“Let
there be Light”! Of course, this well-known Biblical quotation
pertains to the creating of the sun and moon or the “Greater
Luminary" and the “Lesser Luminary", so to speak. And,
there was and is light! During the daytime there is
plenty of light. In mankind's estimation, it is said that the sun as
a light source is equal to 2.5 billion
billion billion foot-candles! That should be enough for daylight,
when it isn’t an “overcast” day. But, evidently, as beautiful
and romantic as the moonlight may be, it appears that the record
shows man was not satisfied with it. Otherwise, when dusk comes and
then the darkness
,
we would all give up and retire! And perhaps that would not be a bad
idea, for then most of us would get at least twelve or more hours of
sleep a night.
However,
man is a curious fellow and he has an insatiable desire to “take
in” all that he can in a day’s time, stretching it to the limit.
So, man’s world, for the most part, revolves around proper
lighting and the ability to see. He sees and is able to have
pleasure and he sees and he is able to work...and he wants to be
able to do his work or play at his convenience. Thus, man found the
need to invent additional sources of light.
No
doubt man’s earliest sources of light were flaming torches and
campfires. These were inefficient and gave off much smoke and
pollution. Then he invented lamps which were simply wicks dipped in
oil. The oil burned and gave off a somewhat better light. Candles
were widely used during the Middle Ages. And, next in line were the
gaslights. When they were first introduced, the flame alone provided
the light. Then gas mantles were invented which provided materials
that glowed brilliantly when heated by the gas flame. At the same
time, lamps were developed that burned kerosene or whale oil. All of
these sources worked, but added pollution to our air and could start
fires. So, the inventing continued.
William
Gilbert (1540-1603) an English physician, made one of the first
important discoveries about static electricity. Gilbert told of the
attraction of amber differs from that of magnetic loadstones. Amber,
when rubbed with a cloth, attracts only light objects. He also found
that other substances such as sulfur, glass, and resin, behave like
amber. Our word for electricity comes from elektron, the
Greek word for amber.
In
1646, Sir Thomas Browne, also and English physician, used the word
electricity for the first time.
In
1733, Charles Du Fay of France thought there were two kinds of
electricity. One he named vitreous, meaning (as on glass) and
the other resinous meaning (as on amber). He learned that all
objects charged with vitreous electricity repel each other but
attract all objects charged with resinous electricity.
A
man named Benjamin Franklin was given credit for showing the
connection between lightning and natural electricity. He made a silk
kite and fastened a piece of wire near its top. Then he attached a
long string to the kite and tied an iron key to the free end of the
string. In 1752, Franklin sent the kite up in a heavy thunderstorm,
and as a thundercloud came near the kite, Franklin saw the loose
ends of the string stiffen. He put his hand near the key and
instantly he felt a shock as a spark traveled from the key to his
finger. Rain was falling heavily and the wet kite carried such a
large charge of electricity that some of it charged a battery in a
container called a Leyden jar. So, batteries change chemical energy
to electricity. It sounds simple enough, but it was a very dangerous
experiment yet it led to another invention of his.
Also
in l752, Franklin built the first lightning rod. It is the principal
behind the device that protects homes and other buildings from
damage by lightning. The discovery of electricity is what lead to
the artificial lighting or electric light that we depend on so much
today.
Charles
Augustin de Coulomb in l785 worked out the laws of attraction and
repulsion between electrically charged bodies.
In
l786, Luigi Galvani, and anatomy professor in Italy experimented
with current electricity, but did not quite get it right. He
fastened the legs of a freshly killed frog to a copper hook, and
hung the hook over an iron railing. The frog’s legs twitched
violently whenever they touched the iron. He concluded wrongly that
the frog’s legs contained electricity that was released when the
legs touched metal.
In
l800, Alesandro Volta, and Italian physics professor, discovered
further that the chemical action of moisture and two different
metals, such as copper and iron in Galvani’s experiments produced
the electricity. Volta built the first battery.
Hans
Christian Oersted, a Danish scientist, discovered electromagnetism
in l820. He learned that a current flowing through a wire would move
a compass needle. (This showed that an electric current has a
magnetic effect).
Also
in l820, the French physicist Andre Marie Ampere measured the
magnetic effect of an electric current. He learned that two wires
that are carrying current attract and repel each other just as
magnets do. By l822, Ampere had worked out the laws that formed the
basis for the science of current electricity.
In
l826, Georg Simon Ohm, a German schoolteacher, formulated the law of
electrical resistance that bears his name. Can you see the origin of
our words Volts, Amps, and Ohms here?
A
German physicist, Thomas Johann Seebeck, in l826 too, discovered
thermo-electricity, the principle that heat can produce electricity.
Next,
in 1831, and English physicist , Michael Faraday found that a moving
magnet would induce an electrical current in a coil of wire. An
American, Joseph Henry, also discovered this principle---thus,
all-electric generators and transformers work by means of these
principles.
In
the l860’s, James Clerk Maxwell, a Scottish physicist, worked out
the exact mathematical equations for the laws of electricity and
magnetism. He also predicted that electromagnetic waves, or radio
waves, that move at the speed of light could be produced.
Heinrich
Rudolph Hertz, a German physicist, produced such waves in the late
l880’s and later showed that they move at the speed of light.
*
The English physicist Joseph John Thomson discovered in l897 that
all atoms contain particles of electricity. All these particles are
exactly alike, no matter what kind of atoms they come from. We know
these particles today as electrons. His discovery helped make
possible the electronic age in which we live.
*
In the l950’s, American and British scientists harnessed the power
of atomic energy to generate electricity.
We
bet you had not known all of those facts!
The
first electric lights were arc lights, and a flaming arc between two
carbon rods produced the light. The so-called incandescent lamp has
a filament of carbon, tantalum and tungsten have been used for these
filaments. Some modern lights depend upon the passage of electricity
through a gas. A mercury lamp gives off light when an electric
current is passed through a mercury vapor. A lamp like this also
gives off ultraviolet rays. Florescent lights too, depend on mercury
vapor. They give off light when the ultraviolet rays resulting from
the passage of electricity through a mercury vapor strike certain
materials called phosphors. These substances in turn, give off
visible light!
Thus,
we now know how electric lighting was invented, and that is through
much curiosity and perseverance of dedicated men. And the apparatus
used to house the electricity such as the lamp, of which there are
thousands of beautiful designs and more elegantly, the chandelier
has become of great interest in cultural decor.
When
we think about all that we can do with the help of good lighting and
all that we would not be able to do, we can be overwhelmingly
grateful we live in a world in which we can enjoy all of the other
inventions man has produced at any time of the day or night. So the
next time you flick that switch, you can smile and say
“LET THERE BE LIGHT!”
