MIRRORSMIRRORSWhat do you see when you look into the mirror?

A History of Mirrors

A history of the mirror is really the history of looking, and what we perceive in these magical surfaces can tell us a great deal about ourselves – whence we have come, what we imagine, how we think, and what we yearn for.

Mirrors have been featured in folklore, religion, magic, science, art, and literature. They have appeared in a myriad of forms and usage that have included revealing, hiding or distorting reality, as a communication device, weapons of war, to search the stars, to ward off evil spirits, for divination,etc.

A mirror is an object with at least one reflective surface. The most familiar type of mirror is the plane mirror,

which has a flat surface.

Curved mirrors are also used, to produce magnified or diminished images or focus light or simply distort the reflected

image.Mirrors are commonly used for personal grooming or

admiring oneself (in which case the old-fashioned term "looking-glass" can be used), decoration, and architecture.

Mirrors are also used in scientific apparatus such as

telescopes and lasers, cameras, and industrial machinery.

Most mirrors are designed for visible light; however, mirrors designed for other types of waves or other wavelengths

of electromagnetic radiation are also used, especially in non-optical instruments.

MIRRORSMIRRORS

InstrumentsTelescopes and other precision instruments use front silvered or

first surface mirrors, where the reflecting surface is placed on the front (or first) surface of the glass (this eliminates reflection from glass surface ordinary back mirrors have).

For scientific optical work, For scientific optical work, dielectric mirrorsdielectric mirrors are often used. These are often used. These

are glass (or sometimes other material) substrates on which one or more are glass (or sometimes other material) substrates on which one or more layers of dielectric material are deposited, to form an optical coating.layers of dielectric material are deposited, to form an optical coating.

A dielectric coated mirror used in a dye laser

Mirrors and superstitionMirrors and superstitionIt is a common superstition that someone who breaks a mirror

will receive seven years of bad luck.

According to legend, a vampire has no reflection in mirrors because it is an undead creature and has already lost its soul.

Another superstition claims it is bad luck to have two mirrors facing each other.

In days past, it was customary in the southern United States to cover the mirrors in a house where the wake of a deceased person

was being held.

It was believed that the person's soul would become trapped in a mirror left uncovered. This practice is still followed in other

countries (e.g., Romania), extending to everything that could reflect the deceased person's face (such as TVs and appliances ).

Mirror in literature - NarcissusMirror in literature - Narcissus

In literature, Ovid In literature, Ovid (trans. 1986) warned of (trans. 1986) warned of the danger of exclusive the danger of exclusive preoccupation of oneself preoccupation of oneself at the expense of others in at the expense of others in the Greek myth of the Greek myth of Narcissus, who fell in love Narcissus, who fell in love with his own reflection.with his own reflection.

The mirror’s metaphysical qualities was explored in Lewis Carroll’s (1982/2008) alternate reality in Through the Looking-Glass, and What Alice Found .

Through the Looking-Glass, and What Alice Found .

Alice entering the Looking Glass. Illustration by Sir John Tenniel

There, in the story of Snow White (Grimm & Grimm, 1987/2003) the magic talking mirror saw all that was happening in the kingdom, and the Mirror of Erised (Rowling, 2008), reflected the image of what the heart desired most.

For For Harry Harry Potter,Potter, it was the it was the

sight of his sight of his deceased family.deceased family.

Image with mirrorsImage with mirrors

Image with and in mirrorsImage with and in mirrors

Shape of a mirror's surface Shape of a mirror's surface In a plane mirror, a parallel beam of light changes its direction as a

whole, while still remaining parallel; the images formed by a plane mirror are virtual images, of the same size as the original object (see mirror image).

In a concave mirror, parallel beams of light becomes a convergent beam, whose rays intersect in the focus of the mirror.

In a convex mirror, parallel beams become divergent, with the rays appearing to diverge from a common point of intersection "behind" the mirror.

Spherical concave and convex mirrors do not focus parallel rays to a single point due to spherical aberration. However, the ideal of focusing to a point is a commonly-used approximation. Parabolic reflectors resolve this, allowing incoming parallel rays (for example, light from a distant star) to be focused to a small spot; almost an ideal point. Parabolic reflectors are not suitable for imaging nearby objects because the light rays are not parallel.

Plane mirrorsPlane mirrors

A mirror, reflecting a vaseA mirror, reflecting a vase

Concave MirrorsConcave Mirrors

Convex MirrorsConvex Mirrors

Spherical MirrorsSpherical Mirrors

Reflection from Mirrors Reflection from Mirrors

Reflection from a Plane MirrorReflection from a Plane Mirror

The image distance always equals The image distance always equals the object distance. The size of the the object distance. The size of the image is the same as the object (the image is the same as the object (the mirror does not magnify the image). mirror does not magnify the image).

Reflection from a Concave MirrorReflection from a Concave Mirror

When the object is far from the mirror, the image is When the object is far from the mirror, the image is inverted and at the focal point. The image is real light rays inverted and at the focal point. The image is real light rays actually focus at the image location). As the object moves actually focus at the image location). As the object moves towards the mirror the image location moves further away towards the mirror the image location moves further away from the mirror and the image size grows (but the image is from the mirror and the image size grows (but the image is still inverted). still inverted).

