They Do It With Mirrors Trivia Quiz

Answer: Kaleidoscope

The word kaleidoscope comes from Greek words which translate literally as 'observer of beautiful shapes'. Sir David Brewster invented the device in 1816, during research into polarized light, and expected it to be a serious scientific tool, but it was quickly turned into a children's toy.

The long main tube contains several mirrors along its length, set at angles to produce multiple reflections of the objects; the pattern depends on the number of mirrors used and the angle between them. As the tube is rotated, the loose colored objects fall into different positions, producing an ever-changing pattern.

Some kaleidoscopes simply have mirrors, producing a pattern based on reflections of the external environment.

Answer: Heliograph

A heliograph is a mirror that reflects sunlight (or, at night, an artificial light source) to a fixed destination point. The beam of reflected light is interrupted by tilting the mirror or by mechanical occlusion, depending on the exact type of heliograph.

The pattern of flashing light can be interpreted by the receiver if it uses a known code, such as Morse code. This means of communication became an important military resource during the 19th century, and was still supplied to many armies through the middle of the 20th century. By setting up a series of appropriately-placed relay stations, messages could quickly be sent over hundreds of miles, even through country which would have been impassable for a messenger on the ground.

The longest single transmission using a heliograph was made on September 17, 1894 when members of the U. S. Signal Corps at Mount Ellen, Utah communicated directly with members at Mount Uncompahgre, Colorado, 183 miles (295 km) away.

Answer: Dielectric

A dielectric mirror has one or more layers of dielectric material formed on it. Dielectric materials are readily polarized by electric fields; the constantly changing electric field of a light wave interacts with the material to an extent that is determined by the frequency of the light and the nature of the material. The combination of materials and their thickness in each layer can be designed to create a film that absorbs all light outside the specific desired range. These selectively-reflecting mirrors are useful in optical experimentation, and for applications involving lasers, which produce light of a very small frequency range.

An opaque coating would block all light; a translucent coating would distort the light to produce a blurred effect; a transparent coating would allow all light to pass through - the glass on the back of which a reflective metal film is mounted in most standard mirrors is such a substance.

Answer: Window

The other three terms are all used to describe a partially-reflective mirror, which reflects some of the light back into the original room, but allows some to pass through. Those in the original room see it as a mirror, as they are only aware of the light that is reflecting back into their room. This effect is maximized by keeping the room on the other side of the glass darker so that any light coming in from it is at a reduced intensity. People in the darker room can see clearly what is happening in the more brightly-lit room. These mirrors are used in police interrogation rooms, in market research investigations, by security observers in public places, and on television shows such as Big Brother in order to allow surveillance with minimal intrusion. They also have serious scientific uses (check out the Michelson-Morley experiment that proved the non-existence of the ether) as well as being useful in producing 'magic' illusions such as Pepper's ghost.

An ordinary glass window can act as a one-way mirror, as you may have noticed at night, when the room you are in is much more brightly lit than is the area outside the window. Glass does reflect some of the light that hits it, but under normal circumstances the reflected amount is so little that it is not noticed. If there is virtually no light coming in through the window, then the small amount of reflection can be seen.

Answer: Catoptric chest

Catoptrics refers to phenomena associated with reflected light and mirrors, especially those that form images. The word is of Greek origin, and was the name of the book by Euclid that developed the mathematical theory of mirrors and image formation by plane and concave mirrors.

The Roman catoptric chests, also called catoptric cistulae or catoptric theatres, were polygonal (often hexagonal) boxes lined with mirrors so that objects placed inside it were reflected multiple times as the reflection from one side crossed the box and was reflected again from the opposite side. A viewer would see many images, appearing to go off into a far distance in a space much larger than the chest itself.

Answer: Concave parabolic

When light is emitted from a globe placed at the focal point of a concave parabolic mirror, the reflected light is directed parallel to the parabola's axis of symmetry. Concave parabolic mirrors are also used to reflect parallel light rays from a distant source so that they all meet at the focal point, producing an increased intensity. The familiar shape of a satellite dish is a concave parabola.

Concave surfaces, curved so that the light approaches a surface whose sides are curving towards it, cause the light from a distant source to focus. Spherical mirrors do not produce a single focal point, a fact which is described as spherical aberration. Parabolas produce a far superior focal point. Convex surfaces, curved so that the light approaches a surface whose sides are curving away from it, cause the light to be spread out. Plane, or flat, surfaces change the direction of the reflected light uniformly.

Answer: Heliostat

Because a mirror reflects incident light so that the angle of incidence equals the angle of reflection, the position of the light reflected from a stationary plane mirror will change as the incident light from the sun changes its position. To keep the reflected light reaching the same point, a heliostat is a mirror (usually computer-controlled) which changes its position so that its reflective surface is perpendicular to the bisector of the angle between the sun and the target as seen from the mirror.

Heliostats are used to provide a steady light source in solar power stations.

Answer: Constructing carbon nanotubes

The temperature of a solar furnace is controlled by adjusting the mirrors. Solar furnaces can be used to accomplish tasks ranging from cooking, through generating electricity, melting metals, breaking methane down to produce hydrogen, and (at the highest temperature of any of these applications) constructing carbon nanotubes, also known as buckytubes.

These carbon allotropes, with properties that make them useful in electronics and other fields, belong to the fullerene structural family, named after Richard Buckminster Fuller whose geodesic domes had a shape similar to that of buckminsterfullerene, the first fullerene to be discovered.

Answer: To provide sunlight in the town square all year round

Viganella is located in the mountains in northern Italy. Because it is in a steep-sided valley, direct sunlight does not naturally reach the town for a period of about 10 weeks a year. The town decided to install a giant mirror that would reflect light into the center of town, and set up a heliostat for that purpose in November of 2006, providing year-round sunlight for the town.

This is the subject of the 2009 Canadian/Italian film "The Mirror".

Answer: Spark ball

Variously called a disco ball, mirror ball, glitter ball, ball mirror, or specular sphere, this is a large sphere (roughly) whose surface consists of hundreds or thousands of small plane mirrors. Hung from the ceiling and illuminated by spotlights, it reflects light in many directions, because the mirrors are all at slightly different angles. As it rotates, the spots of light seem to dance around the room.

These balls have been used since at least 1897, when one was used for a ballroom dance in Boston, Massachusetts. They were widely used in nightclubs during the 1920s, and became all the rage in discotheques during the 1960s, 1970s and 1980s, from which era they received the name 'disco ball'.