1.
Oxidizing agent
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In chemistry, an oxidizing agent is a substance that has the ability to oxidize other substances. Common oxidizing agents are oxygen, hydrogen peroxide and halogens, in one sense, an oxidizing agent is a chemical species that undergoes a chemical reaction that removes one or more electrons from another atom. In that sense, it is one component in an oxidation–reduction reaction, in the second sense, an oxidizing agent is a chemical species that transfers electronegative atoms, usually oxygen, to a substrate. Combustion, many explosives, and organic redox reactions involve atom-transfer reactions, electron acceptors participate in electron-transfer reactions. In this context, the agent is called an electron acceptor. A classic oxidizing agent is the ferrocenium ion Fe+2, which accepts an electron to form Fe2, one of the strongest acceptors commercially available is Magic blue, the radical cation derived from N3. Extensive tabulations of ranking the electron accepting properties of various reagents are available, in more common usage, an oxidising agent transfers oxygen atoms to a substrate. In this context, the agent can be called an oxygenation reagent or oxygen-atom transfer agent. Examples include MnO−4, CrO2−4, OsO4, and especially ClO−4, notice that these species are all oxides. In some cases, these oxides can also serve as electron acceptors, as illustrated by the conversion of MnO−4 to MnO2−4, by this definition some materials that are classified as oxidising agents by analytical chemists are not classified as oxidising agents in a dangerous materials sense. An example is potassium dichromate, which does not pass the dangerous goods test of an oxidising agent, the U. S. Department of Transportation defines oxidizing agents specifically. There are two definitions for oxidizing agents governed under DOT regulations and these two are Class 5, Division 5.1 and Class 5, Division 5.2. Division 5.1 means a material that may, generally by yielding oxygen, combustion Dye Electrosynthesis Organic oxidation Organic redox reaction Reducing agent
2.
Fuel
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A fuel is any material that can be made to react with other substances so that it releases chemical or nuclear energy as heat or to be used for work. The concept was applied solely to those materials capable of releasing chemical energy but has since also been applied to other sources of heat energy such as nuclear energy. The heat energy released by reactions of fuels is converted into mechanical energy via a heat engine, other times the heat itself is valued for warmth, cooking, or industrial processes, as well as the illumination that comes with combustion. Fuels are also used in the cells of organisms in a known as cellular respiration. Hydrocarbons and related oxygen-containing molecules are by far the most common source of fuel used by humans, fuels are contrasted with other substances or devices storing potential energy, such as those that directly release electrical energy or mechanical energy. The first known use of fuel was the combustion of wood or sticks by Homo erectus near 2,000,000 years ago, throughout most of human history fuels derived from plants or animal fat were only used by humans. Charcoal, a derivative, has been used since at least 6,000 BCE for melting metals. It was only supplanted by coke, derived from coal, as European forests started to become depleted around the 18th century, charcoal briquettes are now commonly used as a fuel for barbecue cooking. Coal was first used as a fuel around 1000 BCE in China, coal was later used to drive ships and locomotives. By the 19th century, gas extracted from coal was being used for lighting in London. In the 20th and 21st centuries, the use of coal is to generate electricity. Fossil fuels were rapidly adopted during the revolution, because they were more concentrated and flexible than traditional energy sources. They have become a part of our contemporary society, with most countries in the world burning fossil fuels in order to produce power. Currently the trend has been towards renewable fuels, such as biofuels like alcohols, chemical fuels are substances that release energy by reacting with substances around them, most notably by the process of combustion. Most of the energy released in combustion was not stored in the chemical bonds of the fuel. Chemical fuels are divided in two ways, first, by their physical properties, as a solid, liquid or gas. Secondly, on the basis of their occurrence, primary and secondary, solid fuels include wood, charcoal, peat, coal, Hexamine fuel tablets, and pellets made from wood, corn, wheat, rye and other grains. Solid-fuel rocket technology also uses solid fuel, solid fuels have been used by humanity for many years to create fire
3.
Explosion
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An explosion is a rapid increase in volume and release of energy in an extreme manner, usually with the generation of high temperatures and the release of gases. Supersonic explosions created by high explosives are known as detonations and travel via supersonic shock waves, subsonic explosions are created by low explosives through a slower burning process known as deflagration. When caused by a device such as an exploding rocket or firework. Most natural explosions arise from volcanic processes of various sorts, explosions also occur as a result of impact events and in phenomena such as hydrothermal explosions. Explosions can also occur outside of Earth in the universe in events such as supernova, explosions frequently occur during bushfires in eucalyptus forests where the volatile oils in the tree tops suddenly combust. Solar flares are an example of common explosion on the Sun, the energy source for solar flare activity comes from the tangling of magnetic field lines resulting from the rotation of the Suns conductive plasma. Another type of large astronomical explosion occurs when a large meteoroid or an asteroid impacts the surface of another object. The most common artificial explosives are chemical explosives, usually involving a rapid, gunpowder was the first explosive to be discovered and put to use. Other notable early developments in chemical explosive technology were Frederick Augustus Abels development of nitrocellulose in 1865, chemical explosions are often initiated by an electric spark or flame. Accidental explosions may occur in fuel tanks, rocket engines, etc, a high current electrical fault can create an electrical explosion by forming a high energy electrical arc which rapidly vaporizes metal and insulation material. This arc flash hazard is a danger to persons working on energized switchgear, also, excessive magnetic pressure within an ultra-strong electromagnet can cause a magnetic explosion. Strictly a physical process, as opposed to chemical or nuclear, examples include an overheated boiler or a simple tin can of beans tossed into a fire. Note that the contents of the container may cause a subsequent chemical explosion, in such a case, to the effects of the mechanical explosion when the tank fails are added the effects from the explosion resulting from the released propane in the presence of an ignition source. For this reason, emergency workers often differentiate between the two events, in addition to stellar nuclear explosions, a man-made nuclear weapon is a type of explosive weapon that derives its destructive force from nuclear fission or from a combination of fission and fusion. Explosive force is released in a perpendicular to the surface of the explosive. If a grenade is in mid air during the explosion, the direction of the blast will be 360°, if the surface is cut or shaped, the explosive forces can be focused to produce a greater local effect, this is known as a shaped charge. The speed of the reaction is what distinguishes an explosive reaction from a combustion reaction. Unless the reaction occurs rapidly, the thermally expanding gases will be moderately dissipated in the medium
4.
Pyrotechnics
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Pyrotechnics is the science of using materials capable of undergoing self-contained and self-sustained exothermic chemical reactions for the production of heat, light, gas, smoke and/or sound. Its etymology stems from the Greek words pyro and tekhnikos, individuals responsible for the safe storage, handling, and functioning of pyrotechnic devices are referred to as pyrotechnicians. Proximate refers to the devices location relative to an audience. In the majority of jurisdictions, special training and licensing must be obtained from local authorities to legally prepare, many musical groups use pyrotechnics to enhance their live shows. Pink Floyd were without a doubt the innovators of pyrotechnic use in concerts, for instance, at the climax of their song Careful with That Axe, Eugene, a blast of smoke was set off at the back of the stage. Bands such as The Who, KISS and Queen, soon followed use of pyrotechnics in their shows, michael Jackson attempted using pyrotechnics in a 1984 Pepsi advertisement, where a stray spark caused a small fire in his hair. German industrial metal band Rammstein are renowned for their variety of pyrotechnics. Nightwish, Lordi and Green Day are also known for their vivid pyrotechnics in concert, many professional wrestlers have also used pyrotechnics as part of their entrances to the ring. Modern pyrotechnics are, in general, divided into categories based upon the type of effect produced or manufacturing method, the most common categories are, Airburst - Hanging charges designed to burst into spheres of sparks. Binary powders - Kits divided into separate oxidizer and fuel, intended to be mixed on site, comet - Brightly colored burning pellets resembling shooting stars. Mine - Tubes containing a lift charge intended to project stars, sparks, preloaded Smoke Pot - Cartridges designed to release a mushroom cloud of smoke. Concussion - Device designed to create a loud report, falls - Propellant with titanium burning in an open ended tube creating a falling spark effect. Fireballs / Mortar Hits - Short barreled device projecting smoky rolling ball of flame, flame Projector - Tube containing nitrocellulose granules that burn in pillars of colored flame. Flare - Short, high intensity flames or various colours, flash Cotton - Nitrated cotton string. Flashpaper - Sheets of nitrated paper resembling tissue paper, flash Pot - Short metal pot used with binary powders creating flash, smoke or sparks. Flash Tray - A long tube slit down one side to project a sheet of flash, gerb - A fountain of sparks. Lance - A Small colored flare tube used in making points of light lancework or pictures in fire, line Rockets - Whistling or colored rocket devices that travel along guide cables. Multi-Tube Article - Multiple effects chained together, pre-Mixed Powder - Powders intended to create various effects
5.
