Neon signs

The nighttime skyline of every city in the world heis changed as electric neon signs came to dominate the main commercial streets. The city with the most neon-lights is, of course. Las Vegas, Nevada. 

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Gas lasers are not unlike fluorescent light bulbs and neon signs. Gas is confined to a hollow tube, and electricity passing through it excites the atoms. The most common gas lasers use carbon dioxide, argon, and helium-neon. Gas lasers are relatively inexpensive and can produce very high-powered beams. 

Consider the apparatus shown in Figure 14-3. A glass tube is fitted with electrodes so that a potential difference of 10,000 volts can be applied across a space filled with a desired gas at various pressures. Suppose neon, for example, is placed in the tube. With the voltage applied, the gas will begin to conduct electricity when its pressure is reduced to about 0.01 atmosphere. The tube then glows with the familiar color of a neon sign. If a different gas is used, the color is different, but otherwise, the behavior is about the same. If the pressure is reduced still further to about 10 atmosphere, the glow from the gas... 

One of Cocktail Conceptions latest assignments was the cocktail menu at Schiller s Liquor Bar. It is Keith McNally s newest venture, at the corner of Rivington and Norfolk Streets. The white neon sign makes it look, cleverly, like an all-night pharmacy in a bad neighborhood. 

Figure 9.25 shows a typical neon lamp. It consists of a thin glass tube with an electrode at either end. A neon light requires an extreme voltage, which is provided by a so-called neon-sign transformer. Neon atoms are neutral, and cannot conduct electricity, but ionization of the gas-phase neon forms Ne+ ions (Equation (9.24)), so the tube contains a mixture of electrons and ions ... 

First I connected the 110V AC output of my mains transformer across the spark plug. It wouldn t strike a spark. If I connected the spark plug across the 4kV neon sign transformer I got a nice blue plasma. 

But if I connected the 110V AC output to the spark plug and tried to connect the neon sign transformer output also across the spark plug, I wouldn t have a spark because the secondary coil of the mains transformer "shorted" the spark plug out. 

Uses. Inert gas shield in arc welding air ships in mixtures with neon and argon for electronic tubes and neon signs... 

Tantalum is now made into spinnerets for the manufacture of rayon, into electrodes for the neon signs that give our Great White Ways a... 

Willie Ramsay, Sir William s thirteen-year-old son, inquired, What are you going to call the new gas I should like to call it novum. His father liked the suggestion, but thought that the synonymous term, neon, would sound better, and it is by this name that the gas discovered in June, 1898, is now known (16). In the brilliant neon signs on every business street one may now see at night the blaze of crimson light that brought such deep satisfaction and contentment to Professor Ramsay and Dr. Travers. 

A plasma is an appreciably ionized gas(about 1% or more) having no net charge, and may have a wide range of densities. Plasmas are of particular interest because of the possibility of initiating nuclear fusion in them, but they also appear in such phenomena as a neon sign, a lightning stroke, the ionosphere about the earth, shock waves, and the compressed layer of hot gas about an object entering the earth s atmosphere They appear in flames and detonation waves. It seems well established that free radicals and ions are present at well over equilibrium concentrations in flames (Ref 1). The ions appear to be produced not by thermal processes but by chemical factors which cause abnormal electronic excitation... 

Plasmas are of particular interest now because of the possibility of initiating nuclear fusion in them but they also appear in phenomena ranging from those found in a neon sign, a lightning stroke, the ionosphere about the earth, shock waves, and the compressed layer of hot gas around an astronaut s capsule as he comes back thru the earth s atmosphere ... 

Why does the ray of light in a neon sign bend when a magnet is held up to it ... 

Other light sources, however, emit a distinct number of discontinuous colors. Examples include streetlights, neon signs, sparklers, and fireworks. The spectral patterns... 

The neon sign is a fancy cathode ray tube, which means that the ray of light is the result of the flow of electrons through the tube. A magnet held up to these flowing electrons alters their path, which shows up as a distortion of the light ray. 

Atoms and Neon Signs An Array of Colored Light... 

Use arrows not highlighters. At best, it s difficult to read a page full of yellow, pink, blue, and green streaks. Try staring at a neon sign for a while and you ll soon see that the horde of colors obscure the message. 

If neon gas has a pressure of 200 mm when in a 12-liter tank, what is its pressure when put in a neon sign whose volume is 2 liters ... 

Ion Pump. A pump now much used in ultrahigh vacuum systems is the ion pump, of which the Varian Vac-Ion pump is an example. In this pump a gas discharge such as is commonly observed in air and other gases at about 10 Torr (e.g., neon signs, mercury and sodium lamps) is generated by a strong electric field and maintained all the way down... 

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