Traditional Culture Encyclopedia - Photography and portraiture - Application of magnesium strip combustion
Application of magnesium strip combustion
The application of burning magnesium strips is as follows:
Magnesium strips generally refer to metal magnesium prepared in a strip shape. The chemical symbol is Mg and its appearance is a silver-white solid with metallic luster. The magnesium content in the magnesium ribbon is generally above 99.96%. It is insoluble in water, but can react with hot water. The melting point is 648°C, the boiling point is 1107°C, and it can burn. The ignition temperature is 480~510°C.
Do not touch the magnesium ribbon with your hands during the experiment (there is high temperature); when igniting, use crucible tongs (iron tongs) to clamp the magnesium ribbon. The burning magnesium ribbon emits a lot of light and releases a lot of heat. (Note: Do not look at the light for too long, because the magnesium ribbon burns very brightly, which may have a certain impact on the eyes);
After burning, it turns into a pure white powder similar to lime. Just put the substance (i.e. magnesium oxide) on the asbestos net and observe it. (Do not place it directly on the table to avoid contaminating the table.) If a light yellow solid is produced, it is magnesium nitride.
The magnesium bar and oxygen react 2Mg+O2→2MgO (reaction conditions: ignition or slow oxidation) the magnesium bar and oxygen generate magnesium oxide. The magnesium bar reacts with carbon dioxide 2Mg+CO2→C+2MgO (reaction conditions: ignition). The magnesium bar reacts with carbon dioxide to produce magnesium oxide and carbon elements.
The combustion of magnesium strips consumes oxygen and nitrogen, but it can also burn in carbon dioxide and is one of the few metals that can burn in carbon dioxide. The reaction between magnesium strip and dilute hydrochloric acid Mg+2HCl→MgCl2+H2↑
This is a violent chemical reaction of magnesium strip in hydrochloric acid, which will generate a large amount of heat and is an exothermic chemical change. Use test tube clamps to hold test tubes to avoid burns.
Anode applications are used in high resistivity environments, protection of pipelines in casings, temporary cathodic protection of pipelines, protection of storage tanks and pipe networks, grounding grids to prevent strong electrical interference, etc.
The application of magnesium tape in the history of photography. Photographers must pre-prepare a certain amount of flash gunpowder before taking pictures, and then manually ignite it while taking pictures while pressing the button amidst loud noises, flashes and white smoke. shutter.
Magnesium powder gunpowder is not very safe, so many photographers have been injured by the explosion when mixing gunpowder. Photographers who were accidentally affected by gunpowder while taking pictures, with curly beards and hair, and black smoke have also become Common ridicule themes in comics.
But thanks to the strong light of magnesium powder, objects in the dark can also be imaged on the film. The faster shutter speed allows the instantaneous dynamics to be solidified on the film. The application field of photography has been Greatly expanded.
With the development of electricity, emerging energy technologies have brought some changes to photographers who play with gunpowder. The heat generated by the current passing through the fuse was used to ignite the magnesium powder gunpowder. This new product was called a Flash-lamp, which is the origin of today's flash lamp.
Photographers no longer have to worry about being caught in the fire. More importantly, they can synchronize flash and shooting through electronic circuits, which greatly expands the scope of flash use.
The king of spotlights in the photography world ended in the 1960s. The xenon flash tube invented by Harold Edgerton of MIT in 1927 was miniaturized and introduced to the market. It was immediately known as the electronic flash tube. The flash bulbs that have to be replaced every time they are used cannot be compared with the electronic flashes that can be used multiple times as long as there is a power source in terms of cost and convenience.
The real spotlight That’s when I quit mainstream photography. Today's smart electronic flashes have become an indispensable part of the camera system, and their functions are far better than their ancestors.
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