Monday, December 14, 2009
A Mr. Arthur Fonzarelli from Milwaukee Wisconsin asks...
"Aaaaaaaaaaa...Mr. Knowital. How do mirrors work?"
Dear Fonz er Arthur...Generally speaking, by reflecting light!
Most objects don't give off any light of their own. They can only be seen because light from other sources such as The Sun, a candle, a light bulb, hits them and bounces off. Not all of the light bounces though. Some bounces, some is absorbed, and some is transmitted through the object. The part that does not bounce back is the reflection.. Flat shiny surfaces like water, metal, and mirrors reflect light well because very little of the light is absorbed or transmitted, most is reflected!
For centuries, mankind's only mirrors were pools of water, or polished metal. The first mirrors were made by Venetian craftsmen in the 1300's. They covered the back of a piece of glass with an amalgam of tin and mercury, rubbed flat and smooth. A piece of wool cloth would then be laid on top of the mercury, and pressed flat with iron weights for more than a week. Then the excess mercury would be drained off. This method remained a carefully guarded secret, and for centuries Venice had a monopoly on mirrors !!
In 1665 the chief Minister to Louis IV of France went to Italy and bribed 18 Venetian mirrorsmiths to move to France. Soon after their defection, the French passed a law banning Venetian mirrors!!
Three years later a Frenchman named Louis Lucas beat the Venetians at their own game. He invented plate glass! Venetians knew only how to make blown glass, and the size of the mirror was quite limited. But Lucas discovered how to pour molten glass onto an iron table where it could be flattened out with an Iron roller. Now mirrors could be made much larger. Soon France became famous for its large mirrors. Louis IV soon purchased 700 mirrors to line the hallways of the Palace of Versailles!
In 1835 German chemist Justus von Liebig discovered a way to make mirrors better. He invented a process for using silver instead of tin and mercury. He flushed the glass with silver salts, then covered it in a solution of silver nitrate. A chemical reaction caused the metalic silver to adhere to the glass. It was then coated with shellac and painted black. Thats how mirrors were made for the next 150 years!
I believe all mirrors are made in China now......
Good Question, Thanks!
Crazy Mirror Facts....
*In the 1600's the Dutch used to cover their mirrors with curtains when not in use, lest the reflectiveness be all used up! ( Crazy Dutch Bastards )
*In ancient China, reflective pieces of polished metal were placed over door knobs so that the evil spirits would scare themselves away!
*The word Mirror comes from the Latin Mirari, meaning to 'Wonder At'.
It's also the root word for Miracle and Admire!
*Building Mgr's install mirrors in lobbies because people complain less about waiting for slow elevators when occupied by looking at themselves.
*Lastly...Take a large piece of paper, and with a sharpie and your VERY best penmanship write down..."3M TA3"...Now hold up to the mirror!