The Unsorted BBS Collection/thegreatunsorted.tar/thegreatunsorted/texts/term_papers/light.txt

Text File | 1993-06-20 | 6KB | 125 lines

                          LIGHT: A FUNDAMENTAL FORCE
                                IN OUR WORLD

































              LIGHT: A FUNDAMENTAL FORCE IN OUR WORLD

   If asked what light is, one could say that it's one of the most
basic elements of our world and our universe as we perceive it. It
is through sight that we receive 90% of our information. It is
through the use of telescopes aiding the naked eye that we are
aware of the heavenly bodies around us. It is through light that
the energy from the sun is transferred to us. The sun's energy
supports the food chain; plants use it to turn water and CO2 into
energy usable by other organisms. Solar energy was also used,
indirectly, to produce all of the fossil fuels that we consume
daily. Since light is such a basic part of our existence, we should
have a basic understanding of what it is.
  What we call light, the intangible, powerful force that powers
our world, is somewhat hard to define in real terms. It shares
properties with both particles and waves. It follows the same rules
as a wave does--it moves in a regular fashion, in a perfect sine
wave at a certain frequency. It travels in a straight line, and is
subject to refraction. All of these characteristics are found in
waves of any type, from radio frequency waves, up to Gamma and X-
rays. Light, however, also exhibits qualities characteristic of
particles such as neutrons and protons. A photon, or quanta, is the
"packet" of energy that is sent in a light wave. Like a particle,
the photon is believed to have a finite mass, and has the ability
to affect other matter. As light strikes a photovoltaic solar cell,
it knocks electrons in the silicon atoms on the surface into a
higher state of energy. When these return to their normal, or
"ground" state, energy is produced in the form of electricity.
Thus, light is termed a "wave-particle," and this property is
called the "wave-particle duality of nature." Many questions
concerning what makes up light still lie unanswered, but this much
is thought to be true.
  Light can be produced in a variety of ways. Our sun, like other
stars, uses nuclear fusion to produce energy in the form of light
and radiation. We can produce light artificially using several
methods. If one starts a fire, it produces light and heat. (Heat,
which is infrared radiation, is another type of light energy.) The
light and heat are a result of a chemical reaction, the combining
of oxygen with the carbon in the wood. This reaction leaves behind
products which have less potential energy than they started with.
The energy, which left as light and heat, was produced when
electrons dropped in energy levels during the reaction. The excess
energy from one atom was given off as a photon, producing light. If
one examines a fluorescent or incandescent light bulb, one can see
that all it is doing is having electricity stimulate a metallic or
gaseous substrate, causing it to give off photons. The principle is
the same as it was with the fire, only it is more controlled. Still
more controlled is the laser, which puts out its photons in a
single frequency. This is achieved through a carefully designed
apparatus which stimulates materials in a way that allows them to
only put out light at a certain wavelength. Laser light is,
therefore, of all one color. White light, or sunlight, is a broad
mixture of wavelengths. All methods of producing light, natural and
artificial, share one common feature: they rely on electrons
changing energy levels to produce the photons.
  As there are a variety of methods of producing light, so are
there a multitude of ways it can be applied. The most obvious use
of light is in supporting our food chain. Without light energy,
nothing could live on our planet. The plants, which are at the
bottom of the food chain, supply energy to all other organisms. We
as humans are adapted to having sunlight around us, and taking in
information with our eyes. Aside from keeping us alive, light is
also employed in highly specialized applications. Laser light is
being used in surgery. The highly concentrated beam of light is far
more precise than any surgeon's hand, and much finer than the
sharpest blade. In the area of communications, light is used in
fiber optic networks for fast, crystal-clear connections. (Fiber
optics allow light to travel in a finely directed path with very
little distortion.) Optical components in computers are starting to
see use. Also, lasers are being used to produce holographic images,
both for industrial and commercial markets. Holographic pictures
can show an object three dimensionally, and in great detail.
Finally, new ways of utilizing the sun's energy are being developed
that will allow light to be more efficiently converted to
electricity. Thus, light indeed has a wealth of applications.
  It must be remembered that, like most other things around us,
light is something utilized on a daily basis, yet little
understood. With continued research, we may someday unravel the
mysteries surrounding this unique force which is constantly at work
in our universe. The applications of light in the present are
nothing compared with what could be gained if we could understand
this strange mechanism; it may someday be the key to solving our
energy problems, or unlocking the secret of the universe.