Fireworks
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Fireworks are a class of low explosive pyrotechnic devices used for aesthetic and entertainment purposes. The most common use of a firework is as part of a fireworks display, Fireworks competitions are also regularly held at a number of places. Fireworks take many forms to produce the four primary effects, noise, light, smoke and they may be designed to burn with colored flames and sparks including red, orange, yellow, green, blue, purple, and silver. Displays are common throughout the world and are the point of many cultural. Fireworks were invented in ancient China in the 7th century to scare evil spirits. Such important events and festivities as Chinese New Year and the Mid-Autumn Moon Festival were, China is the largest manufacturer and exporter of fireworks in the world. Fireworks are generally classified as to where they perform, either as a ground or aerial firework, in the latter case they may provide their own propulsion or be shot into the air by a mortar. The most common feature of fireworks is a paper or pasteboard tube or casing filled with the combustible material, a number of these tubes or cases are often combined so as to make, when kindled, a great variety of sparkling shapes, often variously colored. The skyrocket is a form of firework, although the first skyrockets were used in war. The aerial shell, however, is the backbone of todays commercial aerial display, such rocket technology has also been used for the delivery of mail by rocket and is used as propulsion for most model rockets. The earliest documentation of fireworks dates back to 7th century China, the fireworks were used to accompany many festivities. It is thus a part of the culture of China and had its origin there, the art and science of firework making has developed into an independent profession. In China, pyrotechnicians were respected for their knowledge of techniques in mounting firework displays. Chinese people originally believed that the fireworks could expel evil spirits and bring about luck, during the Song Dynasty, many of the common people could purchase various kinds of fireworks from market vendors, and grand displays of fireworks were also known to be held. In 1110, a fireworks display in a martial demonstration was held to entertain Emperor Huizong of Song. A record from 1264 states that a rocket-propelled firework went off near the Empress Dowager Gong Sheng, rocket propulsion was common in warfare, as evidenced by the Huolongjing compiled by Liu Bowen and Jiao Yu. In 1240 the Arabs acquired knowledge of gunpowder and its uses from China, with the development of chinoiserie in Europe, Chinese fireworks began to gain popularity around the mid-17th century. Lev Izmailov, ambassador of Peter the Great, once reported from China and his writings would be translated in 1765, resulting in the popularization of fireworks and further attempts to uncover the secrets of Chinese fireworks
6.
Salute (pyrotechnics)
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In pyrotechnics, a salute is an explosive device primarily designed to make a loud bang with a very intense flash of light. Salutes are made from flash powder, most commonly a 70,30 mixture of potassium perchlorate, titanium flakes may be added as a special effect 5% to the total mix. A salute may be fired on the ground or launched from a mortar as a shell or, Salutes are one of the more dangerous type of fireworks. Mortar tubes used to launch aerial salute shells in commercial firework displays vary from 1.75 inch to 8 inch diameter, the shells they fire can come in ball or canister form. Ground salutes most commonly come in a paper tube but may also come round as a or triangle as a, Salutes may have aluminum, antimony, titanium or other metals. Flash Salutes are much louder when they are 2/3 full of composition allowing for 100% heat/gas conversion/expansion before combustion, all commercial salutes are made this way for this reason. The most common aluminum is Dark Pyro Al or Bright Pyro Al, Dark Als preferred are Dark German Al or Indian Blackhead Al -3 Micron. Both are known for being the most violent/reactive/explosive, Bright Flake Aluminum -325 mesh is a cheaper alternative but does not burn as fast and is not as explosive. Flake Aluminum is the only al used for flash powder, all ground salutes over 50 mg and air salutes over 130 mg are restricted by the United States Consumer Product Safety Commission and the Child Protection Act of 1966. 99% of all ground and aerial are made with flash powder. These salutes were called Cannon Crackers, flash powder is significantly more destructive than black powder. Black powder has a slow burn rate to push objects within the blast radius where as flash powder totally destroys anything within its range. This is why gunpowder is the standard for firearms and why black powder salutes need heavy confinement to work, though news reporters and black-market dealers compare the M-80 to a 1/4 stick of dynamite, the two are nowhere close. For reference, a stick of dynamite contains over 10 times more explosive material than an M-80. Detonation and deflagration is what separates high from low explosive, all salutes have a significantly slower burn rate than high explosives such as nitroglycerin, c4, tannerite, etc. Flash powder is a low explosive while ranking the highest explosive used in pyrotechnics, cherry Bombs 1/2 to 5/8 Inner Diameter 3/4 to 1 Outer Diameter Color, Great American Firecrackers posters reveal they came in just about every color but red was still most common. 1 Gram of flash Also known as kraft salutes, these are made of paper cup sets, coated with layers of sawdust and animal hide glue. The process of coating cherry bombs to make them round is called panning, the glued casings are tumbled in a rotating machine with sawdust while sodium silicate solution is slowly added
7.
Cherry bomb
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A cherry bomb is an approximately spherical exploding firework. Cherry bombs range in size from three-quarters of an inch to one, an ignition fuse is inserted into a hole drilled into the hardened sawdust sphere, all the way down to reach the explosive composition. The fuse extends outside the sphere approximately one to one and a half inches, once the fuse is ignited, it takes about three to four and a half seconds to reach the explosive composition and initiate explosion of the firework. The color of the exterior varies, depending on the manufacturer. These original spherical salutes were powerful enough to cause a safety concern. They were banned in the USA in 1966, by the federal Child Safety Act of 1966, historically, these globe salutes and cherry bombs were made in two halves. One half was filled with powder and the half was glued in place on top of it. This left an air-gap which created a louder bang when the case ruptured, another source says they were originally charged with 5 to 10 times the amount of explosive composition a standard inch-and-a-half paper firecracker had. Cherry Bomb was the first popular single from the album of the band The Runaways. It remains their best-selling single, and is ranked 52nd on VH1s 100 Greatest Hard Rock Songs, the Irish band Ash included a song named Cherry Bomb on their 2001 album Free All Angels. The Whos drummer Keith Moon was famous for playing practical jokes involving cherry bombs during the tours during the 1960s onward. According to a biographer, he bought his first 500 cherry bombs in 1965 and he later progressed to M-80s and even dynamite. They are also used by a number of characters in the The Simpsons, Bart vs. the Space Mutants, in the seventeenth episode of the first season of Boy Meets World, titled The Fugitive, Shawn Hunter blows up a United States mailbox with a cherry bomb. In That 70s Show episode 18, titled The Trials of Michael Kelso, singer and actress Kylie Minogue, wrote and recorded a song Cherry Bomb for her Mexican edition of 2007 album X and as B-side to singles In My Arms and Wow. In 2015, Tyler, The Creator released an album titled Cherry Bomb, Cherry Bomb is the name of a group students part of student Association N. S. Z. V. De Loefbijter in Nijmegen, The Netherlands, in Green Days Revolution Radio, a lyric goes Give me cherry bombs and gasoline. Salute M-80 Glasspack - an automotive muffler, often known by its trademark name
8.
M-80 (explosive)
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M-80s are an American class of large powerful firecrackers, sometimes called salutes. M-80s were originally made in the early 20th century by the U. S. military to simulate explosives or artillery fire, later, the tubes often hold approximately 2½–3 grams of pyrotechnic flash powder, many sources state that an M-80 carries 3 grams of powder. M-80s are not authorized under the law, thus making importation, possession, transportation, firecrackers, including the M-80, can be purchased from Native Reserves in Canada, as they have different governing laws. In 1966, M-80s and cherry bombs were restricted by the United States Consumer Product Safety Commission and those holding a federal explosives license, which can be obtained and is issued by the local ATF authorities may potentially be allowed to purchase M-80s. Federal and state officials sometimes distribute them to farmers to scare away wildlife encroaching on their crops and these firecrackers most commonly have a small capsule with up to 50 mg of powder and a fuse in it. Surrounding the capsule is plaster or a material, and finally a red tube. Because of the size of these firecrackers, buyers are occasionally deceived into thinking that the tube is full. Also the fuse, at times, protrudes from the ends of these firecrackers, genuine M-80s have paper endcaps, and contain 50–60 times more powder. Contrary to urban legend, an M-80 that contains 3,000 mg of powder is not equivalent to a quarter-stick of dynamite. Dynamite generally contains a stable nitroglycerin based high explosive, whereas M-80s or any kind of firecracker contains a low explosive powder. Some illicits, however, contain, or were reported to contain, small amounts of picric acid, cases of documented injuries and accidents accompanied civilian M-80 use during the 1950s and 1960s, and still occur, as M-80s are still produced and sold to the public. There have been documented cases of losing their fingers or hands. John Donner, A Professionals Guide to Pyrotechnics, Understanding and Making Exploding Fireworks, Paladin Press,1997
9.
Firecracker
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A firecracker is a small explosive device primarily designed to produce a large amount of noise, especially in the form of a loud bang, any visual effect is incidental to this goal. They have fuses, and are wrapped in a paper casing to contain the explosive compound. Firecrackers, along with fireworks, originated in China, the predecessor of the firecracker was a type of heated bamboo, used as early as 200 BC, that exploded when heated continuously. The Chinese name for firecrackers, baozhu, literally means exploding bamboo, after the invention of gunpowder, gunpowder firecrackers had a shape that resembled bamboo and produced a similar sound, so the name exploding bamboo was retained. In traditional Chinese culture, firecrackers were used to scare off evil spirits, Firecrackers are generally made of cardboard or plastic, with flash powder or black powder as the propellant. This is not always the case, however, anything from match heads to lighter fluid have been used successfully in making firecrackers. The key to loud firecrackers, however, although in part lying in the propellant substance, is pressure, the entire firecracker must be very tightly packed in order for it to work best. Flash powder, however, does not need to be packed tightly, james Dyer Ball, in his book Things Chinese, has a detailed description about the process and material used for making firecrackers at the end of the 19th century. The bamboo paper was cut into strips of 14 inches long and 1⁄3 inch wide, laid on a table, the firecracker tubes were made from pieces of straw paper wrapped around iron rods of various diameters and then tightened with a special tool. In Wales the slang term for a firecracker, typically used on Guy Fawkes Night, is a jacky-jumper, Firecrackers, as well as other types of explosives, are subject to various laws in many countries, although firecrackers themselves are not usually considered illegal contraband material. The use of firecrackers, although a part of celebration, has over the years led to many injuries. These rules also require a permit from the government, as well as any relevant local bodies such as maritime or aviation authorities and hospitals, schools. Canada — Firecrackers are not authorized under the Explosives Act, thus making importation, possession, transportation, storage, or manufacturing illegal in Canada. It later came out that the children inside the tent had actually been smoking and, Fireworks are still legal to buy for anyone 18 years of age or over. Mainland China — As of 2008, most urban areas in mainland China permit firecrackers, in the first three days of the traditional New Year, it is a tradition that people compete with each other by playing with firecrackers. However, many urban areas banned them in the 1990s, for example, they were banned in Beijings urban districts from 1993 to 2005. In 2004,37 people were killed in a stampede when four million people gathered for a rumored Lantern Festival firework display in nearby Miyun, since the ban was lifted, the firecracker barrage has been tremendous. An unusual feature is that residents in major cities look down on street-level fireworks from their tower blocks
10.
