Science in the Service of Man

There is no doubt that modern science contributes an ample share to making life easier. Very many indeed are the inventions and scientific discoveries that find practical applications in our daily lives. Add to this that these applications have entered into the very core of our lives, to the point where they are no longer luxuries but have become necessities demanded by the pattern on which we live. Electricity and its applications — radio, telephone, and telegraph — have all become an inseparable part of our civilization. Yet many of us enjoy these inventions and discoveries and use them daily without ever having acquainted themselves with the theoretical scientific principles that made the existence of these practical applications possible. In my view, the person who knows how the electric lamp gives light, for example, enjoys it the more and trusts it the more; for the more a man satisfies his scientific curiosity, the better he understands the scientific side of modern civilization, and the more he appreciates the services that science renders toward increasing man's prosperity.

In this article I shall try to set forth for the honored readers some of the fundamental principles on which electricity rests, because electricity constitutes the greatest motive power in the modern world, and because acquaintance with its principles opens the way to understanding many of its practical applications. But we must first cast a glance at the structure of matter before beginning our inquiry into electricity.

What is matter composed of?

We know that matter is made up of molecules, and these in turn are made up of atoms. Molecules and atoms differ as matter differs: the molecules of water, for example, are composed of the two elements oxygen and hydrogen, while the molecules of petroleum are composed of the two elements carbon and hydrogen. Yet however much the molecules or atoms of matter may differ, they all resemble one another in their construction; for all atoms, whatever their kind, their source, and the matter to which they belong, are built up of similar electrical units. Just as a man can build several houses of different appearance and shape from a single kind of stone, so nature builds the different elements from these similar electrical units. And just as the difference between the houses referred to is a difference in the arrangement of the stones, according to the architectural form to be brought out — not a difference in the unit of building, which is the stone — so the difference between the elements iron and copper, for example, is a difference in the arrangement of these electrical units, an arrangement that gives iron properties and characteristics distinguishing it from the properties and characteristics of copper.

The arrangement of the electrical units in the atom:

These electrical units, then, are the foundation on which matter is built. They are either negative, and are called electrons, or positive, and are called protons. These units are exceedingly small in size; no microscope can show them to us. A single gram of matter contains millions of millions of these infinitesimally minute electrical units. And though they cannot be seen, modern science possesses various means of proving conclusively that they exist. The protons, or positive units, are larger in size and heavier than the electrons, or negative units: the weight of a single proton equals the weight of 1,845 electrons. And this great difference in weight results from the electrons being more active and more mobile than the protons.

These electrical units, the electrons and protons, join together in building the atoms of matter. The atom, then, is nothing but an organized group of these negative and positive units, which are always present in equal quantities; the number of electrons neither exceeds the number of protons nor falls short of it. The atom consists of a nucleus containing all the protons together with some of the electrons, gathered into a dense, compact mass around which the remaining electrons revolve. We may liken the nucleus to the sun, with the electrons revolving around it as the planets revolve around the sun. Whenever the number of these units differs, the kind of element, or of the matter to which they belong, differs. The oxygen atom, for example, contains sixteen electrons and sixteen protons, while the iron atom is composed of fifty-six electrons and fifty-six protons; the gold atom of one hundred and ninety-seven electrons and as many protons; and the radium atom of two hundred and twenty-six electrons and as many protons. The difference, then, is at bottom a difference of number. Everything we call "matter" is composed of these minute electrical units: stone, iron, paper, plant, animal, and man — each of them is matter, or rather materials, built at bottom of electrons and protons.

Now that we have gained this acquaintance with the structure of matter, we can inquire into electricity.

We said above that the electrons are lighter in motion and more active than the protons. But these electrons move in order within the solar system of the atom: they revolve and revolve, forever and always. If, however, we can isolate these electrons and make them all travel in a defined direction, the result is what we call the electric current. Electricity, then, is nothing but streams of these electrons as they pass from one place to another.

And just as ease of travel depends to a great extent on the roughness or the goodness of the road, so the ease with which the throngs of electrons pass through a given body depends to a great extent on the capacity of that body to facilitate the passage of these throngs. Copper wires, for example, allow them to pass with great ease, and for that reason they are much used in carrying electric power from one place to another; while air allows the electrons to pass only with great difficulty, and under the influence of an electric force greater than the force these electrons need in order to travel through the copper wire. This difference in the ease with which electricity travels through different bodies, and the light and heat generated as a result of it, is one of the theoretical foundations on which electric lighting rests.

The electric lamp, or "bulb," is composed of a fine wire, usually made of a metal called tungsten. This wire is fixed inside a glass tube of spherical shape, as we all know, and is connected at its end with the source of the electric current outside. The lamp must be tightly sealed and emptied of air, because air contains the element oxygen, which reacts with the tungsten metal and renders it unfit for lighting for any length of time. The air is replaced by a gas called argon, an inactive gas which does not combine with the tungsten but helps to preserve it longer than if the lamp were emptied of all gas; for in that case — the case of absolute vacuum — the tungsten evaporates quickly, and the wire becomes incapable of long service. The presence of argon gas, then, is of double benefit: it reduces the amount of the tungsten's evaporation, and it does not react with it as does the oxygen present in the air.

As for the reason tungsten metal was chosen, it is that it melts only under the influence of a very high temperature — 3,370 degrees centigrade.

Let us now try to picture how electricity runs through the lamp. We said that the electric current is a great multitude of electrons traveling in one direction. When the electric current reaches one of the two ends of the metal wire in the lamp, these electrons try to travel inside it so as to pass out at the other end; and in their attempt to travel through this wire they meet with some difficulty. But they are compelled to travel, because they are all pushed by the electric force drawn from the town's electricity stations. Thus the difficulty of the electrons' passage through the metal wire generates friction between them and the atoms of tungsten. This friction causes the temperature of the wire to rise, just as one of us feels heat in his palms if he rubs one against the other. The greater the friction between the electrons and the tungsten atoms, the higher the temperature of the metal wire rises, until, when this heat reaches a certain degree, the wire begins to glow. Heat and light are in truth two different expressions of a single principle: any body that sends out a ray, or light, is a body whose heat has reached the degree of incandescence. A piece of cold iron gives no light at all; but if the blacksmith's fire is turned upon it, we see it glow red and send out a shining ray.

Hence, if the tungsten metal, in the state in which it exists inside the lamp, allowed the electrons to pass with great ease, no friction would occur and no light would be generated. And since it is a metal that melts only under very high heat, the heat produced by the friction referred to does not affect this wire as it would affect a wire that melts under low heat.

This has been a very summary inquiry into the theoretical side of electricity and into one practical application of it. My great hope is that this brief exposition may serve as an incentive to the honored readers to try to widen their knowledge of this important subject. For science is a sea of vast horizons: the deeper a man plunges into it, the greater grows his passion for it and his attachment to it.

If this article has been able to spur some readers to widen their knowledge, it will have achieved the essential purpose for which it was written.