandwiched between two glass disks. Between the ends of the tube are two rectangular plane mirrors. The long edge of one of the two mirrors lies against the long edge of the other at an angle, their intersection lying close to the axis of the tube. The glass chips form patterns where they lie, and these patterns change as the chips fall into new positions when the tube rotates. Each pattern undergoes multiple reflections in the mirrors in such a way as to produce a resulting symmetrical pattern as seen through the eyepiece.

The world's largest kaleidoscope, located in Mt. Tremper, N.Y., is 64 ft (19.5 m) tall. There is no eyepiece; people stand inside the base to view the image, which is projected downward onto three reflective panels to produce a spherical cluster of 254 hexagonal facets that appears to be 50 feet across. For Expo 2005 in Aichi, Japan, a 130-ft-high (40-m) kaleidoscope was constructed in the three-sided Earth Tower; three enormous, oil-filled revolving disks filtered incoming light that was reflected by huge mirrors to produce a spherical image some 118 ft (36 m) in diameter; the image was viewed by standing inside the tower.

See C. Baker, Kaleidorama (1990); G. Newlin, Simple Kaleidoscopes: 24 Spectacular Scopes to Make (1996).

Optical device consisting of mirrors that reflect images of bits of coloured glass or other objects in a symmetrical geometric design through a viewer. The design may be changed endlessly by rotating the section containing the loose fragments. A simple kaleidoscope consists of two thin, wedge-shaped mirror strips touching along a common edge. The mirrors are enclosed in a tube with a viewing eyehole at one end. At the other end is a thin, flat box that can be rotated; it is made from two glass disks, the outer one ground to act as a diffusing screen. In this box are pieces of coloured glass, beads, etc. When the box is turned, the objects inside tumble into an arbitrary grouping, and when the diffusing screen is illuminated, the sixfold or eightfold multiplication creates a striking symmetrical pattern. The kaleidoscope was invented by Sir David Brewster circa 1816.

Learn more about kaleidoscope with a free trial on Britannica.com.

A kaleidoscope is a tube of mirrors containing loose colored beads, pebbles or other small colored objects. The viewer looks in one end and light enters the other end, reflecting off the mirrors. Typically there are two rectangular lengthwise mirrors. Setting of the mirrors at 45° creates eight duplicate images of the objects, six at 60°, and four at 90°. As the tube is rotated, the tumbling of the colored objects presents the viewer with varying colors and patterns. Any arbitrary pattern of objects shows up as a beautiful symmetric pattern because of the reflections in the mirrors. A two-mirror model yields a pattern or patterns isolated against a solid black background, while a three-mirror (closed triangle) model yields a pattern that fills the entire field.

For a 2D symmetry group, a kaleidoscopic point is a point of intersection of two or more lines of reflection symmetry. In the case of a discrete group the angle between consecutive lines is 180°/n for an integer n≥2. At this point there are n lines of reflection symmetry, and the point is a center of n-fold rotational symmetry. See also symmetry combinations. Modern kaleidoscopes are made of brass tubes, stained glass, wood, steel, gourds and most any other material an artist can sculpt or manipulate. The part of the kaleidoscope which holds objects to be viewed is called an object chamber or cell. Object cells may contain almost any material. Sometimes the object cell is filled with liquid so the items float and move through the object cell with slight movement from the person viewing.

Etymology

First attested 1817 in English, the word "kaleidoscope" derives from the Greek καλός (kalos), "beautiful + είδος (eidos), "shape + σκοπέω (scopeο), "to look at, to examine.

History

Known to the ancient Greeks, it was reinvented by Sir David Brewster in 1816 while conducting experiments on light polarization; Brewster patented it in 1817. His initial design was a tube with pairs of mirrors at one end, and pairs of translucent disks at the other, and beads between the two. Initially intended as a science tool, the kaleidoscope was quickly copied as a toy. Brewster believed he would make money from his popular invention; however, a fault in the wording of his patent allowed others to copy his invention.

In America, Charles Bush popularized the kaleidoscope. Today, these early products often sell for over $1,000. Cozy Baker collected kaleidoscopes and wrote books about the artists who were making them in the 1970s through 2000. Baker is credited with energizing a renaissance in kaleidoscope-making in America. In 1997 a short lived magazine dedicated to kaleidoscopes called Kaleidoscope Review was published covering artists, collectors, dealers, events, and how-to articles.

Craft galleries often carry a few, while others specialize in them and carry dozens of different types from different artists and craftspeople.

Kaleidoscopes are related to hyperbolic geometry.

Background

For some background on the geometry of the kaleidoscope, see Reflection group.

See also

References

External links

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