Cap gun
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A cap gun, cap pistol, or cap rifle is a toy gun that creates a loud sound simulating a gunshot and a puff of smoke when a small percussion cap is exploded. Cap guns were made of cast iron, but after World War II were made of zinc alloy. Some are arranged in rings of eight or twelve. There are also single caps, roll caps, and disk caps, cap guns first appeared following the end of the American Civil War in the mid-1860s, when firearms companies experimented with toy guns in order to stay in business. Cap guns became popular when the heroes of cinema and television rode through the West ridding the territories of villains. Many cap guns were named after or endorsed by leading matinee idols like Roy Rogers, Gene Autry, Hopalong Cassidy, The Lone Ranger, Tonto, Dale Evans, Marshal Matt Dillon, children all over the world emulated their heroes and collected and played with these toy guns. There were many types of cap guns, including guns from small Derringers, to larger rifles, one of the last famous ones to sell widely was a toy rifle named after the television show, The Rifleman, which aired from 1958 through early 1963. Other shows lasted longer, such as Gunsmoke, but those did not have as much kid-appeal as the shows. The pistols generally were in 3 styles, the semi-automatic, the revolver and the mock-revolver that looked like a regular revolver, the circular cap was placed into the 2-piece bullet and then when the gun was loaded and fired, it seemed more realistic. When the gun was fired, the spring pressure shot the plastic out of the end of the barrel. Eventually Mattel also came out with a model called Shootin Shells. Mattel produced an automatic firing cap weapon styled after the Thompson submachine gun, pulling back on a slide, which simulated the charging handle of the real Thompson, prepared the gun for firing by tensioning a spring. When the trigger was pulled the power would drive the mechanism. It was made initially for a Dick Tracy line of toys, then camouflaged for a Green Beret Guerilla Fighter line of weapons, ring cap guns are usually modeled after revolver pistols, with the cap ring placed in the cylinder section of the toy gun. Strip or paper cap guns use the cap strip in lieu of the cap ring. As in the style of gun, each pull of the trigger advances the cap strip forward, pulls back the hammer to the point where it releases. Potato or spud guns occasionally use a cap to provide a burst of gas to fire the projectile, one design employs a small reusable metal cartridge which has a recess for a cap at one end and a small drilling through to the other end, which holds the potato. Due to the low energy contained in a cap and the poor seal around the cartridge
11.
Flash (photography)
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A flash is a device used in photography producing a flash of artificial light at a color temperature of about 5500 K to help illuminate a scene. A major purpose of a flash is to illuminate a dark scene, other uses are capturing quickly moving objects or changing the quality of light. Flash refers either to the flash of light itself or to the flash unit discharging the light. Most current flash units are electronic, having evolved from single-use flashbulbs, modern cameras often activate flash units automatically. Flash units are built directly into a camera. Some cameras allow separate flash units to be mounted via an accessory mount bracket. In professional studio equipment, flashes may be large, standalone units, or studio strobes, studies of magnesium by Bunsen and Roscoe in 1859 showed that burning this metal produced a light with similar qualities to daylight. The potential application to photography inspired Edward Sonstadt to investigate methods of manufacturing magnesium so that it would burn reliably for this use and he applied for patents in 1862 and by 1864 had started the Manchester Magnesium Company with Edward Mellor. It also had the benefit of being a simpler and cheaper process than making round wire, mather was also credited with the invention of a holder for the ribbon, which formed a lamp to burn it in. The packaging also implies that the ribbon was not necessarily broken off before being ignited. An alternative to ribbon was flash powder, a mixture of powder and potassium chlorate, introduced by its German inventors Adolf Miethe. A measured amount was put into a pan or trough and ignited by hand, producing a brilliant flash of light, along with the smoke. This could be an activity, especially if the flash powder was damp. An electrically triggered flash lamp was invented by Joshua Lionel Cowen in 1899 and his patent describes a device for igniting photographers’ flash powder by using dry cell batteries to heat a wire fuse. Variations and alternatives were touted from time to time and a few found a measure of success in the marketplace, especially for amateur use. The use of powder in an open lamp was replaced by flashbulbs, magnesium filaments were contained in bulbs filled with oxygen gas. Manufactured flashbulbs were first produced commercially in Germany in 1929, such a bulb could only be used once, and was too hot to handle immediately after use, but the confinement of what would otherwise have amounted to a small explosion was an important advance. A later innovation was the coating of flashbulbs with a film to maintain bulb integrity in the event of the glass shattering during the flash
12.
Photography
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Typically, a lens is used to focus the light reflected or emitted from objects into a real image on the light-sensitive surface inside a camera during a timed exposure. With an electronic sensor, this produces an electrical charge at each pixel. A negative image on film is used to photographically create a positive image on a paper base, known as a print. The word photography was created from the Greek roots φωτός, genitive of φῶς, light and γραφή representation by means of lines or drawing, several people may have coined the same new term from these roots independently. Johann von Maedler, a Berlin astronomer, is credited in a 1932 German history of photography as having used it in an article published on 25 February 1839 in the German newspaper Vossische Zeitung. Both of these claims are now widely reported but apparently neither has ever been confirmed as beyond reasonable doubt. Credit has traditionally given to Sir John Herschel both for coining the word and for introducing it to the public. Photography is the result of combining several technical discoveries, later Greek mathematicians Aristotle and Euclid also independently described a pinhole camera in the 5th and 4th centuries BCE. Daniele Barbaro described a diaphragm in 1566, wilhelm Homberg described how light darkened some chemicals in 1694. The fiction book Giphantie, published in 1760, by French author Tiphaigne de la Roche, the discovery of the camera obscura that provides an image of a scene dates back to ancient China. Leonardo da Vinci mentions natural camera obscura that are formed by dark caves on the edge of a sunlit valley, a hole in the cave wall will act as a pinhole camera and project a laterally reversed, upside down image on a piece of paper. So the birth of photography was primarily concerned with inventing means to capture, renaissance painters used the camera obscura which, in fact, gives the optical rendering in color that dominates Western Art. The camera obscura literally means dark chamber in Latin and it is a box with a hole in it which allows light to go through and create an image onto the piece of paper. Around the year 1800, British inventor Thomas Wedgwood made the first known attempt to capture the image in a camera obscura by means of a light-sensitive substance and he used paper or white leather treated with silver nitrate. The shadow images eventually darkened all over, the first permanent photoetching was an image produced in 1822 by the French inventor Nicéphore Niépce, but it was destroyed in a later attempt to make prints from it. Niépce was successful again in 1825, in 1826 or 1827, he made the View from the Window at Le Gras, the earliest surviving photograph from nature. Because Niépces camera photographs required a long exposure, he sought to greatly improve his bitumen process or replace it with one that was more practical. With an eye to eventual commercial exploitation, the partners opted for total secrecy, Daguerres efforts culminated in what would later be named the daguerreotype process
13.
Potassium perchlorate
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Potassium perchlorate is the inorganic salt with the chemical formula KClO4. Like other perchlorates, this salt is a strong oxidizer although it reacts very slowly with organic substances. It has been used as a rocket propellant, although in that application it has mostly been replaced by the higher performance ammonium perchlorate. KClO4 has the lowest solubility of the alkali metal perchlorates, KClO4 is prepared industrially by treating an aqueous solution of sodium perchlorate with KCl. This single precipitation reaction exploits the low solubility of KClO4, which is about 100 times less than the solubility of NaClO4. It can also be produced by the reaction of perchloric acid with potassium hydroxide, however, KClO4 is an oxidizer in the sense that it exothermically transfers oxygen to combustible materials, greatly increasing their rate of combustion relative to that in air. With sugar, KClO4 yields a low explosive, provided the necessary confinement, otherwise such mixtures simply deflagrate with an intense purple flame characteristic of potassium. Flash compositions used in firecrackers usually consist of a mixture of aluminium powder and this mixture, sometimes called flash powder, is also used in ground and air fireworks. As an oxidizer, potassium perchlorate can be used safely in the presence of sulfur, the greater reactivity of chlorate is typical – perchlorates are kinetically poorer oxidants. Chlorate produces chloric acid, which is unstable and can lead to premature ignition of the composition. Correspondingly, perchloric acid is quite stable, potassium perchlorate can be used as an antithyroid agent used to treat hyperthyroidism, usually in combination with one other medication. This application exploits the similar ionic radius and hydrophilicity of perchlorate, the administration of known goitrogen substances can also be used as a prevention in reducing the bio-uptake of iodine. Perchlorate ions, a common contaminant in the USA due to the aerospace industry, has been shown to reduce iodine uptake. Perchlorate ions are a competitive inhibitor of the process by which iodide, is deposited into thyroid follicular cells. Current regimens for treatment of thyrotoxicosis, when a patient is exposed to sources of Iodine. Prophylaxis with perchlorate containing water at concentrations of 17 ppm, which corresponds to 0, studies of chronically exposed workers though have thus far failed to detect any abnormalities of thyroid function, including the uptake of iodine. This may well be attributable to sufficient daily exposure or intake of healthy Iodine-127 among the workers and the short 8 hr Biological half life of Perchlorate in the body. Perchlorate ion concentrations in a water supply, would need to be much higher
14.
