History of Mirrors

Since about 8,000 years ago humans have known and utilize mirror. At that time, people take advantage of that shiny piece of stone like obsidian to be used as a mirror. One evidence is the discovery of obsidian mirrors in Anatolia region, Turkey, which is expected to be made around the year 6000 BC. Discovery of mirror polished stones were also found in Central and South America are expected to be made around the year 2,000 BC.

Technology to create a mirror and then developed with the discovery of a mirror made of polished copper were made in Mesopotamia in 4000 BC and in Egypt in 3000 BC. In China, found a mirror made of bronze, which were made in 2000 BC. Metal-coated glass mirror invented in Sidon, Lebanon in the first century AD. The back of the mirror glass with gold leaf is also mentioned by the author of the Roman named Pliny in his Natural History book, which is composed around the year 77 AD The Romans also developed a technique that creates a rough mirror of glass blowing is coated with molten tin.

Like a parabolic mirror and a convex mirror concave mirror was first described by physicist named Ibn Sahl of Arabic in the 10th century AD Ibn al-Haytham discussed concave and convex mirrors in both cylindrical and spherical geometries, do some experiments with mirrors, and solved the problem to find the point on a convex mirror at which a ray coming from one point is reflected to another point. And in the 11th century, clear glass mirrors have been produced in Al-Andalus.

During the early Renaissance, European manufacturers perfected a superior method of coating glass that have been found previously using a mixture of tin and mercury. The exact date and location of the discovery is unknown, but is estimated in the 16th century, in Venice, a city known for its expertise making glass, a center of mirror production by using this technique. Glass mirrors from this period was once a luxury item that is very expensive and only used by the rich and the nobility.

Justus Liebig find a mirror reflective glass as used today in 1835. The process involves depositing a layer of metallic silver onto glass through the chemical reduction of silver nitrate. The process of coating glass with a reflective substance (silvering) is adapted to mass produce mirrors. Nowadays, mirrors are often produced by depositing the aluminum (or sometimes silver) directly onto the glass substrate.

How it Works Mirror

Most modern mirrors consist of a thin layer of aluminum is covered with shattered glass. This mirror is called "old rear" (back silvered), where surface bounces seen through shattered glass. Coating the mirror with a mirror-resistant glass making, but it reduces the quality of the mirror for additional biasan front surface glass. The mirror like reverse about 80% of the incoming light. The back of the mirror is often painted completely black to protect the metal from erosion.

While optical telescopes and other equipment, using mirror "the elder" (front silvered), where the reflecting surface is placed on the glass surface, which gives a better quality shadows. Sometimes also used silver, but mostly uses aluminum mirrors, which reflect short wave better than silver. The old mirror reflects 90% to 95% of the incident light. Because of rusted metal in the presence of oxygen and moisture, the old mirror surface needs to be replaced over and over to maintain quality. Another way is, of course, using the vacuum to put this mirror.