Science Notes by Ahmet Arduc - Mirrors and Reflection
by Ahmet Arduc – www.ahmath.com
And, unlike cars, computers, airplanes, or light bulbs, they use up none of the
earth’s limited resources. They simply take advantage of the natural properties of
We see objects in the world around us because light is reflected off those objects
and enters our eyes, which are specially adapted to send messages to the brain so it
can interpret it as information.
We see because our eyes are sensitive to light. Our eyes collect natural and artificial
light that is then interpreted by the brain and turned into visual pictures.
Since the beginning of history,
humankind has been interested in
studying both how light behaves
normally and how it can be
The easiest way to explain how light
behaves is to think of light as
travelling in imaginary straight lines
When you turn on an ordinary light bulb, you can imagine that the
light that floods the room is made up of rays that radiate out from
the bulb in every direction. We cannot count all the rays coming
from the light bulb, or from any other light source, but we can pick
just a few rays and use them to represent the overall direction and
movement of light.
The light that is reflected off objects is basically the same as the light
that comes from any other light source -such as an overhead light, or
even the sun- in that it travels in straight lines called rays.
One such case is when light
hits a smooth, shiny, or
metallic surface. When this
happens, very little light is
absorbed, and the light is
reflected in a very regular and
When light hits most
surfaces, those rays that are
not absorbed by the surface
are bounced off randomly in
all directions. But there are
special cases in which light
rays are reflected in ways that
can be predicted.
F117-Nighthawk. It has flat surfaces, called facets, and very sharp edges.
In general, it is
acceptable to imagine
that light rays travel in
straight lines until they
hit something. What
happens next depends
on what they hit. Most
often, light hits the
surfaces of common,
everyday objects like, for
example, a desk with a
book on it. When the light hits the desk and book, most of the light
is simply absorbed, but some is reflected. If someone in the room
were to look at the desk, some of the reflected light would enter his
or her eyes and enable the brain to form a picture.
The simplest way
to explain this is to
imagine that the
light rays bounce
off the surface at
the same angle at
which they strike
the surface, much
like a rubber ball
bouncing on the
Reflections in a mirror are
formed when light rays
bounce off an object and
strike the mirror. When light
rays strike the surface of a
mirror, they again bounce
off, or are reflected by, the
A periscope lets you see over the
top of things, such as fences or
walls that you aren't tall enough to
A simple periscope is just a long
tube with a mirror at each end.
The mirrors are fitted into each
end of the tube at an angle of
exactly 45 degrees (45°) so that
they face each other.
People have been using smooth, shiny, metallic surfaces for thousands
of years to reflect light for various purposes. A flat (plane) mirror is
any device designed to reflect light in a regular pattern so that
the reflected image remains true. Usually, a mirror is made from a
highly reflective silvery substance covered by glass or sturdy clear
plastic to protect the surface.
Because the surface of a flat mirror is smooth and shiny, light rays
are reflected off of the mirror at the same angle at which they strike
the mirror. Thus they form an exact replica ‘inside’ the mirror of the
object in front of the mirror. This principle is known as the law of
Lenses and mirrors are two of the most
significant inventions in our history.
From bathroom mirrors and reading
glasses to the most advanced optical
instruments used by scientists on earth
and in space, lenses and mirrors affect
our lives in very important ways.
For many people, light from an
image is not perfectly focused on
their retina. Depending on the
severity of the deviance, this can
lead to a person needing to wear
glasses. A short-sighted person
can see things close-up, but has
trouble seeing things further
away. A long-sighted person
struggles to see near objects, but
can see distant objects.
Most of the things we see every day are not sources of light, so it is
not inherently obvious that we only see light. We see things that are
not light sources - common, everyday objects - because light bounces
off them and into our eyes.
light emitted by a light source can reach
the eye either directly or indirectly.
When light bounces off the surface of
an object, the object is said to be visible.
The sun, the flame of a candle or the
incandescent filament of a light bulb
are visible to the eye because they emit
their own light. These objects are called
The different colors and shades of light and dark that we see are due
to the different ways in which light bounces off the objects in the
world around us.
Visible light is just a kind of
electromagnetic radiation that
our eyes can detect.