Aluminium powder
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This was originally produced by mechanical means using a stamp mill to create flakes. Subsequently, a process of spraying molten aluminum to create a powder of droplets was developed by E. J. Hall in the 1920s, the resulting powder might then be processed further in a ball mill to flatten it into flakes for use as a coating or pigment. Aluminium powder is non toxic and is not harmful unless injected directly in a blood vessel such as the aorta. Aluminum powder, if breathed in, it is not particularly harmful, cosmetic colorant pyrotechnic in paints as metallic silver pigment Fingerprint Powder Rocket and missile Fuel thermite Depending on the usage, the powder is either coated or uncoated
15.
Sulfur
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Sulfur or sulphur is a chemical element with symbol S and atomic number 16. It is abundant, multivalent, and nonmetallic, under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a yellow crystalline solid at room temperature. Chemically, sulfur reacts with all elements except for gold, platinum, iridium, tellurium, though sometimes found in pure, native form, sulfur usually occurs as sulfide and sulfate minerals. Being abundant in native form, sulfur was known in ancient times, being mentioned for its uses in ancient India, ancient Greece, China, in the Bible, sulfur is called brimstone. Today, almost all elemental sulfur is produced as a byproduct of removing sulfur-containing contaminants from natural gas, the greatest commercial use of the element is the production of sulfuric acid for sulfate and phosphate fertilizers, and other chemical processes. The element sulfur is used in matches, insecticides, and fungicides, many sulfur compounds are odoriferous, and the smells of odorized natural gas, skunk scent, grapefruit, and garlic are due to organosulfur compounds. Hydrogen sulfide gives the characteristic odor to rotting eggs and other biological processes, sulfur is an essential element for all life, but almost always in the form of organosulfur compounds or metal sulfides. Three amino acids and two vitamins are organosulfur compounds, many cofactors also contain sulfur including glutathione and thioredoxin and iron–sulfur proteins. Disulfides, S–S bonds, confer mechanical strength and insolubility of the keratin, found in outer skin, hair. Sulfur is one of the chemical elements needed for biochemical functioning and is an elemental macronutrient for all organisms. Sulfur is derived from the Latin word sulpur, which was Hellenized to sulphur, the spelling sulfur appears toward the end of the Classical period. In 12th-century Anglo-French, it was sulfre, in the 14th century the Latin ph was restored, for sulphre, the parallel f~ph spellings continued in Britain until the 19th century, when the word was standardized as sulphur. Sulfur was the form chosen in the United States, whereas Canada uses both, the IUPAC adopted the spelling sulfur in 1990, as did the Nomenclature Committee of the Royal Society of Chemistry in 1992, restoring the spelling sulfur to Britain. Sulfur forms polyatomic molecules with different chemical formulas, the best-known allotrope being octasulfur, cyclo-S8. The point group of cyclo-S8 is D4d and its dipole moment is 0 D. Octasulfur is a soft, bright-yellow solid that is odorless and it melts at 115.21 °C, boils at 444.6 °C and sublimes easily. At 95.2 °C, below its melting temperature, cyclo-octasulfur changes from α-octasulfur to the β-polymorph, the structure of the S8 ring is virtually unchanged by this phase change, which affects the intermolecular interactions. At higher temperatures, the viscosity decreases as depolymerization occurs, molten sulfur assumes a dark red color above 200 °C
16.
Potassium chlorate
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Potassium chlorate is a compound containing potassium, chlorine and oxygen atoms, with the molecular formula KClO3. In its pure form, it is a crystalline substance. It is the most common chlorate in industrial use, on the industrial scale, potassium chlorate is produced by the Liebig process, passing chlorine into hot calcium hydroxide, subsequently adding potassium chloride. The low solubility of KClO3 in water causes the salt to conveniently isolate itself from the mixture by simply precipitating out of solution. It continues in that application, where not supplanted by potassium perchlorate, chlorate-based propellants are more efficient than traditional gunpowder and are less susceptible to damage by water. However, they can be unstable in the presence of sulfur or phosphorus and are much more expensive. Chlorate propellants must be used only in equipment designed for them, potassium chlorate, often in combination with silver fulminate, is used in trick noise-makers known as crackers, snappers, pop-its, or bang-snaps, a popular type of novelty firework. Another application of potassium chlorate is as the oxidizer in a composition such as that used in smoke grenades. Since 2005, a cartridge with potassium chlorate mixed with lactose, potassium chlorate is often used in high school and college laboratories to generate oxygen gas. It is a far cheaper source than a pressurized or cryogenic oxygen tank, potassium chlorate readily decomposes if heated while in contact with a catalyst, typically manganese dioxide. Thus, it may be placed in a test tube. If the test tube is equipped with a stopper and hose. Molten potassium chlorate is a powerful oxidizer and spontaneously reacts with many common materials such as sugar. Explosions have resulted from liquid chlorates spattering into the latex or PVC tubes of oxygen generators, impurities in potassium chlorate itself can also cause problems. When working with a new batch of potassium chlorate, it is advisable to take a small sample, contamination may cause this small quantity to explode, indicating that the chlorate should be discarded. Potassium chlorate is used in chemical oxygen generators, employed as oxygen-supply systems of e. g. aircraft, space stations, and submarines, a fire on the space station Mir was also traced to this substance. The decomposition of potassium chlorate was also used to provide the oxygen supply for limelights, potassium chlorate is used also as a pesticide. In Finland it was sold under trade name Fegabit, in schools, molten potassium chlorate is used in the dramatic screaming jelly babies demonstration
17.
Flare (countermeasure)
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A flare or decoy flare is an aerial infrared countermeasure used by a plane or helicopter to counter an infrared homing surface-to-air missile or air-to-air missile. Flares are commonly composed of a composition based on magnesium or another hot-burning metal. The aim is to make the infrared-guided missile seek out the signature from the flare rather than the aircrafts engines. In contrast to radar-guided missiles, IR-guided missiles are very difficult to find as they approach aircraft and they do not emit detectable radar, and they are generally fired from a rear visual-aspect, directly toward the engines. In most cases, pilots have to rely on their wingmen to spot the missiles smoke trail, more advanced electro-optical systems can detect missile launches automatically from the distinct thermal emissions of a missiles rocket motor. The aircraft would then pull away at an angle from the flare. Optimally, the seeker head is then confused by this change in temperature and flurry of new signatures. The most modern IR-guided missiles have sophisticated on-board electronics that help discriminate between flares and targets, reducing the effectiveness of countermeasures, consequently, flare dispensers are now fitted to helicopters. Indeed almost all of the UKs helicopters, whether they are transport or attack models, are equipped with flare dispenser or missile approach warning systems, similarly, the US armed forces have adopted defensive technology on their helicopters. This caused concerns in some European countries, which proceeded to ban such aircraft from landing at their airports, a flare goes through three main stages, ignition, deployment, and decoying. Most flares, like the MJU-27A/B flares, must be kept in a storage compartment before deployment. These flares, known as flares, are made of special materials that ignite when they come in contact with the air. This is a safety and convenience factor, since attempting to ignite a flare inside the fuselage, flares are most commonly gravity-fed from a dispenser inside the aircrafts fuselage. These dispensers can be programmed by the pilot or ground crew to dispense flares in short intervals, one at a time, long intervals, or in clusters. Most currently used flares are of the variety, and thus the dispensers do not have to ignite. With pyrotechnic flares, a lanyard automatically pulls off a friction cap covering the end of the flare as it falls from the dispenser. A friction surface inside the cap rubs against the end of the flare. Flares burn at thousands of degrees, which is hotter than the exhaust of a jet engine
18.
