Kyle Spriggs, age 16, of Asbury Park, N.J., for his question:
JUST WHAT IS NITROGEN?
Nitrogen is a gaseous element. Nitrogen makes up as important pact of the bodies of humans, animals and plants. It is a necessary part of the protein substance that is man's body building material.
Seventy eight percent of the air people breathe is mace up of nitrogen, while only 21 percent is oxygen. There are about 20 million tons of nitrogen above every square mile of the earth's surface.
Without nitrogen, no one could grow or repair damageo or worn out tissues.
Nitrogen also has many important commercial uses. Fertilizers and explosives are just two of the leading nitrogen products.
Human bodies can't use pure nitrogen. When breathes in, it acts only to dilute the oxygen. Nitrogen is useful only when combined with other chemicals to form compounds. It is chemically inactive and does not combine easily with other elements.
In nature, only a few plants, known as legumes, are able to use pure nitrogen from the air. Legumes include beans, peas, clover and alfalfa. Certain bacteria that live in their roots take the atmospheric nitrogen and change it into a suitable form.
All plants can use the simple nitrogen compounds of the soil to make proteins they need in order to grow. Animals can't make proteins from simple compounds. They must eat plants or each other to get proteins.
When plants oz animals decay, their nitrogen is returned to the soil. A certain amount is also added from the nitrogen compounds formed by lightning in air and washed down by rain.
Crops will not grow well if the soil is low in nitrogen. A farmer may solve the problem by growing alfalfa or clover in the field for a season o= two to enrich the soil, or he may insteaa add manure or artificial nitrogen fertilizer to the soil.
A scientific problem was how to take nitrogen out of the air and coax it into combination with other elements. The first to be even partly successful was an American chemist, Charles Bradley. In 1902 he forced air through the intense heat of an electric arc, thus making the nitrogen and oxygen join to form cxides of nitrogen, which he absorbed in water to form a dilute solution of nitric acid. The development of this discovery passed to Norway, where lots of cheap electric power from water was available.
Just before world war I, German chemists perfected another process that easily extracted nitrogen from the air and made it into compounds.
The German process was developed by a man named Fritz Haber. Nitrogen from liquid air is mixed with hydrogen and, under a pressure of 3,000 pounds to the square inch, is passed over a catalyst at 500 degrees Centigrade.
The catalyst iron, together with aluminum and potassium oxides, helps the nitrogen and hydrogen combine to form ammonia. Then it is combined with oxygen to form nitric acid.