When the object is that the focal point, the image is at When the object is that the focal point, the image is at infinity. As the object moves towards the mirror inside the infinity. As the object moves towards the mirror inside the focal point the image becomes virtual and upright behind focal point the image becomes virtual and upright behind the mirror. Initially the virtual image is much larger than the mirror. Initially the virtual image is much larger than the object and really far away, but as the object approaches the object and really far away, but as the object approaches the mirror the virtual image also approaches the mirror and the mirror the virtual image also approaches the mirror and decreases in size. decreases in size.

Reflection from Convex MirrorReflection from Convex Mirror

The image produced by a convex The image produced by a convex mirror is always virtual, and located behind mirror is always virtual, and located behind the mirror. When the object is far away the mirror. When the object is far away from the mirror the image is upright and from the mirror the image is upright and located at the focal point. As the object located at the focal point. As the object approaches the mirror the image also approaches the mirror the image also approaches the mirror and grows until its approaches the mirror and grows until its height equals that of the object. height equals that of the object.

The Archimedes Heat RayThe Archimedes Heat Ray

Archimedes may have used mirrors acting Archimedes may have used mirrors acting collectively as a parabolic reflector to burn ships attacking collectively as a parabolic reflector to burn ships attacking Syracuse.Syracuse.

The 2nd century AD author Lucian wrote that The 2nd century AD author Lucian wrote that during the Siege of Syracuse (c. 214–212 BC), Archimedes during the Siege of Syracuse (c. 214–212 BC), Archimedes destroyed enemy ships with fire. Centuries later, destroyed enemy ships with fire. Centuries later, Anthemius of Tralles mentions burning-glasses as Anthemius of Tralles mentions burning-glasses as Archimedes' weapon.Archimedes' weapon.

The device, sometimes called the "Archimedes heat The device, sometimes called the "Archimedes heat ray", was used to focus sunlight onto approaching ships, ray", was used to focus sunlight onto approaching ships, causing them to catch fire.causing them to catch fire.

Archimedes may have used mirrors acting collectively as a Archimedes may have used mirrors acting collectively as a parabolic reflector to burn ships attacking Syracuse.parabolic reflector to burn ships attacking Syracuse.

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  About the Design of KaleidoscopeAbout the Design of Kaleidoscope

                    A kaleidoscope, or a caleidoscope, is a tube of A kaleidoscope, or a caleidoscope, is a tube of

mirrors containing loose, colored objects such as beads mirrors containing loose, colored objects such as beads and pebbles. The viewer looks in one end and light and pebbles. The viewer looks in one end and light enters the other end, reflecting off the mirrors. enters the other end, reflecting off the mirrors.

Kaleidoscopes operate on the multiple reflections Kaleidoscopes operate on the multiple reflections principle that several mirrors are attached together. principle that several mirrors are attached together. Generally there are two rectangular lengthwise mirrors. Generally there are two rectangular lengthwise mirrors.

Setting of the mirrors at 45°creates eight duplicate Setting of the mirrors at 45°creates eight duplicate images, six at 60°, and four at 90°. As the images, six at 60°, and four at 90°. As the kaleidoscope kaleidoscope tubetube is rotated, the tumbling of the colored objects is rotated, the tumbling of the colored objects presents the viewer with varying patterns. presents the viewer with varying patterns.

Make a KaleidoscopMake a Kaleidoscop

- (Physics / General Physics) an optical toy - (Physics / General Physics) an optical toy for producing symmetrical patterns by multiple for producing symmetrical patterns by multiple reflections in inclined mirrors enclosed in a tube. reflections in inclined mirrors enclosed in a tube.

Loose pieces of coloured glass, paper, Loose pieces of coloured glass, paper, etc., are placed between transparent plates at etc., are placed between transparent plates at the far end of the tube, which is rotated to the far end of the tube, which is rotated to change the pattern.change the pattern.

- is any complex pattern of frequently - is any complex pattern of frequently changing shapes and colours.changing shapes and colours.

KaleidoscopKaleidoscop

BibliographyBibliography

11. . www.thefreedictionary.com/kaleidoscope.www.thefreedictionary.com/kaleidoscope.22.. en.wikipedia.org/wiki/Mirror.en.wikipedia.org/wiki/Mirror.3. 3. www.kettering.edu/~drussell/Demos/Ray...www.kettering.edu/~drussell/Demos/Ray... 4. 4. www.experiencefestival.com/mirror_-_m...www.experiencefestival.com/mirror_-_m... 5. www.csicop.org/superstition/library/m...5. www.csicop.org/superstition/library/m... 6. en.wikipedia.org/wiki/Archimedes.6. en.wikipedia.org/wiki/Archimedes.77. . www.physicsforums.com/showthread.php%.www.physicsforums.com/showthread.php%.8. en.wikipedia.org/wiki/Mirror_image.8. en.wikipedia.org/wiki/Mirror_image.

PROJECT - MIRRORSPROJECT - MIRRORS

Prepared by:Prepared by:

MIREA DIANA MIREA DIANA