Man's physical universe



ammonium phosphate, or some other salt which partially fireproofs

them so that the wood ceases to glow as soon as the flame is extinquished.

Modern "strike anywhere" matches are tipped with a mixture of

phosphorus sulfide, P4S3, and some oxidizing material such as potassium

chlorate, KCIO3, powdered glass or some other material to increase

the friction, and glue to bind the ingredients to the match. The wood

The Principle of the Match Is Employed in Fireworks.

The essential principle employed in the manufacture of matches and

fireworks is to use a mixture of a readily oxidizable material and a

powerful oxidizing agent, the components of which will react with

each other as soon as the kindling temperature is reached. The reaction

is usually a specialized kind of combustion in which the oxygen is


by a compound which readily gives it up on heating. The old

black gunpowder was a mixture of powdered charcoal (14 per cent),

sulfur (11 per cent), and potassium nitrate (75 per cent).

is usually impregnated with paraffin to render it more readily inflammable.

In this case

potassium nitrate, KNO3, furnishes the oxygen for the combustion of

the carbon and sulfur to form a mixture of gases. Gunpowder is still

used for mining operations and in pyrotechnic displays, but it has been

replaced for use in guns by more powerful smokeless powders.

Firecrackers are made by wrapping gunpowder in paper. Flash

crackers use a mixture of magnesium and some oxidizing agent such

as potassium chlorate instead of gunpowder. Colored lights are produced

by mixing various substances such as strontium chlorate with

mixtures similar to gunpowder. Strontium salts produce red fire;

barium, green; sodium, yellow; magnesium and aluminum, white; and

Paris green blue.

Magnesium is used in warfare for incendiaries and flares because, as

it burns, its temperature is raised to the boiling-point, producing

magnesium vapor which burns in air with a very hot flame of great

brilliance. Magnesium is used in incendiary bombs partly because of

its low density. It is ignited with thermite. Once ignited, burning

magnesium, instead of being extinguished by water, reacts with water

to produce hydrogen which burns with even greater intensity than the

magnesium itself. Magnesium bombs are extinguished by covering

them with sand or asbestos blankets to shut off the oxygen supply.

Thermite is a mixture of iron oxide and aluminum, which, when

ignited by a primer of aluminum or magnesium powder mixed with

some oxidizing agent such as barium peroxide, Ba02, burns furiously.

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