History of Fiber Optics Essay Example

History of Fiber Optics Essay HISTORY OF FIBER OPTICS * In 1840, Daniel Colladon and Jacques Babinet demonstrated the principle of guiding light by refraction. * It was followed by a public demonstration by John Tyndal in 1852. In 1870, Tyndal wrote about the property of total internal reflection in his book about the nature of light. * In 1880, Alexander Graham Bell and Sumner Tainter invented the Photophone, a device capable of transmitting sound waves over beam of light. This is considered as mankind’s first attempt to to use light for carrying information. * In 1930, Clarence Hansel and John Logie Baird demonstrated independently image transmission using fiber. * In 1940’s, Heinrich Lamm successfully transmitted images through a single glass fiber used for internal medical examinations. * In 1951, Harold Hopkins and Narinder Singh Kapany experimented with light transmission through bundles of fiber. Their study led to the development of the flexible fiberscope, which is used in the medical field. It was also Kapany who coined the term fiber optics in 1956. * In 1953, Charles Townes and two of his graduate students developed the MASER (Microwave Amplification by Stimulated Emission of Radiation), and in 1960, Theodore Maiman developed the first LASER ( Light Amplification by Stimulated Emission of Radiation). In 1967, Charles Kao and George Bockham of the Standard Telecommunications Laboratory proposed the cladded fiber cables. * In 1970, Robert Maurer, Donalk Keck and Kapron of Corning Glass developed the first fiber optics with losses less than 2dB/Km. * In 1980’s, losses in fiber optics were reduced to as low as 0. 16 dB/Km. This is due to the development of high-quality light sources and detectors. * In 1990’s, the photonic crystal fiber was developed that can carry high power than the conventional silica based fibers. We will write a custom essay sample on History of Fiber Optics specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on History of Fiber Optics specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on History of Fiber Optics specifically for you FOR ONLY $16.38 $13.9/page Hire Writer

How to Purify Sodium Chloride From Rock Salt

How to Purify Sodium Chloride From Rock Salt Rock salt or halite is a mineral the contains sodium chloride (table salt) as well as other minerals and impurities. You can remove most of these contaminants using two simple purification techniques: filtration and evaporation. Materials Rock saltWaterSpatulaFilter paperFunnelEvaporating dishBeaker  or graduated cylinderTripodBunsen burner Filtration If the rock salt is one large chunk, grind it into a powder using a mortar and pestle or a coffee grinder.Add 30-50 milliliters of water to 6 heaping spatula scoops of rock salt.Stir to dissolve the salt.Place the filter paper in the mouth of the funnel.Place the evaporating dish under the funnel to collect the liquid.Slowly pour the rock salt solution into the funnel. Make sure you dont over-fill the funnel. You dont want the liquid to flow around the top of the filter paper because then it isnt getting filtered.Save the liquid (filtrate) that comes through the filter. Many of the mineral contaminants did not dissolve in the water and were left behind on the filter paper. Evaporation Place the evaporating dish containing the filtrate on the tripod.Position the Bunsen burner under the tripod.Slowly and carefully heat the evaporating dish. If you apply too much heat, you could break the dish.Gently heat the filtrate until all the water is gone. Its okay if the salt crystals hiss and move a little.Turn off the burner and collect your salt. Although some impurities remain in the materials, many of them were removed simply by using the difference in solubility in water, mechanical filtration, and by applying heat to drive off volatile compounds. Crystallization If you want to further purify the salt, you can dissolve your product in hot water and crystallize the sodium chloride from it.