Reflection

2.9 The manufacture of mirrors

Explain the use of different substances to manufacture mirrors. **
 

Mirrors appeared several centuries before the time of Christ. At that time, they took the form of metallic plaques of silver, bronze, tin, or gold.

Mirrors made of glass appeared in the18th century. At first, the glass was coated with lead. Due to the complex process of heating the lead to temperatures sufficiently high to stick to the glass, mirrors were not manufactured on a large scale.

The process was improved by the introduction of a tin amalgamate. It adhered to the glass at ordinary temperatures. Thereafter, the use of mirrors became commonplace.

Today, almost all conventional mirrors are made according to the same principle. A plate of glass protects the chrome alloy reflecting surface. The back of the mirror is coated with an opaque paint. Its function is to protect the delicate reflective surface and to absorb any light that might pass through it.