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The History of

 Visible light is electromagnetic radiation within a certain portion of the electromagnetic spectrum. Timeline of

Before After Electricity   Gas Discharge -Vapor Lamp   Light Bulb   Flourescent Lamp  Gas Lamp   LED(Light Emitting Diode) Fire (B.C. 1.4 million years)

 Fire is the first artifical light and heat source used by humans for , making tools. Candle (3000 B.C. )

 The Egyptians were using wicked in 3,000 B.C. but the Ancient Romans generally credited with developing the wicked candle before that time by dipping rolled papyrus repeatedly in melted tallow or beeswax.  Most early Western cultures relied primarily on candles made from animal fat. A major improvement came in the Middle Ages, when beeswax candles which didn’t smell bad and didn’t produce were introduced in Europe.  Beeswax candles were widely used for church ceremonies, but because they were expensive, few individuals could afford to use them as a main lighting source. Torch (B.C.1300)

 When early humans first started using fire, they were trying to find many uses for it. One of those uses is the torch which is a simple carrier of light and fire. Oil Lamp (10,300 - 8000 BC)

The use of oil began thousands of years ago and continues to this day, although not commonly anymore. Gas Lamp

 William Murdoch was the first man who used flammable gas as lighting. In the early 1790s Murdoch began experimenting with various types of gas, finally settling on coal-gas as the most effective. After Electricity

The Discovery of Electricity

 Electricity is the flow of moving electrons.  In ancient Greek it was observed that when the rubbed with other objects, it produces energy and it was callled electricity, which was first used here.  But, in fact, electricity was consciously used by the Italian physicist Alessandro Volta in 1800. GAS DISCHARGE LAMP How was it invented?

 The history of gas-discharge lamps began in 1675 when French astronomer Jean-Felix Picard observed that the empty space in his mercury barometer glowed as the mercury jiggled while he was carrying the barometer.  Investigators, including Francis Hauksbee, tried to determine the cause of the phenomenon. Hauksbee first demonstrated a gas-discharge lamp in 1705. How does it work?

 Gas-discharge lamps are a family of artificial light sources that generate light by sending an electrical discharge through an ionized gas, a .  Most of the discharge lamps require high voltage to operate. Since the normal mains voltage does not provide this, the voltage is increased either with the transformers or with the . Discharge tubes from discharge lamps are thermoionic valves. ARC LAMP How does it works?

 An arc lamp is a specialized type of gas discharge lamp, an that produces light by passing electricity through ionized gas at high pressure.  It produces a bright white light that closely mimics natural sunlight.  In 1801, at the age of 22,  He was laid in 1809. Two Davy was appointed director charcoals in the form of of the Royal Institute's charcoal attached to the laboratory in London, where opposite terminals of a he began working on battery. When the two electrochemistry. Davy, the carbon electrodes held a first step in the product that few centimeters away will be known later as an arc from each other, the lamp. electric spring passed through the two charcoals to complete the circuit. LIGHT BULB How was it invented ?

 The first person to make a working light bulb was Humpry Davy but It was not bright enough nor did it last long enough to be practical but it laid to foundation for modern light bulbs.  English Joseph Wilson and American Thomas Alva Edison invented light bulbs with a longer lifespan in the same year.  In 1880 made a lightbulb with an even longer lifespan. How does it work?

 In fact, bulbs have a very simple structure. We all know that a metal passing through the electrical current shows resistance. It gets hot in the face of resistance.  You can see this in the nearest electric stoves and electric heaters. Here is the light bulb works according to this principle.  There is a wire we call very thin filament in the bulb. As a result of the passing through this wire, the wire starts to radiate light (about 3000 C) by overheating. FLORUESCENT How was it invented?

 In Nela Park, USA, Co. And was introduced at the annual meeting of the Association of Lighting in Cincinnati in September 1935. At 60 cm length, the green was introduced to the public as a "great promising experiment". How dose it work?

 A is a low pressure mercury- vapor gas-discharge lamp that uses to produce visible light.  Fluorescent lamp fixtures are more costly than incandescent lamps but the lower energy cost typically offsets the higher initial cost. HALOGEN LAMP How was it invented ?

 Elmer Fridrich and Emmett Wiley invented the halogen lamp in 1959. In 1960 an engineer named General Electric Fredrick Moby invented a version of the halogen lamp developed.  A halogen lamp is an incandescent lamp that has a small amount of a halogen such as iodine or bromine added. LED (Light-Emitting Diode)  LED is a , diode based, light emitting electronic circuit element. It was invented in Russia in the 1920s.  In 1962 it was made into an electronic material that is practically applicable to America. Nobel Winning Blue LEDs

 Home-office lighting and the discovery of energy- efficient blue light-emitting diodes that are essential for the operation of electronic goods have earned the 2014 Nobel Prize for three scientists in physics. LED’s Effects on Human Health  Exposure to LED’s when sleeping can effect the emission of melatonin resulting in faster aging, slower healing of wounds and a %30 increased chance of getting cancer.  They can also cause obesity.  The Ohio State University experiment on rats proved that even a small light during sleep caused depression. (Light Amplification by Stimulated Emission of Radiation)

 A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The term "laser" originated as an acronym for "light amplification by stimulated emission of radiation".