Ever Wondered How a Typical Mirror Works?
Mirror work tutorial,mechanical mirror works,mirror works detail
What is a mirror? It is something that reflects (throws back) your image.
Now, this reflection is possible only when there is light (sunlight or artificial
light). Try standing in front of a mirror in a totally dark room, and you
will realize what we mean!
If you take a close look at any mirror, you would notice that it basically
consists of a sheet of glass—large or small. What differentiates a mirror
from an ordinary piece of glass is the coating of aluminum or silver on
one side or on the back. And this coating is necessary; otherwise, how
would you be able to see yourself or any other object in your mirror?
For light falls on your face/body—then hits the mirror—the mirror throws
it back—the light enters your eyes—you are able to see an “image”.
Now, this idea of backing a glass sheet with something did not originate
till the 16th century. People belonging to the earlier Middle Ages, especially
the Greco-Romans, observed themselves in hand-held disks of highly polished
silver or bronze or tin! These disks were slightly convex in shape. The
Venetians decided to experiment, and came up with the idea of a combination
of mercury and tin (amalgam) to coat the surface of glass. This was replaced
by metallic silver in 1835 (Justus von Liebig). And so the techniques
of mirror-making kept advancing till modern times.
Take a look at the mirrors you have at home. You will notice that each
one is coated with silver or aluminum. Are you aware of the process? It
is not the result of painting with a hand-held brush. A thin layer of
molten aluminum or silver is sputtered onto the back surface of the glass
sheet or glass plate in a vacuum. If these mirrors are meant for use in
an optical instrument such as a microscope, a telescope and so on, the
aluminum is evaporated onto the front surface of the glass. This is to
prevent faint reflections from the glass itself.
For a mirror to function properly, it must be allowed to reflect as much
as possible the light falling on a body. The lesser the amount of light
absorbed or transmitted, the clearer the image. You will understand this
better with this example. Try looking at your face in the clear waters
of a pond. Is the visualization so clean that you feel like you are looking
into a mirror? Well then, the reflection of light is wonderful! Now, repeat
the action with the rather cloudy waters of a pond or lake. Are you able
to view a good image of yourself? If the answer is in the negative, then
the light falling onto your body is being absorbed and not reflected.
When a mirror is manufactured, care is taken to ensure that the surface
is perfectly smooth. If at all there are any irregularities, they are
too miniscule to affect the functioning. Of course, the surface can be
plane or curved (concave, convex). Again, the curved mirror can be of
varying types—spherical (used as rearview mirrors for automobiles, facial
makeup); cylindrical (to see upside-down images); paraboloidal (used in
telescopes and searchlights); and ellipsoidal and hyperboloidal (used
in other optical instruments).
