Nitrogen gas, floating in the air, has long been considered a lazy substance. It seems to be uninterested in everything, neither aiding combustion nor sustaining life. Writing nitrogen as "diluent" means: "It dilutes the oxygen in the air."

People harness the solitary nature of nitrogen to serve humanity. Many light bulbs are filled with nitrogen to slow down the evaporation of the tungsten filament. In thermometers measuring temperatures from 300 to 500 degrees Celsius, nitrogen is often filled above the mercury column to prevent boiling and oxidation under high heat. Some museums store valuable and rare manuscripts in cylinders filled with nitrogen, as pests cannot survive in it and thus cannot cause damage. In recent years, our country has also covered grain with massive plastic tents, removing the air inside and replacing it with nitrogen. This prevents the growth of mold and pests, inhibits the respiration of the grain, and allows for long-term safe storage. This new method of grain preservation is called "vacuum nitrogen preservation." Nitrogen is generally unassuming and doesn't meddle in others' affairs, but under high temperatures, it becomes like an enthusiastic young person. This has caused quite a bit of trouble for steel mills, as during the steelmaking process, the steel turns into molten red steel, and nitrogen easily dissolves into the molten steel. However, when the steel ingot cools, the nitrogen escapes, forming bubbles within the ingot. Such honeycomb steel cannot be used to manufacture machines. Now, steelworkers add metallic titanium to the molten steel, which reacts with nitrogen to form slag, with titanium nitride floating on the surface. Many nitrogen compounds are very hard, like the compound of nitrogen and silicon, which can be used for metal cutting. In the chemical industry, nitrogen compounds are crucial, playing a leading role in explosives, nitrogen fertilizers, dyes, and nitric acid production. For example, nitrogen compounds form ammonia. When combined with other chemical raw materials, ammonia can be used to produce various nitrogen fertilizers, such as ammonium nitrate, ammonium bicarbonate, and urea. Urea is also an important chemical raw material for manufacturing plastics and synthetic fibers. In nature, a rainstorm often accompanied by lightning produces a spark that can extend for tens of kilometers. During this time, much nitrogen burns in the presence of oxygen, and the resulting nitrogen dioxide dissolves in raindrops, forming nitric acid, which falls to the soil and becomes a precious source of nitrogen fertilizer.