Susan Modjeska, Age 11, Of Peoria, I11., for her question:
What is the substance known as ozone?
We know of 103 chemical elements, and their 103 different atoms are charted on the periodic table. The substance known as ozone is rated as an element, but it does not rate a slot of its own on this orderly chart. And it has more contrary puzzles for us to ponder.
An extra smidgen of ozone adds a peppy note to the air, but in pure form it can ruin the lungs. It has a strong pungent odor, yet it can deodorize the strong pungent sme11s of a meat market. It is rated as a poison and also as a purifier of food and water. Add to these contradictions the fact that it is an element not named on the periodic table of elements, and ozone appears to be a substance with a split personality.
The atom from which ozone is made, however, is described on the periodic tab1e in the slot marked 0 for oxygen. It is an allotrope of oxygen, and allotropes are different forms of the same element or compound. The atoms of ozone and oxygen are identical. Oxygen is very active, always eager to combine and form molecules with other elements.
Oxygen atoms in the air tend to unite in pairs and form oxygen molecules. Sometimes a third oxygen atom is added and the twins become triplets. Ozone is a triplet m01ecule made from three oxygen atoms. It is a blue gas, somewhat denser and a great deal more actiye than oxygen. A lot of energy is 1bsed t0 conyert oxygen to ozone, and the triplet molecules soon break apart again into twins and single atoms.
The searing energy of lightning creates ozone in the air, and we often get a breath of its bracing odor after a storm. The sun's ultraviolet rays also create ozone in the air, and man made ozone is created with the energy from powerful electrical discharges. When the triplet molecules of ozone break apart, the energy used to create them is released.
Ozone spends its energy by reacting with various chemicals around it. It attacks dirt and kills germs, it steals colors and meaty odors. In industry ozone is used to cure wood, to cleanse and bleach textiles, oils, waxes and varnishes. As an antiseptic it is the mortal enemy of microbes. Though ozone itself is a poison it may be used to purify food and water, for, when its busy germ killing work is done, its triplet molecules have become harmless oxygen.
There is enough ozone in the atmosphere to spread a layer three feet deep upon the surface of the globe. This seems a large amount, especially when we remember that pure ozone is a poison. Actually, its triple molecules are spread very sparsely through our vast ocean of air. Ozone accounts for only one part in about 450,000 parts of ordinary air, and even the extra whiffs created by thunderstorms are no threat to us.