Stun grenade
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A stun grenade, also known as a flash grenade, flashbang or sound bomb or Braquo, is a non-lethal explosive device used to temporarily disorient an enemys senses. It is designed to produce a flash of light and an intensely loud bang of greater than 170 decibels without causing permanent injury. It was first used by the British Armys SAS in the late 1970s, the flash produced momentarily activates all photoreceptor cells in the eye, making vision impossible for approximately five seconds, until the eye restores itself to its normal, unstimulated state. An afterimage will also be visible for a time, impairing the victims ability to aim with precision. The loud blast is meant to temporary loss of hearing. The concussive blast of the detonation can still injure, and the heat created can ignite flammable materials such as fuel, the fires that occurred during the Iranian Embassy siege in London were caused by stun grenades. The filler consists of a pyrotechnic metal-oxidant mix of magnesium or aluminum, although stun grenades are usually designed to be non-lethal, several injuries and deaths have been officially attributed to their use. The flashbang grenades police used in the set the home on fire. Police said they were no one was inside, and so, at first. Smalley and Weiss died of smoke inhalation and her family eventually won a $1.6 million civil suit against the city. In February 2010, police in Minneapolis, Minnesota, raided the apartment of Rickia Russell looking for drugs, while Russell was eating dinner with her boyfriend, police threw a flashbang grenade after breaching the door. The exploding flashbang gave Rickia 3rd degree burns on both calves, and burns to her head, no drugs were found in Russells apartment and the Minneapolis City Council agreed to pay $1 million in damages. In January 2011, a California man named Rogelio Serrato died of smoke inhalation after a grenade launched by a police SWAT team ignited a fire in his home. The man was believed to have been hiding in the attic when the fire broke out, in February 2011, a North Carolina SWAT police officer was injured at his home when a stun grenade accidentally detonated while he was attempting to secure his equipment. He underwent emergency surgery, but later died of his injuries, in January 2014, a man was severely injured during rioting caused by the 2014 Ukrainian revolution after he attempted to pick up a live, undetonated stun grenade. The grenade detonated seconds before he could reach it, the explosion caused damage to his right hand and arm, leading to the loss of most of his fingers, as well as heavy blood loss. As of February 2014, the condition is unknown. However, a video of it has been uploaded to LiveLeak, on May 28,2014, a 19-month-old baby boys face was severely burned and mutilated when a stun grenade was thrown into his playpen by a SWAT team looking for drugs in a Cornelia, Georgia home
19.
Magic (illusion)
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Magic is one of the oldest performing arts in the world in which audiences are entertained by staged tricks or illusions of seemingly impossible or supernatural feats using natural means. These feats are called magic tricks, effects, or illusions, the term magic etymologically derives from the Greek word mageia. In ancient times, Greeks and Persians had been at war for centuries, ritual acts of Persian priests came to be known as mageia, and then magika—which eventually came to mean any foreign, unorthodox, or illegitimate ritual practice. The first book containing explanations of magic tricks appeared in 1584, during the 17th century, many similar books were published that described magic tricks. Until the 18th century, magic shows were a source of entertainment at fairs. A founding figure of modern entertainment magic was Jean Eugène Robert-Houdin, John Henry Anderson was pioneering the same transition in London in the 1840s. Towards the end of the 19th century, large magic shows permanently staged at big theatre venues became the norm, as a form of entertainment, magic easily moved from theatrical venues to television magic specials. Performances that modern observers would recognize as conjuring have been practiced throughout history, for many recorded centuries, magicians were associated with the devil and the occult. During the 19th and 20th centuries, many stage magicians even capitalized on this notion in their advertisements. The same level of ingenuity that was used to produce famous ancient deceptions such as the Trojan Horse would also have used for entertainment. They were also used by the practitioners of various religions and cults from ancient times onwards to frighten uneducated people into obedience or turn them into adherents, however, the profession of the illusionist gained strength only in the 18th century, and has enjoyed several popular vogues since. Opinions vary among magicians on how to categorize a given effect, Magicians may pull a rabbit from an empty hat, make something seem to disappear, or transform a red silk handkerchief into a green silk handkerchief. Magicians may also destroy something, like cutting a head off, other illusions include making something appear to defy gravity, making a solid object appear to pass through another object, or appearing to predict the choice of a spectator. Many magical routines use combinations of effects, one of the earliest books on the subject is Gantzionys work of 1489, Natural and Unnatural Magic, which describes and explains old-time tricks. Among the tricks discussed were sleight-of-hand manipulations with rope, paper, at the time, fear and belief in witchcraft was widespread and the book tried to demonstrate that these fears were misplaced. All obtainable copies were burned on the accession of James I in 1603 and it began to reappear in print in 1651. In the early 18th century, as belief in witchcraft was waning, a notable figure in this transition was the English showman, Isaac Fawkes, who began to promote his act in advertisements from the 1720s – he even claimed to have performed for King George II. He throws up a Pack of Cards, and causes them to be living birds flying about the room and he causes living Beasts, Birds, and other Creatures to appear upon the Table
20.
Movie theater
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A movie theater or movie theatre is a venue, usually a building, that contains an auditorium for viewing films, for entertainment. Most, but not all, movie theaters are commercial operations catering to the general public, Some movie theaters, however, are operated by non-profit organizations or societies which charge members a membership fee to view films. The film is projected with a projector onto a large projection screen at the front of the auditorium while the dialogue, sounds. Since the 1970s, subwoofers have used for low-pitched sounds. In the 2010s, most movie theaters are equipped for digital cinema projection, removing the need to create, a great variety of films are shown at cinemas, ranging from animated films for children, blockbusters for general audiences and documentaries for patrons who are interested in non-fiction topics. The smallest movie theaters have a viewing room with a single screen. In the 2010s, most movie theaters have multiple screens, the largest theater complexes, which are called multiplexes—a design developed in the U. S. in the 1960s—have up to 25 screens. The audience members sit on padded seats which in most theaters are set up on a sloped floor. Movie theaters typically sell soft drinks, popcorn and candy and some theaters also sell hot fast food, in some jurisdictions, movie theaters are licensed to sell alcoholic drinks. A movie theater may also be referred to as a theatre, movie house, film house. In the US, theater has long been the preferred spelling, while in the UK, Canada, the latter terms, as well as their derivative adjectives cinematic and kinematic, ultimately derive from Greek κινῆμα, κινήματος —movement, motion. In the countries where those terms are used, the theatre is usually reserved for live performance venues. Colloquial expressions, mostly applied to motion pictures and motion picture theaters collectively, include the silver screen, specific to North American term is the movies, while specific terms in the UK are the pictures, the flicks and for the facility itself the flea pit. A screening room is a theater, often a private one. Open air place in ancient times for viewing spectacles and plays, the term theater comes from the Old French word theatre, from the 12th century and. The use of the theatre to mean a building where plays are shown dates from the 1570s in the English language. The earliest precursors to movies were magic lantern shows, magic lanterns used a glass lens, a shutter and a powerful lamp to project images from glass slides onto a white wall or screen. The invention of the Argand lamp in the 1790s, limelight in the 1820s, the magic lantern could project rudimentary moving images, which was achieved by the use of various types of mechanical slides
21.
Theatre
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The performers may communicate this experience to the audience through combinations of gesture, speech, song, music, and dance. Elements of art, such as painted scenery and stagecraft such as lighting are used to enhance the physicality, presence, the specific place of the performance is also named by the word theatre as derived from the Ancient Greek θέατρον, itself from θεάομαι. Modern theatre, broadly defined, includes performances of plays and musical theatre, there are connections between theatre and the art forms of ballet, opera and various other forms. The city-state of Athens is where western theatre originated, participation in the city-states many festivals—and mandatory attendance at the City Dionysia as an audience member in particular—was an important part of citizenship. The Greeks also developed the concepts of dramatic criticism and theatre architecture, Actors were either amateur or at best semi-professional. The theatre of ancient Greece consisted of three types of drama, tragedy, comedy, and the satyr play, the origins of theatre in ancient Greece, according to Aristotle, the first theoretician of theatre, are to be found in the festivals that honoured Dionysus. The performances were given in semi-circular auditoria cut into hillsides, capable of seating 10, the stage consisted of a dancing floor, dressing room and scene-building area. Since the words were the most important part, good acoustics, the actors wore masks appropriate to the characters they represented, and each might play several parts. Athenian tragedy—the oldest surviving form of tragedy—is a type of dance-drama that formed an important part of the culture of the city-state. Having emerged sometime during the 6th century BCE, it flowered during the 5th century BCE, no tragedies from the 6th century BCE and only 32 of the more than a thousand that were performed in during the 5th century BCE have survived. We have complete texts extant by Aeschylus, Sophocles, and Euripides, the origins of tragedy remain obscure, though by the 5th century BCE it was institution alised in competitions held as part of festivities celebrating Dionysus. As contestants in the City Dionysias competition playwrights were required to present a tetralogy of plays, the performance of tragedies at the City Dionysia may have begun as early as 534 BCE, official records begin from 501 BCE, when the satyr play was introduced. More than 130 years later, the philosopher Aristotle analysed 5th-century Athenian tragedy in the oldest surviving work of dramatic theory—his Poetics, Athenian comedy is conventionally divided into three periods, Old Comedy, Middle Comedy, and New Comedy. Old Comedy survives today largely in the form of the surviving plays of Aristophanes. New Comedy is known primarily from the papyrus fragments of Menander. Aristotle defined comedy as a representation of people that involves some kind of blunder or ugliness that does not cause pain or disaster. In addition to the categories of comedy and tragedy at the City Dionysia, finding its origins in rural, agricultural rituals dedicated to Dionysus, the satyr play eventually found its way to Athens in its most well-known form. Satyrs themselves were tied to the god Dionysus as his loyal companions, often engaging in drunken revelry
22.
