Phenomenon of magnesium bar burning in air

Magnesium bars burn in the air: giving off dazzling light and a lot of heat, producing white smoke and a kind of white material.

Brief introduction of magnesium belt:

Generally speaking, it refers to metallic magnesium prepared into strips, with the chemical symbol of Mg, which is a silvery white solid with metallic luster. The magnesium content in magnesium strips is generally above 99.96%, which is insoluble in water, but can react with hot water. Melting point is 648℃, boiling point 1 107℃, combustible, and ignition point is 480 ~ 5 10℃.

Use:

1. Don't touch the magnesium belt with your hands during the experiment (there is high temperature);

2. When igniting, clamp the magnesium belt with crucible tongs (iron tongs), and the burning magnesium belt emits a lot of light and heat. (Note: Don't look at the light for too long, because the magnesium belt is very bright when burning, which may have some influence on the eyes);

3. It turns into pure white powder like lime after burning. After combustion, the product (namely magnesium oxide) can be observed on the asbestos net. Don't put it directly on the table to avoid polluting the desktop. If a pale yellow solid is generated, it is magnesium nitride.

Application of magnesium tape in photography history;

Photographers should prepare a certain amount of flash powder in advance before taking pictures, and then manually light it while pressing the shutter in loud noise, flash and white smoke. Magnesium powder powder is not safe, so there are not a few photographers who were injured by explosion when mixed with powder. Photographers with curly hair and black smoke have become a common ridicule theme in comics.

But thanks to the strong light of magnesium powder, objects in the dark can also be imaged on the negative, and the faster shutter speed makes the instantaneous motion freeze on the film, which greatly expands the application field of photography.

With the development of electric power, emerging energy technologies have brought some changes to photographers who play with fire. The heat generated by the current passing through the fuse is used to ignite magnesium powder. This new product is called flash, which is the origin of the word "flash" today.

Photographers no longer have to worry about being caught by the fire. More importantly, they can realize the synchronization of flashing and shooting through electronic circuits, which greatly expands the application range of flash.