Special effect
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Special effects are illusions or visual tricks used in the film, television, theatre, video game, and simulator industries to simulate the imagined events in a story or virtual world. Special effects are divided into the categories of optical effects. Mechanical effects are usually accomplished during the live-action shooting and this includes the use of mechanized props, scenery, scale models, animatronics, pyrotechnics and atmospheric effects, creating physical wind, rain, fog, snow, clouds, etc. Making a car appear to drive by itself and blowing up a building are examples of mechanical effects, mechanical effects are often incorporated into set design and makeup. For example, a set may be built with doors or walls to enhance a fight scene. An optical effect might be used to place actors or sets against a different background, since the 1990s, computer generated imagery has come to the forefront of special effects technologies. It gives filmmakers greater control, and allows many effects to be accomplished safely and convincingly and—as technology improves—at lower costs. As a result, many optical and mechanical effects techniques have been superseded by CGI, in 1857, Oscar Rejlander created the worlds first special effects movie by combining different sections of 30 negatives into a single image. In 1895, Alfred Clark created what is accepted as the first-ever motion picture special effect. While filming a reenactment of the beheading of Mary, Queen of Scots, as the executioner brought the axe above his head, Clark stopped the camera, had all of the actors freeze, and had the person playing Mary step off the set. He placed a Mary dummy in the place, restarted filming. Techniques like these would dominate the production of special effects for a century and it wasnt only the first use of trickery in cinema, it was also the first type of photographic trickery only possible in a motion picture, i. e. the stop trick. Georges Méliès accidentally discovered the same stop trick, according to Méliès, his camera jammed while filming a street scene in Paris. When he screened the film, he found that the trick had caused a truck to turn into a hearse, pedestrians to change direction. Because of his ability to manipulate and transform reality with the cinematograph. From 1910 to 1920, the innovations in special effects were the improvements on the matte shot by Norman Dawn. With the original matte shot, pieces of cardboard were placed to block the exposure of the film, Dawn combined this technique with the glass shot. Rather than using cardboard to block certain areas of the film exposure, from the partially exposed film, a single frame is then projected onto an easel, where the matte is then drawn
23.
Stoichiometry
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Stoichiometry /ˌstɔɪkiˈɒmᵻtri/ is the calculation of relative quantities of reactants and products in chemical reactions. This means that if the amounts of the reactants are known. Conversely, if one reactant has a quantity and the quantity of product can be empirically determined. This is illustrated in the image here, where the equation is. Here, one molecule of methane reacts with two molecules of gas to yield one molecule of carbon dioxide and two molecules of water. Stoichiometry measures these quantitative relationships, and is used to determine the amount of products/reactants that are produced/needed in a given reaction, describing the quantitative relationships among substances as they participate in chemical reactions is known as reaction stoichiometry. In the example above, reaction stoichiometry measures the relationship between the methane and oxygen as they react to form carbon dioxide and water. Gas stoichiometry deals with reactions involving gases, where the gases are at a temperature, pressure. For gases, the ratio is ideally the same by the ideal gas law. In practice, due to the existence of isotopes, molar masses are used instead when calculating the mass ratio, the term stoichiometry was first used by Jeremias Benjamin Richter in 1792 when the first volume of Richters Stoichiometry or the Art of Measuring the Chemical Elements was published. The term is derived from the Greek words στοιχεῖον stoicheion element, in patristic Greek, the word Stoichiometria was used by Nicephorus to refer to the number of line counts of the canonical New Testament and some of the Apocrypha. In general, chemical reactions combine in definite ratios of chemicals, since chemical reactions can neither create nor destroy matter, nor transmute one element into another, the amount of each element must be the same throughout the overall reaction. Chemical reactions, as unit operations, consist of simply a very large number of elementary reactions. As the reacting molecules consist of a set of atoms in an integer ratio. A reaction may consume more than one molecule, and the number counts this number, defined as positive for products. Different elements have a different atomic mass, and as collections of atoms, molecules have a definite molar mass. By definition, carbon-12 has a mass of 12 g/mol. The mass ratios can be calculated by dividing each by the total in the whole reaction, Elements in their natural state are mixtures of isotopes of differing mass, thus atomic masses and thus molar masses are not exactly integers
24.
Triboelectric
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The triboelectric effect is a type of contact electrification in which certain materials become electrically charged after they come into frictional contact with a different material. Rubbing glass with fur, or a plastic comb through the hair, most everyday static electricity is triboelectric. The polarity and strength of the charges produced differ according to the materials, surface roughness, temperature, strain, the triboelectric effect is not very predictable, and only broad generalizations can be made. Amber, for example, can acquire a charge by contact. This property was first recorded by Thales of Miletus, the word electricity is derived from William Gilberts initial coinage, electra, which originates in the Greek word for amber, ēlektron. The prefix tribo- refers to ‘friction’, as in tribology, other examples of materials that can acquire a significant charge when rubbed together include glass rubbed with silk, and hard rubber rubbed with fur. Physical separation of materials that are adhered together results in friction between the materials, thus, a material can develop a positive or negative charge that dissipates after the materials separate. Johan Carl Wilcke published the first triboelectric series in a 1757 paper on static charges, materials are often listed in order of the polarity of charge separation when they are touched with another object. A material towards the bottom of the series, when touched to a material near the top of the series, the farther away two materials are from each other on the series, the greater the charge transferred. Materials near to other on the series may not exchange any charge. This can be caused by rubbing, by contaminants or oxides, lists vary somewhat as to the exact order of some materials, since the relative charge varies for nearby materials. From actual tests, there is little or no difference in charge affinity between metals, probably because the rapid motion of conduction electrons cancels such differences. Although the part tribo- comes from the Greek for rubbing, τρίβω, after coming into contact, a chemical bond is formed between parts of the two surfaces, called adhesion, and charges move from one material to the other to equalize their electrochemical potential. This is what creates the net imbalance between the objects. In addition, some materials may exchange ions of differing mobility, the triboelectric effect is related to friction only because they both involve adhesion. However, the effect is enhanced by rubbing the materials together, as they touch. Surface nano-effects are not well understood, and the atomic force microscope has enabled rapid progress in this field of physics, a person simply walking across a carpet may build up a potential of many thousands of volts, enough to cause a spark one centimeter long or more. Simply removing a nylon shirt or corset can also create sparks, car travel can lead to a build-up of charge on the driver and passengers due to friction between the drivers clothes and the leather or plastic furnishings inside the vehicle
25.
Magnesium
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Magnesium is a chemical element with symbol Mg and atomic number 12. Magnesium is the ninth most abundant element in the universe and it is produced in large, aging stars from the sequential addition of three helium nuclei to a carbon nucleus. When such stars explode as supernovas, much of the magnesium is expelled into the medium where it may recycle into new star systems. Magnesium is the eighth most abundant element in the Earths crust and the fourth most common element in the Earth, making up 13% of the planets mass and it is the third most abundant element dissolved in seawater, after sodium and chlorine. Magnesium occurs naturally only in combination with elements, where it invariably has a +2 oxidation state. The free element can be produced artificially, and is highly reactive, the free metal burns with a characteristic brilliant-white light. The metal is now obtained mainly by electrolysis of magnesium salts obtained from brine, Magnesium is less dense than aluminium, and the alloy is prized for its combination of lightness and strength. Magnesium is the eleventh most abundant element by mass in the body and is essential to all cells. Magnesium ions interact with polyphosphate compounds such as ATP, DNA, hundreds of enzymes require magnesium ions to function. Magnesium compounds are used medicinally as common laxatives, antacids, elemental magnesium is a gray-white lightweight metal, two-thirds the density of aluminium. Magnesium has the lowest melting and the lowest boiling point 1,363 K of all the alkaline earth metals, Magnesium reacts with water at room temperature, though it reacts much more slowly than calcium, a similar group 2 metal. When submerged in water, hydrogen bubbles form slowly on the surface of the metal—though, if powdered, the reaction occurs faster with higher temperatures. Magnesiums reversible reaction with water can be harnessed to store energy, Magnesium also reacts exothermically with most acids such as hydrochloric acid, producing the metal chloride and hydrogen gas, similar to the HCl reaction with aluminium, zinc, and many other metals. Magnesium is highly flammable, especially when powdered or shaved into thin strips, flame temperatures of magnesium and magnesium alloys can reach 3,100 °C, although flame height above the burning metal is usually less than 300 mm. Once ignited, such fires are difficult to extinguish, with combustion continuing in nitrogen, carbon dioxide, Magnesium may also be used as an igniter for thermite, a mixture of aluminium and iron oxide powder that ignites only at a very high temperature. When burning in air, magnesium produces a light that includes strong ultraviolet wavelengths. Magnesium powder was used for illumination in the early days of photography. Later, magnesium filament was used in electrically ignited single-use photography flashbulbs, Magnesium powder is used in fireworks and marine flares where a brilliant white light is required
26.
Potassium nitrate
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Potassium nitrate is a chemical compound with the chemical formula KNO3. It is a salt of potassium ions K+ and nitrate ions NO3−. It occurs as a mineral niter and is a solid source of nitrogen. Potassium nitrate is one of several nitrogen-containing compounds collectively referred to as saltpeter or saltpetre, major uses of potassium nitrate are in fertilizers, tree stump removal, rocket propellants and fireworks. It is one of the constituents of gunpowder and has been used since the Middle Ages as a food preservative. Potassium nitrate, because of its early and global use and production, has many names, by the 15th century, Europeans referred to it as saltpeter and later as nitrate of potash, as the chemistry of the compound was more fully understood. The Arabs called it Chinese snow and it was called Chinese salt by the Iranians/Persians or salt from Chinese salt marshes. Potassium nitrate has a crystal structure at room temperature, which transforms to a trigonal system at 129 °C. Potassium nitrate is soluble in water, but its solubility increases with temperature. The aqueous solution is almost neutral, exhibiting pH6.2 at 14 °C for a 10% solution of commercial powder and it is not very hygroscopic, absorbing about 0. 03% water in 80% relative humidity over 50 days. It is insoluble in alcohol and is not poisonous, it can react explosively with reducing agents and this was used for the manufacture of gunpowder and explosive devices. The terminology used by al-Rammah indicated a Chinese origin for the gunpowder weapons about which he wrote, at least as far back as 1845, Chilean saltpeter deposits were exploited in Chile and California, USA. A major natural source of nitrate was the deposits crystallizing from cave walls. Extraction is accomplished by immersing the guano in water for a day, filtering, traditionally, guano was the source used in Laos for the manufacture of gunpowder for Bang Fai rockets. Perhaps the most exhaustive discussion of the production of material is the 1862 LeConte text. He was writing with the purpose of increasing production in the Confederate States to support their needs during the American Civil War. Since he was calling for the assistance of rural farming communities and he details the French Method, along with several variations, as well as a Swiss method. Many references have been made to a method using only straw and urine, LeConte describes a process using only urine and not dung, referring to it as the Swiss method
27.
Barium nitrate
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Barium nitrate with chemical formula Ba2 is a salt composed of barium and the nitrate ion. Barium nitrate exists as a solid at room temperature. It is soluble in water, and like other soluble compounds, is toxic. It occurs naturally as the rare mineral nitrobarite. Barium nitrates properties make it suitable for use in military applications, including thermite grenades. Barium nitrate is manufactured by one of two processes, the first involves dissolving small chunks of barium carbonate in nitric acid, allowing any iron impurities to precipitate, then filtered, evaporated, and crystallized. The second requires combining barium chloride with a solution of sodium nitrate. Reactions with soluble metal sulfates or sulfuric acid yield barium sulfate, many insoluble barium salts, such as the carbonate, oxalate and phosphate of the metal, are precipitated by similar double decomposition reactions. Barium nitrate is an oxidizer and reacts vigorously with reducing agents. The solid powder, when mixed with other metals such as aluminium or zinc in their finely divided form, or combined with alloys such as aluminium-magnesium. Baratol is a composed of barium nitrate, TNT and binder. Barium nitrate mixed with aluminium powder, a formula for flash powder, is highly explosive and it is mixed with thermite to form Thermate-TH3, used in military thermite grenades. It is also used in the process of barium oxide. Like all soluble barium compounds, barium nitrate is toxic by ingestion or inhalation, symptoms of poisoning include tightness of muscles, vomiting, diarrhea, abdominal pain, muscular tremors, anxiety, weakness, labored breathing, cardiac irregularity, and convulsions. Death may result from cardiac or respiratory failure, and usually occurs a few hours to a few days following exposure to the compound, barium nitrate may also cause kidney damage. Solutions of sulfate salts such as Epsom salts or sodium sulfate may be given as first aid for barium poisoning, inhalation may also cause irritation to the respiratory tract. While skin or eye contact is less harmful than ingestion or inhalation, it can result in irritation, itching, redness
28.
Strontium nitrate
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Strontium nitrate is an inorganic compound with the formula Sr2. This colourless solid is used as a colorant in pyrotechnics and is used as an oxidizer in pyrotechnics. Strontium nitrate is typically generated by the reaction of acid on strontium carbonate. 2 HNO3 + SrCO3 → Sr2 + H2O + CO2, like many other strontium salts, strontium nitrate is used to produce a rich red flame in fireworks and road flares. The oxidizing properties of salt are advantageous in such applications. Strontium nitrate can aid in eliminating and lessening skin irritations, when mixed with glycolic acid, strontium nitrate reduces the sensation of skin irritation significantly better than using glycolic acid alone. It is thus used in electrophysiology experiments, in his short story A Germ Destroyer, Rudyard Kipling refers to strontium nitrate as the main ingredient of the titular fumigant
29.
Nitrate
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Nitrate is a polyatomic ion with the molecular formula NO−3 and a molecular mass of 62.0049 g/mol. Nitrates also describe the functional group RONO2. These nitrate esters are a class of explosives. The anion is the base of nitric acid, consisting of one central nitrogen atom surrounded by three identically bonded oxygen atoms in a trigonal planar arrangement. The nitrate ion carries a charge of −1. This arrangement is used as an example of resonance. Like the isoelectronic carbonate ion, the ion can be represented by resonance structures. A common example of a nitrate salt is potassium nitrate. A rich source of nitrate in the human body comes from diets rich in leafy green foods, such as spinach. NO3- is the active component within beetroot juice and other vegetables. Nitrite and water are converted in the body to nitric oxide, nitrate salts are found naturally on earth as large deposits, particularly of nitratine, a major source of sodium nitrate. Nitrates are found in man-made fertilizers, as a byproduct of lightning strikes in earths nitrogen-oxygen rich atmosphere, nitric acid is produced when nitrogen dioxide reacts with water vapor. Nitrates are mainly produced for use as fertilizers in agriculture because of their solubility and biodegradability. The main nitrate fertilizers are ammonium, sodium, potassium, several million kilograms are produced annually for this purpose. The second major application of nitrates is as oxidizing agents, most notably in explosives where the oxidation of carbon compounds liberates large volumes of gases. Sodium nitrate is used to air bubbles from molten glass. Mixtures of the salt are used to harden some metals. Explosives and table tennis balls are made from celluloid, although nitrites are the nitrogen compound chiefly used in meat curing, nitrates are used in certain specialty curing processes where a long release of nitrite from parent nitrate stores is needed
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Polytetrafluoroethylene
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Polytetrafluoroethylene is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. The best known name of PTFE-based formulas is Teflon by Chemours. Chemours is a spin-off of DuPont Co. which discovered the compound in 1938, PTFE is a fluorocarbon solid, as it is a high-molecular-weight compound consisting wholly of carbon and fluorine. PTFE is hydrophobic, neither water nor water-containing substances wet PTFE, PTFE has one of the lowest coefficients of friction of any solid. PTFE is used as a coating for pans and other cookware. It is very non-reactive, partly because of the strength of carbon–fluorine bonds, where used as a lubricant, PTFE reduces friction, wear and energy consumption of machinery. It is commonly used as a material in surgical interventions. Also, it is employed as coating on catheters, this interferes with the ability of bacteria and other infectious agents to adhere to catheters. PTFE was accidentally discovered in 1938 by Roy Plunkett while he was working in New Jersey for DuPont. Since Plunkett was measuring the amount of gas used by weighing the bottle, he became curious as to the source of the weight and he found the bottles interior coated with a waxy white material that was oddly slippery. Analysis showed that it was polymerized perfluoroethylene, with the iron from the inside of the container having acted as a catalyst at high pressure, Kinetic Chemicals patented the new fluorinated plastic in 1941, and registered the Teflon trademark in 1945. By 1948, DuPont, which founded Kinetic Chemicals in partnership with General Motors, was producing two million pounds of Teflon brand PTFE per year in Parkersburg, West Virginia. In 1954, the wife of French engineer Marc Grégoire urged him to try the material he had been using on fishing tackle on her cooking pans and he subsequently created the first Teflon-coated, non-stick pans under the brandname Tefal. In the United States, Marion A. Trozzolo, who had been using the substance on scientific utensils, marketed the first US-made Teflon-coated pan, The Happy Pan, however, Tefal was not the only company to utilize PTFE in nonstick cookware coatings. Other cookware companies, such as Meyer Corporations Anolon, use Teflon nonstick coatings purchased from DuPont, in the 1990s, it was found that PTFE could be radiation cross-linked above its melting point in an oxygen-free environment. Electron beam processing is one example of radiation processing, cross-linked PTFE has improved high-temperature mechanical properties and radiation stability. This was significant because, for years, irradiation at ambient conditions has been used to break down PTFE for recycling. This radiation-induced chain scission allows it to be more easily reground, PTFE is produced by free-radical polymerization of tetrafluoroethylene
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Chlorate
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The chlorate anion has the formula ClO−3. In this case, the atom is in the +5 oxidation state. Chlorate can also refer to compounds containing this anion, chlorates are the salts of chloric acid. Chlorate, when followed by a Roman numeral in parentheses, e. g. chlorate, as predicted by VSEPR, chlorate anions have trigonal pyramidal structures. Chlorates are powerful oxidizers and should be away from organics or easily oxidized materials. Mixtures of chlorate salts with virtually any material will readily deflagrate. Chlorates were once used in pyrotechnics for this reason, though their use has fallen due to their instability. Most pyrotechnic applications that formerly used chlorates now use the more stable perchlorates instead, the chlorate ion cannot be satisfactorily represented by just one Lewis structure, since all the Cl–O bonds are the same length, and the chlorine atom is hypervalent. Chlorine, oxidation number 0, forms chloride Cl− and chlorate ClO−3, the reaction of cold aqueous metal hydroxides with chlorine produces the chloride and hypochlorite instead. The industrial scale synthesis for sodium chlorate starts from aqueous chloride solution rather than chlorine gas. If the equipment for electrolysis allows for the mixing of the chlorine, the heating of the reactants to 50–70 °C is performed by the electrical power used for electrolysis. A recent study has discovered the presence of natural chlorate deposits around the world, the chlorate was also measured in rainfall samples with the amount of chlorate similar to perchlorate. It is suspected that chlorate and perchlorate may share a natural formation mechanism. From a microbial standpoint, the presence of natural chlorate could also explain why there is a variety of microorganisms capable of reducing chlorate to chloride. Further, the evolution of chlorate reduction may be an ancient phenomenon as all perchlorate reducing bacteria described to also utilize chlorate as a terminal electron acceptor. Commonly, chlorate refers only to chlorine in the +5 oxidation state, chlorates are relatively toxic, though they form generally harmless chlorides on reduction
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Static electricity
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Static electricity is an imbalance of electric charges within or on the surface of a material. The charge remains until it is able to move away by means of a current or electrical discharge. Static electricity is named in contrast with current electricity, which flows through wires or other conductors, a static electric charge can be created whenever two surfaces contact and separate, and at least one of the surfaces has a high resistance to electric current. The familiar phenomenon of a static shock–more specifically, an electrostatic discharge–is caused by the neutralization of charge, materials are made of atoms that are normally electrically neutral because they contain equal numbers of positive charges and negative charges. The phenomenon of static electricity requires a separation of positive and negative charges, when two materials are in contact, electrons may move from one material to the other, which leaves an excess of positive charge on one material, and an equal negative charge on the other. When the materials are separated they retain this charge imbalance and this is known as the triboelectric effect and results in one material becoming positively charged and the other negatively charged. The polarity and strength of the charge on a material once they are separated depends on their positions in the triboelectric series. The triboelectric effect is the cause of static electricity as observed in everyday life. Contact-induced charge separation causes your hair to stand up and causes static cling, pressure-induced charge separation Applied mechanical stress generates a separation of charge in certain types of crystals and ceramics molecules. Heat-induced charge separation Heating generates a separation of charge in the atoms or molecules of certain materials, all pyroelectric materials are also piezoelectric. The atomic or molecular properties of heat and pressure response are closely related, charge-induced charge separation A charged object brought close to an electrically neutral object causes a separation of charge within the neutral object. Charges of the same polarity are repelled and charges of the opposite polarity are attracted, as the force due to the interaction of electric charges falls off rapidly with increasing distance, the effect of the closer charges is greater and the two objects feel a force of attraction. The effect is most pronounced when the object is an electrical conductor as the charges are more free to move around. Careful grounding of part of an object with a charge separation can permanently add or remove electrons, leaving the object with a global. This process is integral to the workings of the Van de Graaff generator, removing or preventing a buildup of static charge can be as simple as opening a window or using a humidifier to increase the moisture content of the air, making the atmosphere more conductive. Air ionizers can perform the same task, fabric softeners and dryer sheets used in washing machines and clothes dryers are an example of an antistatic agent used to prevent and remove static cling. Many semiconductor devices used in electronics are particularly sensitive to static discharge, conductive antistatic bags are commonly used to protect such components. People who work on circuits that contain these devices often ground themselves with an antistatic strap
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Underground press
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The terms underground press or clandestine press refer to periodicals and publications that are produced without official approval, illegally or against the wishes of a dominant group. It can also refer to the newspapers produced independently in repressive regimes, in German occupied Europe, for example, a thriving underground press operated, usually in association with the Resistance. Other notable examples include the samizdat and bibuła, which operated in the Soviet Union and Poland respectively, each paper was the organ of a separate resistance network, and funds were provided from Allied headquarters in London and distributed to the different papers by resistance leader Jean Moulin. Allied prisoners of war published a newspaper called Pow wow. In Eastern Europe, also approximately the 1940, underground publications were known by the name samizdat. The countercultural underground press movement of the 1960s borrowed the name from previous underground presses such as the Dutch underground press during the Nazi occupations of the 1940s and those predecessors were truly underground, meaning they were illegal, thus published and distributed covertly. Published as weeklies, monthlies, or occasionals, and usually associated with left-wing politics, they evolved on the one hand into todays alternative weeklies and on the other into zines. The most prominent underground publication in Australia was a magazine called Oz. The original Australian edition appeared in 1963 and it continued sporadically until 1969, richard Neville arrived in London from Australia where he had edited Oz. He launched a British version, which was A4, very quickly, the relaunched Oz shed its more austere satire magazine image and became a mouthpiece of the Underground. It was the most colourful and visually adventurous of the alternative press, Other publications followed, such as Friends, based in the Ladbroke Grove area of London, Ink, which was more overtly political, and Gandalfs Garden which espoused the mystic path. Neville published an account of the counterculture called Playpower, in which he described most of the underground publications. The underground press offered a platform to the socially impotent and mirrored the changing way of life in the UK underground, the police campaign may have had an effect contrary to that which was presumably intended. If anything, according to one or two who were there at the time, it made the underground press stronger. It focused attention, stiffened resolve, and tended to confirm that what we were doing was considered dangerous to the establishment, remembered Mick Farren. From April 1967, and for some later, the police raided the offices of International Times to try, it was alleged. In order to raise money for IT a benefit event was put together, on one occasion - in the wake of yet another raid on IT - Londons alternative press succeeded in pulling off what was billed as a reprisal attack on the police. The paper Black Dwarf published a detailed floor-by-floor Guide to Scotland Yard, complete with diagrams, descriptions of locks on particular doors, and snippets of overheard conversation
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Thermite
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Thermite is a pyrotechnic composition of metal powder, fuel and metal oxide. When ignited by heat, thermite undergoes an exothermic reduction-oxidation reaction, most varieties are not explosive but can create brief bursts of high temperature in a small area. Its form of action is similar to that of other fuel-oxidizer mixtures, fuels include aluminium, magnesium, titanium, zinc, silicon, and boron. Aluminium is common because of its boiling point and low cost. Oxidizers include bismuth oxide, boron oxide, silicon oxide, chromium oxide, manganese oxide, iron oxide, iron oxide, copper oxide, the reaction, also called the Goldschmidt process, is used for thermite welding, often used to join rail tracks. Thermites have also used in metal refining, demolition of munitions. Some thermite-like mixtures are used as pyrotechnic initiators in fireworks, the reactants are commonly powdered and mixed with a binder to keep the material solid and prevent separation. Other metal oxides can be used, such as chromium oxide, the thermite reaction was discovered in 1893 and patented in 1895 by German chemist Hans Goldschmidt. Consequently, the reaction is called the Goldschmidt reaction or Goldschmidt process. Goldschmidt was originally interested in producing very pure metals by avoiding the use of carbon in smelting, the first commercial application of thermite was the welding of tram tracks in Essen in 1899. Red iron oxide is the most common iron oxide used in thermite, other oxides are occasionally used, such as MnO2 in manganese thermite, Cr2O3 in chromium thermite, quartz in silicon thermite, or copper oxide in copper thermite, but only for specialized purposes. All of these examples use aluminium as the reactive metal, fluoropolymers can be used in special formulations, Teflon with magnesium or aluminium being a relatively common example. Magnesium/teflon/viton is another pyrolant of this type, combinations of dry ice and reducing agents such as magnesium, aluminum and boron follow the same chemical reaction as with traditional thermite mixtures, producing metal oxides and carbon. Despite the very cold temperature of a dry ice thermite mixture, in principle, any reactive metal could be used instead of aluminium. This is rarely done, because the properties of aluminium are nearly ideal for this reaction, It is by far the cheapest of the highly reactive metals. For example, in Dec 2014, tin was 19,830 USD/Metric Ton, zinc was 2,180 USD/MT and aluminium was 1,910 USD/MT It forms a passivation layer making it safer to handle than many other reactive metals. Its relatively low melting point means that it is easy to melt the metal, so that the reaction can occur mainly in the liquid phase and thus proceeds fairly quickly. Its high boiling point enables the reaction to reach high temperatures
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Gunpowder
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Gunpowder, also known as black powder, is the earliest known chemical explosive. It is a mixture of sulfur, charcoal, and potassium nitrate, the sulfur and charcoal act as fuels, and the saltpeter is an oxidizer. Black powder firearms are in limited use today in hunting, shooting, Black powder has been replaced for most industrial uses by high explosives such as dynamite. Black powder is assigned the UN number UN0027 and has a class of 1. 1D. It has a point of approximately 427–464 °C. The specific flash point may vary based on the composition of the gunpowder. Gunpowders specific gravity is 1. 70–1.82 or 1. 92–2.08, Gunpowder is classified as a low explosive because of its relatively slow decomposition rate and consequently low brisance. Low explosives deflagrate at subsonic speeds, whereas high explosives detonate, ignition of the powder packed behind a bullet must generate enough pressure to force it from the muzzle at high speed, but not enough to rupture the gun barrel. Gunpowder thus makes a good propellant, but is suitable for shattering rock or fortifications. Gunpowder was widely used to fill artillery shells and in mining and civil engineering to blast rock until the half of the 19th century. Black powder is used as a delay element in various munitions where its slow-burning properties are valuable. The spread of gunpowder across Asia from China is widely attributed to the Mongols, the earliest record of a written formula for gunpowder appears in the 11th century Song dynasty text, Wujing Zongyao. This discovery led to the invention of fireworks and the earliest gunpowder weapons in China, in the centuries following the Chinese discovery, gunpowder weapons began appearing in the Muslim world and Europe. The technology spread from China through the Middle East or Central Asia, the earliest Western accounts of gunpowder appear in texts written by English philosopher Roger Bacon in the 13th century. The most ardent protagonists were Nathaniel Halhad, Johann Backmann, Quintin Craufurd, however, due to lack of sufficient proof, these theories have not been widely accepted. A major problem confronting the study of the history of gunpowder is ready access to sources close to the events described. The translation difficulty has led to errors or loose interpretations bordering on artistic licence, early writings potentially mentioning gunpowder are sometimes marked by a linguistic process where old words acquired new meanings. For instance, the Arabic word naft transitioned from denoting naphtha to denoting gunpowder, saltpeter was known to the Chinese by the mid-1st century AD and there is strong evidence of the use of saltpeter and sulfur in various largely medicinal combinations
